1

1 The diagram shows a section through the heart of a mammal

B

AC

(a) Name the parts labelled A B and C

A

B

C (3)

(b) Each time the heart beats the atria contract first and then the ventricles contract Explain how this sequence of events is coordinated

(4)

(Total 7 marks)

2

2 Coronary heart disease (CHD) is a major cause of death in developed countries and accounts for over 160 000 deaths each year in the United Kingdom One of the main causes of CHD is atherosclerosis a condition in which lipids and connective tissue build up on the inside wall of blood vessels

(a) State two consequences of atherosclerosis which may lead to the development of CHD in an individual

1

2

(2)

(b) The table shows deaths from coronary heart disease as a percentage of all deaths in the United Kingdom in 1983

Percentage of all deaths

Age years Males Females

0ndash14 4 3

15ndash24 7 10

25ndash34 15 14

35ndash44 37 18

45ndash54 53 26

55ndash64 53 37

65ndash74 53 50

75 and over 51 56

(i) Which two risk factors associated with the development of CHD are indicated in the table

(1)

3

(ii) With reference to the data in the table compare the percentage of deaths from CHD in males and females

(3)

(Total 6 marks)

3 The diagram below shows cross-sections of three different types of blood vessel A B and C

A B C

5 mm 5 mm 0005 mm

(a) Name the blood vessels A and B

A

B (1)

4

(b) State two ways in which blood vessel C is adapted to enable the formation of tissue fluid

1

2

(2)

(c) Give one function of tissue fluid

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(d) When tissue fluid is not efficiently reabsorbed it collects in tissues causing swelling (oedema) Suggest one factor that could cause oedema

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 5 marks)

4 The graph below shows changes in the blood pressure in the aorta and the left ventricle during two complete cardiac cycles

20

15

10

5

00 02 04 06 08 10 12 14 16 18

Time s

Pressure kPa Aortic pressure

Leftventricularpressure

(a) On the graph draw an arrow to show when the left atrioventricular (mitral) valve closes (1)

5

(b) Use the information in the graph to calculate the heart rate Show your working

Answer (2)

(c) During the cardiac cycle the pressure in the left ventricle falls to a much lower level than in the aorta Suggest an explanation for this difference

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(d) During the cardiac cycle the pressure in the right ventricle rises to a maximum of about 33 kPa Suggest reasons for the difference between this pressure and the maximum pressure in the left ventricle

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(Total 9 marks)

5 Explain what is meant by each of the following terms

6

(a) The cardiac cycle

(3)

(b) Coronary circulation

(3)

(Total 6 marks)

7

6 The diagram below shows an outline of the double circulation in a mammal

(a) Name the chambers of the heart labelled A and B

A

B (2)

(b) Name the organ in which the capillaries labelled C would be found

(1)

8

(c) The heart maintains a high pressure of oxygenated blood in the arteries to the body Explain how a double circulation is important in bringing this about

(3)

(d) The photomicrograph below shows a transverse section through blood vessels

(i) Give the names of the two types of blood vessel D and E

D

E (1)

9

(ii) Describe one characteristic feature that you used to identify D

(1)

(Total 8 marks)

7 The following information is taken from a web site promoting a margarine

Cholesterol in the body comes from two sources A small amount is eaten in certain foods but most is actually produced by our liver and we need some in our bodies to stay healthy The liver produces cholesterol when saturated fats are eaten Todayrsquos diet contains a lot of saturated fat and therefore the liver produces more cholesterol than the body actually requires To complicate matters there are two types of cholesterol ndash HDL (good) and LDL (bad) cholesterol

Our healthier margarine is a low fat spread enriched with plant sterols Plant sterols have been clinically proven to lower cholesterol levels by reducing the cholesterol being absorbed from the gut This helps to maintain a healthy heart

Independent clinical trials prove that moving to a diet that includes 20ndash25 g of healthier margarine per day gives average LDL cholesterol reductions of 10ndash15 There is no effect on HDL cholesterol If you eat less than this amount you will still see a reduction although it will not be as high as it could be Eating more will not give a significantly greater cholesterol lowering effect

(a) Give one way in which cholesterol in our bodies ensures that we lsquostay healthyrsquo

(1)

10

(b) Explain how high levels of LDL can affect the risk of heart disease

(4)

(c) Use information from the passage to suggest

(i) one way other than eating margarine in which blood cholesterol levels could be reduced by a change of diet

(1)

(ii) a reason why eating more than 20ndash25 g of healthier margarine a day lsquowill not give a significantly greater cholesterol lowering effectrsquo

(2)

(Total 8 marks)

11

8 (a) The table below refers to structural features of two types of blood vessels If the feature is correct place a tick ( ) in the appropriate box and if the feature is incorrect place a cross ( ) in the appropriate box

Blood vessel Structural feature

Valves present Wall has pores Wall a single layer of cells

Capillary

Vein (3)

(b) The wall of the aorta a major artery has many elastic fibres in it Suggest a reason for the presence of these fibres

(1)

(Total 4 marks)

9 (a) Describe three structural differences between arteries and veins

Arteries Veins

1

2

3

(3)

12

(b) Suggest why arteries are more likely than veins to develop atherosclerosis

(1)

(c) The diagram below shows how tissue fluid is formed from blood plasma

Describe and explain how fluid is forced out of the capillaries to form tissue fluid at the arterial end of the capillary

(2)

(d) (i) Give one reason why fluid might accumulate within the tissues and cause swelling

(1)

13

(ii) Name this type of swelling in the tissues

(1)

(Total 8 marks)

10 The composition of our diet may be associated with the development of disease in a number of our body organs Explain how diet may be associated with the development of the following diseases

Coronary heart disease (CHD)

(Total 3 marks)

11 The diagrams below show a pig (a mammal) and a flatworm (a small pond animal)

times005 times5

14

(a) Explain why a pig has a heart and circulatory system whereas a flatworm does not

(2)

(b) The diagram below shows a cross-section of a mammalian heart The positions of the valves are shown by the four circles

(i) On the diagram indicate whether each valve is open or closed during ventricular systole (contraction of the ventricles) by writing lsquoopenrsquo or lsquoclosedrsquo on the lines provided Do not draw the valves

(2)

(ii) Indicate the position of the sino-atrial node (pacemaker) by drawing a cross on the diagram

(1)

(iii) State the role of the sino-atrial node

(1)

15

(c) Suggest two advantages of the coronary artery branching directly off the aorta

1

2

(2)

(Total 8 marks)

12 (a) The diagram below summarises some of the steps involved in blood clotting Complete the diagram by writing in the missing words in the boxes

Thrombin

Fibrin

Thromboplastin released by damaged cells and

(3)

(b) Describe the possible effects of a blood clot forming in a coronary artery

(3)

16

(c) Name one drug that helps to prevent clotting

(1)

(Total 7 marks)

13 The chart below shows the number of deaths from cardiovascular disease per 100 000 population for men and women in four countries

Numberof

deathsper

100 000population

1000 ndash

800 ndash

600 ndash

400 ndash

200 ndash

0 ndash ndash ndash ndashndash

France Spain Englandand Wales

Russia

Women

Men

ndash

17

(a) Describe the differences in the death rates shown in the chart above

(3)

(b) One possible reason for the differences in the death rates due to cardiovascular disease between the different countries is the quantity of fruit and vegetables eaten

Write a suitable null hypothesis that could be tested by an epidemiologist investigating the effect of fruit and vegetable consumption on deaths from cardiovascular disease

(1)

(c) Suggest and explain two other reasons for the differences in the death rates between the countries due to cardiovascular disease

1

(2)

2

(2)

(Total 8 marks)

18

14 The diagram below shows the structure of the heart and some associated blood vessels

(a) Name the parts labelled A B and C

A

B

C (2)

19

(b) Describe how the structure of the left ventricle and the parts labelled B and C enable the left ventricle to carry out its function

(4)

(c) Many organs such as the uterus heart and kidneys of a pregnant woman use more oxygen than when she is not pregnant The graph below shows the increased usage of oxygen by these organs near the end of pregnancy as compared with the oxygen used before pregnancy

Uterus Heart Kidneys

8

7

6

5

4

3

2

1

0

Increase inoxygen used cm min3 ndash1

20

Suggest why the use of oxygen by each of the following organs increases during pregnancy

(i) Uterus

(ii) Heart

(4)

(Total 10 marks)

21

15 (a) Studies show that individuals who exercise regularly at 70 of their maximum heart rate significantly reduce their risk of cardiovascular disease Two reasons for this are that regular exercise reduces both the percentage body fat and the overall cholesterol level in blood plasma

(i) Describe the procedure for obtaining skinfold measurements to estimate percentage body fat

(4)

(ii) Explain why having high percentage body fat increases the risk of cardiovascular disease

(2)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

2

2 Coronary heart disease (CHD) is a major cause of death in developed countries and accounts for over 160 000 deaths each year in the United Kingdom One of the main causes of CHD is atherosclerosis a condition in which lipids and connective tissue build up on the inside wall of blood vessels

(a) State two consequences of atherosclerosis which may lead to the development of CHD in an individual

1

2

(2)

(b) The table shows deaths from coronary heart disease as a percentage of all deaths in the United Kingdom in 1983

Percentage of all deaths

Age years Males Females

0ndash14 4 3

15ndash24 7 10

25ndash34 15 14

35ndash44 37 18

45ndash54 53 26

55ndash64 53 37

65ndash74 53 50

75 and over 51 56

(i) Which two risk factors associated with the development of CHD are indicated in the table

(1)

3

(ii) With reference to the data in the table compare the percentage of deaths from CHD in males and females

(3)

(Total 6 marks)

3 The diagram below shows cross-sections of three different types of blood vessel A B and C

A B C

5 mm 5 mm 0005 mm

(a) Name the blood vessels A and B

A

B (1)

4

(b) State two ways in which blood vessel C is adapted to enable the formation of tissue fluid

1

2

(2)

(c) Give one function of tissue fluid

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(d) When tissue fluid is not efficiently reabsorbed it collects in tissues causing swelling (oedema) Suggest one factor that could cause oedema

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 5 marks)

4 The graph below shows changes in the blood pressure in the aorta and the left ventricle during two complete cardiac cycles

20

15

10

5

00 02 04 06 08 10 12 14 16 18

Time s

Pressure kPa Aortic pressure

Leftventricularpressure

(a) On the graph draw an arrow to show when the left atrioventricular (mitral) valve closes (1)

5

(b) Use the information in the graph to calculate the heart rate Show your working

Answer (2)

(c) During the cardiac cycle the pressure in the left ventricle falls to a much lower level than in the aorta Suggest an explanation for this difference

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helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(d) During the cardiac cycle the pressure in the right ventricle rises to a maximum of about 33 kPa Suggest reasons for the difference between this pressure and the maximum pressure in the left ventricle

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helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(Total 9 marks)

5 Explain what is meant by each of the following terms

6

(a) The cardiac cycle

(3)

(b) Coronary circulation

(3)

(Total 6 marks)

7

6 The diagram below shows an outline of the double circulation in a mammal

(a) Name the chambers of the heart labelled A and B

A

B (2)

(b) Name the organ in which the capillaries labelled C would be found

(1)

8

(c) The heart maintains a high pressure of oxygenated blood in the arteries to the body Explain how a double circulation is important in bringing this about

(3)

(d) The photomicrograph below shows a transverse section through blood vessels

(i) Give the names of the two types of blood vessel D and E

D

E (1)

9

(ii) Describe one characteristic feature that you used to identify D

(1)

(Total 8 marks)

7 The following information is taken from a web site promoting a margarine

Cholesterol in the body comes from two sources A small amount is eaten in certain foods but most is actually produced by our liver and we need some in our bodies to stay healthy The liver produces cholesterol when saturated fats are eaten Todayrsquos diet contains a lot of saturated fat and therefore the liver produces more cholesterol than the body actually requires To complicate matters there are two types of cholesterol ndash HDL (good) and LDL (bad) cholesterol

Our healthier margarine is a low fat spread enriched with plant sterols Plant sterols have been clinically proven to lower cholesterol levels by reducing the cholesterol being absorbed from the gut This helps to maintain a healthy heart

Independent clinical trials prove that moving to a diet that includes 20ndash25 g of healthier margarine per day gives average LDL cholesterol reductions of 10ndash15 There is no effect on HDL cholesterol If you eat less than this amount you will still see a reduction although it will not be as high as it could be Eating more will not give a significantly greater cholesterol lowering effect

(a) Give one way in which cholesterol in our bodies ensures that we lsquostay healthyrsquo

(1)

10

(b) Explain how high levels of LDL can affect the risk of heart disease

(4)

(c) Use information from the passage to suggest

(i) one way other than eating margarine in which blood cholesterol levels could be reduced by a change of diet

(1)

(ii) a reason why eating more than 20ndash25 g of healthier margarine a day lsquowill not give a significantly greater cholesterol lowering effectrsquo

(2)

(Total 8 marks)

11

8 (a) The table below refers to structural features of two types of blood vessels If the feature is correct place a tick ( ) in the appropriate box and if the feature is incorrect place a cross ( ) in the appropriate box

Blood vessel Structural feature

Valves present Wall has pores Wall a single layer of cells

Capillary

Vein (3)

(b) The wall of the aorta a major artery has many elastic fibres in it Suggest a reason for the presence of these fibres

(1)

(Total 4 marks)

9 (a) Describe three structural differences between arteries and veins

Arteries Veins

1

2

3

(3)

12

(b) Suggest why arteries are more likely than veins to develop atherosclerosis

(1)

(c) The diagram below shows how tissue fluid is formed from blood plasma

Describe and explain how fluid is forced out of the capillaries to form tissue fluid at the arterial end of the capillary

(2)

(d) (i) Give one reason why fluid might accumulate within the tissues and cause swelling

(1)

13

(ii) Name this type of swelling in the tissues

(1)

(Total 8 marks)

10 The composition of our diet may be associated with the development of disease in a number of our body organs Explain how diet may be associated with the development of the following diseases

Coronary heart disease (CHD)

(Total 3 marks)

11 The diagrams below show a pig (a mammal) and a flatworm (a small pond animal)

times005 times5

14

(a) Explain why a pig has a heart and circulatory system whereas a flatworm does not

(2)

(b) The diagram below shows a cross-section of a mammalian heart The positions of the valves are shown by the four circles

(i) On the diagram indicate whether each valve is open or closed during ventricular systole (contraction of the ventricles) by writing lsquoopenrsquo or lsquoclosedrsquo on the lines provided Do not draw the valves

(2)

(ii) Indicate the position of the sino-atrial node (pacemaker) by drawing a cross on the diagram

(1)

(iii) State the role of the sino-atrial node

(1)

15

(c) Suggest two advantages of the coronary artery branching directly off the aorta

1

2

(2)

(Total 8 marks)

12 (a) The diagram below summarises some of the steps involved in blood clotting Complete the diagram by writing in the missing words in the boxes

Thrombin

Fibrin

Thromboplastin released by damaged cells and

(3)

(b) Describe the possible effects of a blood clot forming in a coronary artery

(3)

16

(c) Name one drug that helps to prevent clotting

(1)

(Total 7 marks)

13 The chart below shows the number of deaths from cardiovascular disease per 100 000 population for men and women in four countries

Numberof

deathsper

100 000population

1000 ndash

800 ndash

600 ndash

400 ndash

200 ndash

0 ndash ndash ndash ndashndash

France Spain Englandand Wales

Russia

Women

Men

ndash

17

(a) Describe the differences in the death rates shown in the chart above

(3)

(b) One possible reason for the differences in the death rates due to cardiovascular disease between the different countries is the quantity of fruit and vegetables eaten

Write a suitable null hypothesis that could be tested by an epidemiologist investigating the effect of fruit and vegetable consumption on deaths from cardiovascular disease

(1)

(c) Suggest and explain two other reasons for the differences in the death rates between the countries due to cardiovascular disease

1

(2)

2

(2)

(Total 8 marks)

18

14 The diagram below shows the structure of the heart and some associated blood vessels

(a) Name the parts labelled A B and C

A

B

C (2)

19

(b) Describe how the structure of the left ventricle and the parts labelled B and C enable the left ventricle to carry out its function

(4)

(c) Many organs such as the uterus heart and kidneys of a pregnant woman use more oxygen than when she is not pregnant The graph below shows the increased usage of oxygen by these organs near the end of pregnancy as compared with the oxygen used before pregnancy

Uterus Heart Kidneys

8

7

6

5

4

3

2

1

0

Increase inoxygen used cm min3 ndash1

20

Suggest why the use of oxygen by each of the following organs increases during pregnancy

(i) Uterus

(ii) Heart

(4)

(Total 10 marks)

21

15 (a) Studies show that individuals who exercise regularly at 70 of their maximum heart rate significantly reduce their risk of cardiovascular disease Two reasons for this are that regular exercise reduces both the percentage body fat and the overall cholesterol level in blood plasma

(i) Describe the procedure for obtaining skinfold measurements to estimate percentage body fat

(4)

(ii) Explain why having high percentage body fat increases the risk of cardiovascular disease

(2)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

3

(ii) With reference to the data in the table compare the percentage of deaths from CHD in males and females

(3)

(Total 6 marks)

3 The diagram below shows cross-sections of three different types of blood vessel A B and C

A B C

5 mm 5 mm 0005 mm

(a) Name the blood vessels A and B

A

B (1)

4

(b) State two ways in which blood vessel C is adapted to enable the formation of tissue fluid

1

2

(2)

(c) Give one function of tissue fluid

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(d) When tissue fluid is not efficiently reabsorbed it collects in tissues causing swelling (oedema) Suggest one factor that could cause oedema

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 5 marks)

4 The graph below shows changes in the blood pressure in the aorta and the left ventricle during two complete cardiac cycles

20

15

10

5

00 02 04 06 08 10 12 14 16 18

Time s

Pressure kPa Aortic pressure

Leftventricularpressure

(a) On the graph draw an arrow to show when the left atrioventricular (mitral) valve closes (1)

5

(b) Use the information in the graph to calculate the heart rate Show your working

Answer (2)

(c) During the cardiac cycle the pressure in the left ventricle falls to a much lower level than in the aorta Suggest an explanation for this difference

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helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(d) During the cardiac cycle the pressure in the right ventricle rises to a maximum of about 33 kPa Suggest reasons for the difference between this pressure and the maximum pressure in the left ventricle

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helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(Total 9 marks)

5 Explain what is meant by each of the following terms

6

(a) The cardiac cycle

(3)

(b) Coronary circulation

(3)

(Total 6 marks)

7

6 The diagram below shows an outline of the double circulation in a mammal

(a) Name the chambers of the heart labelled A and B

A

B (2)

(b) Name the organ in which the capillaries labelled C would be found

(1)

8

(c) The heart maintains a high pressure of oxygenated blood in the arteries to the body Explain how a double circulation is important in bringing this about

(3)

(d) The photomicrograph below shows a transverse section through blood vessels

(i) Give the names of the two types of blood vessel D and E

D

E (1)

9

(ii) Describe one characteristic feature that you used to identify D

(1)

(Total 8 marks)

7 The following information is taken from a web site promoting a margarine

Cholesterol in the body comes from two sources A small amount is eaten in certain foods but most is actually produced by our liver and we need some in our bodies to stay healthy The liver produces cholesterol when saturated fats are eaten Todayrsquos diet contains a lot of saturated fat and therefore the liver produces more cholesterol than the body actually requires To complicate matters there are two types of cholesterol ndash HDL (good) and LDL (bad) cholesterol

Our healthier margarine is a low fat spread enriched with plant sterols Plant sterols have been clinically proven to lower cholesterol levels by reducing the cholesterol being absorbed from the gut This helps to maintain a healthy heart

Independent clinical trials prove that moving to a diet that includes 20ndash25 g of healthier margarine per day gives average LDL cholesterol reductions of 10ndash15 There is no effect on HDL cholesterol If you eat less than this amount you will still see a reduction although it will not be as high as it could be Eating more will not give a significantly greater cholesterol lowering effect

(a) Give one way in which cholesterol in our bodies ensures that we lsquostay healthyrsquo

(1)

10

(b) Explain how high levels of LDL can affect the risk of heart disease

(4)

(c) Use information from the passage to suggest

(i) one way other than eating margarine in which blood cholesterol levels could be reduced by a change of diet

(1)

(ii) a reason why eating more than 20ndash25 g of healthier margarine a day lsquowill not give a significantly greater cholesterol lowering effectrsquo

(2)

(Total 8 marks)

11

8 (a) The table below refers to structural features of two types of blood vessels If the feature is correct place a tick ( ) in the appropriate box and if the feature is incorrect place a cross ( ) in the appropriate box

Blood vessel Structural feature

Valves present Wall has pores Wall a single layer of cells

Capillary

Vein (3)

(b) The wall of the aorta a major artery has many elastic fibres in it Suggest a reason for the presence of these fibres

(1)

(Total 4 marks)

9 (a) Describe three structural differences between arteries and veins

Arteries Veins

1

2

3

(3)

12

(b) Suggest why arteries are more likely than veins to develop atherosclerosis

(1)

(c) The diagram below shows how tissue fluid is formed from blood plasma

Describe and explain how fluid is forced out of the capillaries to form tissue fluid at the arterial end of the capillary

(2)

(d) (i) Give one reason why fluid might accumulate within the tissues and cause swelling

(1)

13

(ii) Name this type of swelling in the tissues

(1)

(Total 8 marks)

10 The composition of our diet may be associated with the development of disease in a number of our body organs Explain how diet may be associated with the development of the following diseases

Coronary heart disease (CHD)

(Total 3 marks)

11 The diagrams below show a pig (a mammal) and a flatworm (a small pond animal)

times005 times5

14

(a) Explain why a pig has a heart and circulatory system whereas a flatworm does not

(2)

(b) The diagram below shows a cross-section of a mammalian heart The positions of the valves are shown by the four circles

(i) On the diagram indicate whether each valve is open or closed during ventricular systole (contraction of the ventricles) by writing lsquoopenrsquo or lsquoclosedrsquo on the lines provided Do not draw the valves

(2)

(ii) Indicate the position of the sino-atrial node (pacemaker) by drawing a cross on the diagram

(1)

(iii) State the role of the sino-atrial node

(1)

15

(c) Suggest two advantages of the coronary artery branching directly off the aorta

1

2

(2)

(Total 8 marks)

12 (a) The diagram below summarises some of the steps involved in blood clotting Complete the diagram by writing in the missing words in the boxes

Thrombin

Fibrin

Thromboplastin released by damaged cells and

(3)

(b) Describe the possible effects of a blood clot forming in a coronary artery

(3)

16

(c) Name one drug that helps to prevent clotting

(1)

(Total 7 marks)

13 The chart below shows the number of deaths from cardiovascular disease per 100 000 population for men and women in four countries

Numberof

deathsper

100 000population

1000 ndash

800 ndash

600 ndash

400 ndash

200 ndash

0 ndash ndash ndash ndashndash

France Spain Englandand Wales

Russia

Women

Men

ndash

17

(a) Describe the differences in the death rates shown in the chart above

(3)

(b) One possible reason for the differences in the death rates due to cardiovascular disease between the different countries is the quantity of fruit and vegetables eaten

Write a suitable null hypothesis that could be tested by an epidemiologist investigating the effect of fruit and vegetable consumption on deaths from cardiovascular disease

(1)

(c) Suggest and explain two other reasons for the differences in the death rates between the countries due to cardiovascular disease

1

(2)

2

(2)

(Total 8 marks)

18

14 The diagram below shows the structure of the heart and some associated blood vessels

(a) Name the parts labelled A B and C

A

B

C (2)

19

(b) Describe how the structure of the left ventricle and the parts labelled B and C enable the left ventricle to carry out its function

(4)

(c) Many organs such as the uterus heart and kidneys of a pregnant woman use more oxygen than when she is not pregnant The graph below shows the increased usage of oxygen by these organs near the end of pregnancy as compared with the oxygen used before pregnancy

Uterus Heart Kidneys

8

7

6

5

4

3

2

1

0

Increase inoxygen used cm min3 ndash1

20

Suggest why the use of oxygen by each of the following organs increases during pregnancy

(i) Uterus

(ii) Heart

(4)

(Total 10 marks)

21

15 (a) Studies show that individuals who exercise regularly at 70 of their maximum heart rate significantly reduce their risk of cardiovascular disease Two reasons for this are that regular exercise reduces both the percentage body fat and the overall cholesterol level in blood plasma

(i) Describe the procedure for obtaining skinfold measurements to estimate percentage body fat

(4)

(ii) Explain why having high percentage body fat increases the risk of cardiovascular disease

(2)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

4

(b) State two ways in which blood vessel C is adapted to enable the formation of tissue fluid

1

2

(2)

(c) Give one function of tissue fluid

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(d) When tissue fluid is not efficiently reabsorbed it collects in tissues causing swelling (oedema) Suggest one factor that could cause oedema

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 5 marks)

4 The graph below shows changes in the blood pressure in the aorta and the left ventricle during two complete cardiac cycles

20

15

10

5

00 02 04 06 08 10 12 14 16 18

Time s

Pressure kPa Aortic pressure

Leftventricularpressure

(a) On the graph draw an arrow to show when the left atrioventricular (mitral) valve closes (1)

5

(b) Use the information in the graph to calculate the heart rate Show your working

Answer (2)

(c) During the cardiac cycle the pressure in the left ventricle falls to a much lower level than in the aorta Suggest an explanation for this difference

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helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(d) During the cardiac cycle the pressure in the right ventricle rises to a maximum of about 33 kPa Suggest reasons for the difference between this pressure and the maximum pressure in the left ventricle

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helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(Total 9 marks)

5 Explain what is meant by each of the following terms

6

(a) The cardiac cycle

(3)

(b) Coronary circulation

(3)

(Total 6 marks)

7

6 The diagram below shows an outline of the double circulation in a mammal

(a) Name the chambers of the heart labelled A and B

A

B (2)

(b) Name the organ in which the capillaries labelled C would be found

(1)

8

(c) The heart maintains a high pressure of oxygenated blood in the arteries to the body Explain how a double circulation is important in bringing this about

(3)

(d) The photomicrograph below shows a transverse section through blood vessels

(i) Give the names of the two types of blood vessel D and E

D

E (1)

9

(ii) Describe one characteristic feature that you used to identify D

(1)

(Total 8 marks)

7 The following information is taken from a web site promoting a margarine

Cholesterol in the body comes from two sources A small amount is eaten in certain foods but most is actually produced by our liver and we need some in our bodies to stay healthy The liver produces cholesterol when saturated fats are eaten Todayrsquos diet contains a lot of saturated fat and therefore the liver produces more cholesterol than the body actually requires To complicate matters there are two types of cholesterol ndash HDL (good) and LDL (bad) cholesterol

Our healthier margarine is a low fat spread enriched with plant sterols Plant sterols have been clinically proven to lower cholesterol levels by reducing the cholesterol being absorbed from the gut This helps to maintain a healthy heart

Independent clinical trials prove that moving to a diet that includes 20ndash25 g of healthier margarine per day gives average LDL cholesterol reductions of 10ndash15 There is no effect on HDL cholesterol If you eat less than this amount you will still see a reduction although it will not be as high as it could be Eating more will not give a significantly greater cholesterol lowering effect

(a) Give one way in which cholesterol in our bodies ensures that we lsquostay healthyrsquo

(1)

10

(b) Explain how high levels of LDL can affect the risk of heart disease

(4)

(c) Use information from the passage to suggest

(i) one way other than eating margarine in which blood cholesterol levels could be reduced by a change of diet

(1)

(ii) a reason why eating more than 20ndash25 g of healthier margarine a day lsquowill not give a significantly greater cholesterol lowering effectrsquo

(2)

(Total 8 marks)

11

8 (a) The table below refers to structural features of two types of blood vessels If the feature is correct place a tick ( ) in the appropriate box and if the feature is incorrect place a cross ( ) in the appropriate box

Blood vessel Structural feature

Valves present Wall has pores Wall a single layer of cells

Capillary

Vein (3)

(b) The wall of the aorta a major artery has many elastic fibres in it Suggest a reason for the presence of these fibres

(1)

(Total 4 marks)

9 (a) Describe three structural differences between arteries and veins

Arteries Veins

1

2

3

(3)

12

(b) Suggest why arteries are more likely than veins to develop atherosclerosis

(1)

(c) The diagram below shows how tissue fluid is formed from blood plasma

Describe and explain how fluid is forced out of the capillaries to form tissue fluid at the arterial end of the capillary

(2)

(d) (i) Give one reason why fluid might accumulate within the tissues and cause swelling

(1)

13

(ii) Name this type of swelling in the tissues

(1)

(Total 8 marks)

10 The composition of our diet may be associated with the development of disease in a number of our body organs Explain how diet may be associated with the development of the following diseases

Coronary heart disease (CHD)

(Total 3 marks)

11 The diagrams below show a pig (a mammal) and a flatworm (a small pond animal)

times005 times5

14

(a) Explain why a pig has a heart and circulatory system whereas a flatworm does not

(2)

(b) The diagram below shows a cross-section of a mammalian heart The positions of the valves are shown by the four circles

(i) On the diagram indicate whether each valve is open or closed during ventricular systole (contraction of the ventricles) by writing lsquoopenrsquo or lsquoclosedrsquo on the lines provided Do not draw the valves

(2)

(ii) Indicate the position of the sino-atrial node (pacemaker) by drawing a cross on the diagram

(1)

(iii) State the role of the sino-atrial node

(1)

15

(c) Suggest two advantages of the coronary artery branching directly off the aorta

1

2

(2)

(Total 8 marks)

12 (a) The diagram below summarises some of the steps involved in blood clotting Complete the diagram by writing in the missing words in the boxes

Thrombin

Fibrin

Thromboplastin released by damaged cells and

(3)

(b) Describe the possible effects of a blood clot forming in a coronary artery

(3)

16

(c) Name one drug that helps to prevent clotting

(1)

(Total 7 marks)

13 The chart below shows the number of deaths from cardiovascular disease per 100 000 population for men and women in four countries

Numberof

deathsper

100 000population

1000 ndash

800 ndash

600 ndash

400 ndash

200 ndash

0 ndash ndash ndash ndashndash

France Spain Englandand Wales

Russia

Women

Men

ndash

17

(a) Describe the differences in the death rates shown in the chart above

(3)

(b) One possible reason for the differences in the death rates due to cardiovascular disease between the different countries is the quantity of fruit and vegetables eaten

Write a suitable null hypothesis that could be tested by an epidemiologist investigating the effect of fruit and vegetable consumption on deaths from cardiovascular disease

(1)

(c) Suggest and explain two other reasons for the differences in the death rates between the countries due to cardiovascular disease

1

(2)

2

(2)

(Total 8 marks)

18

14 The diagram below shows the structure of the heart and some associated blood vessels

(a) Name the parts labelled A B and C

A

B

C (2)

19

(b) Describe how the structure of the left ventricle and the parts labelled B and C enable the left ventricle to carry out its function

(4)

(c) Many organs such as the uterus heart and kidneys of a pregnant woman use more oxygen than when she is not pregnant The graph below shows the increased usage of oxygen by these organs near the end of pregnancy as compared with the oxygen used before pregnancy

Uterus Heart Kidneys

8

7

6

5

4

3

2

1

0

Increase inoxygen used cm min3 ndash1

20

Suggest why the use of oxygen by each of the following organs increases during pregnancy

(i) Uterus

(ii) Heart

(4)

(Total 10 marks)

21

15 (a) Studies show that individuals who exercise regularly at 70 of their maximum heart rate significantly reduce their risk of cardiovascular disease Two reasons for this are that regular exercise reduces both the percentage body fat and the overall cholesterol level in blood plasma

(i) Describe the procedure for obtaining skinfold measurements to estimate percentage body fat

(4)

(ii) Explain why having high percentage body fat increases the risk of cardiovascular disease

(2)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

5

(b) Use the information in the graph to calculate the heart rate Show your working

Answer (2)

(c) During the cardiac cycle the pressure in the left ventricle falls to a much lower level than in the aorta Suggest an explanation for this difference

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helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(d) During the cardiac cycle the pressure in the right ventricle rises to a maximum of about 33 kPa Suggest reasons for the difference between this pressure and the maximum pressure in the left ventricle

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helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(Total 9 marks)

5 Explain what is meant by each of the following terms

6

(a) The cardiac cycle

(3)

(b) Coronary circulation

(3)

(Total 6 marks)

7

6 The diagram below shows an outline of the double circulation in a mammal

(a) Name the chambers of the heart labelled A and B

A

B (2)

(b) Name the organ in which the capillaries labelled C would be found

(1)

8

(c) The heart maintains a high pressure of oxygenated blood in the arteries to the body Explain how a double circulation is important in bringing this about

(3)

(d) The photomicrograph below shows a transverse section through blood vessels

(i) Give the names of the two types of blood vessel D and E

D

E (1)

9

(ii) Describe one characteristic feature that you used to identify D

(1)

(Total 8 marks)

7 The following information is taken from a web site promoting a margarine

Cholesterol in the body comes from two sources A small amount is eaten in certain foods but most is actually produced by our liver and we need some in our bodies to stay healthy The liver produces cholesterol when saturated fats are eaten Todayrsquos diet contains a lot of saturated fat and therefore the liver produces more cholesterol than the body actually requires To complicate matters there are two types of cholesterol ndash HDL (good) and LDL (bad) cholesterol

Our healthier margarine is a low fat spread enriched with plant sterols Plant sterols have been clinically proven to lower cholesterol levels by reducing the cholesterol being absorbed from the gut This helps to maintain a healthy heart

Independent clinical trials prove that moving to a diet that includes 20ndash25 g of healthier margarine per day gives average LDL cholesterol reductions of 10ndash15 There is no effect on HDL cholesterol If you eat less than this amount you will still see a reduction although it will not be as high as it could be Eating more will not give a significantly greater cholesterol lowering effect

(a) Give one way in which cholesterol in our bodies ensures that we lsquostay healthyrsquo

(1)

10

(b) Explain how high levels of LDL can affect the risk of heart disease

(4)

(c) Use information from the passage to suggest

(i) one way other than eating margarine in which blood cholesterol levels could be reduced by a change of diet

(1)

(ii) a reason why eating more than 20ndash25 g of healthier margarine a day lsquowill not give a significantly greater cholesterol lowering effectrsquo

(2)

(Total 8 marks)

11

8 (a) The table below refers to structural features of two types of blood vessels If the feature is correct place a tick ( ) in the appropriate box and if the feature is incorrect place a cross ( ) in the appropriate box

Blood vessel Structural feature

Valves present Wall has pores Wall a single layer of cells

Capillary

Vein (3)

(b) The wall of the aorta a major artery has many elastic fibres in it Suggest a reason for the presence of these fibres

(1)

(Total 4 marks)

9 (a) Describe three structural differences between arteries and veins

Arteries Veins

1

2

3

(3)

12

(b) Suggest why arteries are more likely than veins to develop atherosclerosis

(1)

(c) The diagram below shows how tissue fluid is formed from blood plasma

Describe and explain how fluid is forced out of the capillaries to form tissue fluid at the arterial end of the capillary

(2)

(d) (i) Give one reason why fluid might accumulate within the tissues and cause swelling

(1)

13

(ii) Name this type of swelling in the tissues

(1)

(Total 8 marks)

10 The composition of our diet may be associated with the development of disease in a number of our body organs Explain how diet may be associated with the development of the following diseases

Coronary heart disease (CHD)

(Total 3 marks)

11 The diagrams below show a pig (a mammal) and a flatworm (a small pond animal)

times005 times5

14

(a) Explain why a pig has a heart and circulatory system whereas a flatworm does not

(2)

(b) The diagram below shows a cross-section of a mammalian heart The positions of the valves are shown by the four circles

(i) On the diagram indicate whether each valve is open or closed during ventricular systole (contraction of the ventricles) by writing lsquoopenrsquo or lsquoclosedrsquo on the lines provided Do not draw the valves

(2)

(ii) Indicate the position of the sino-atrial node (pacemaker) by drawing a cross on the diagram

(1)

(iii) State the role of the sino-atrial node

(1)

15

(c) Suggest two advantages of the coronary artery branching directly off the aorta

1

2

(2)

(Total 8 marks)

12 (a) The diagram below summarises some of the steps involved in blood clotting Complete the diagram by writing in the missing words in the boxes

Thrombin

Fibrin

Thromboplastin released by damaged cells and

(3)

(b) Describe the possible effects of a blood clot forming in a coronary artery

(3)

16

(c) Name one drug that helps to prevent clotting

(1)

(Total 7 marks)

13 The chart below shows the number of deaths from cardiovascular disease per 100 000 population for men and women in four countries

Numberof

deathsper

100 000population

1000 ndash

800 ndash

600 ndash

400 ndash

200 ndash

0 ndash ndash ndash ndashndash

France Spain Englandand Wales

Russia

Women

Men

ndash

17

(a) Describe the differences in the death rates shown in the chart above

(3)

(b) One possible reason for the differences in the death rates due to cardiovascular disease between the different countries is the quantity of fruit and vegetables eaten

Write a suitable null hypothesis that could be tested by an epidemiologist investigating the effect of fruit and vegetable consumption on deaths from cardiovascular disease

(1)

(c) Suggest and explain two other reasons for the differences in the death rates between the countries due to cardiovascular disease

1

(2)

2

(2)

(Total 8 marks)

18

14 The diagram below shows the structure of the heart and some associated blood vessels

(a) Name the parts labelled A B and C

A

B

C (2)

19

(b) Describe how the structure of the left ventricle and the parts labelled B and C enable the left ventricle to carry out its function

(4)

(c) Many organs such as the uterus heart and kidneys of a pregnant woman use more oxygen than when she is not pregnant The graph below shows the increased usage of oxygen by these organs near the end of pregnancy as compared with the oxygen used before pregnancy

Uterus Heart Kidneys

8

7

6

5

4

3

2

1

0

Increase inoxygen used cm min3 ndash1

20

Suggest why the use of oxygen by each of the following organs increases during pregnancy

(i) Uterus

(ii) Heart

(4)

(Total 10 marks)

21

15 (a) Studies show that individuals who exercise regularly at 70 of their maximum heart rate significantly reduce their risk of cardiovascular disease Two reasons for this are that regular exercise reduces both the percentage body fat and the overall cholesterol level in blood plasma

(i) Describe the procedure for obtaining skinfold measurements to estimate percentage body fat

(4)

(ii) Explain why having high percentage body fat increases the risk of cardiovascular disease

(2)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

6

(a) The cardiac cycle

(3)

(b) Coronary circulation

(3)

(Total 6 marks)

7

6 The diagram below shows an outline of the double circulation in a mammal

(a) Name the chambers of the heart labelled A and B

A

B (2)

(b) Name the organ in which the capillaries labelled C would be found

(1)

8

(c) The heart maintains a high pressure of oxygenated blood in the arteries to the body Explain how a double circulation is important in bringing this about

(3)

(d) The photomicrograph below shows a transverse section through blood vessels

(i) Give the names of the two types of blood vessel D and E

D

E (1)

9

(ii) Describe one characteristic feature that you used to identify D

(1)

(Total 8 marks)

7 The following information is taken from a web site promoting a margarine

Cholesterol in the body comes from two sources A small amount is eaten in certain foods but most is actually produced by our liver and we need some in our bodies to stay healthy The liver produces cholesterol when saturated fats are eaten Todayrsquos diet contains a lot of saturated fat and therefore the liver produces more cholesterol than the body actually requires To complicate matters there are two types of cholesterol ndash HDL (good) and LDL (bad) cholesterol

Our healthier margarine is a low fat spread enriched with plant sterols Plant sterols have been clinically proven to lower cholesterol levels by reducing the cholesterol being absorbed from the gut This helps to maintain a healthy heart

Independent clinical trials prove that moving to a diet that includes 20ndash25 g of healthier margarine per day gives average LDL cholesterol reductions of 10ndash15 There is no effect on HDL cholesterol If you eat less than this amount you will still see a reduction although it will not be as high as it could be Eating more will not give a significantly greater cholesterol lowering effect

(a) Give one way in which cholesterol in our bodies ensures that we lsquostay healthyrsquo

(1)

10

(b) Explain how high levels of LDL can affect the risk of heart disease

(4)

(c) Use information from the passage to suggest

(i) one way other than eating margarine in which blood cholesterol levels could be reduced by a change of diet

(1)

(ii) a reason why eating more than 20ndash25 g of healthier margarine a day lsquowill not give a significantly greater cholesterol lowering effectrsquo

(2)

(Total 8 marks)

11

8 (a) The table below refers to structural features of two types of blood vessels If the feature is correct place a tick ( ) in the appropriate box and if the feature is incorrect place a cross ( ) in the appropriate box

Blood vessel Structural feature

Valves present Wall has pores Wall a single layer of cells

Capillary

Vein (3)

(b) The wall of the aorta a major artery has many elastic fibres in it Suggest a reason for the presence of these fibres

(1)

(Total 4 marks)

9 (a) Describe three structural differences between arteries and veins

Arteries Veins

1

2

3

(3)

12

(b) Suggest why arteries are more likely than veins to develop atherosclerosis

(1)

(c) The diagram below shows how tissue fluid is formed from blood plasma

Describe and explain how fluid is forced out of the capillaries to form tissue fluid at the arterial end of the capillary

(2)

(d) (i) Give one reason why fluid might accumulate within the tissues and cause swelling

(1)

13

(ii) Name this type of swelling in the tissues

(1)

(Total 8 marks)

10 The composition of our diet may be associated with the development of disease in a number of our body organs Explain how diet may be associated with the development of the following diseases

Coronary heart disease (CHD)

(Total 3 marks)

11 The diagrams below show a pig (a mammal) and a flatworm (a small pond animal)

times005 times5

14

(a) Explain why a pig has a heart and circulatory system whereas a flatworm does not

(2)

(b) The diagram below shows a cross-section of a mammalian heart The positions of the valves are shown by the four circles

(i) On the diagram indicate whether each valve is open or closed during ventricular systole (contraction of the ventricles) by writing lsquoopenrsquo or lsquoclosedrsquo on the lines provided Do not draw the valves

(2)

(ii) Indicate the position of the sino-atrial node (pacemaker) by drawing a cross on the diagram

(1)

(iii) State the role of the sino-atrial node

(1)

15

(c) Suggest two advantages of the coronary artery branching directly off the aorta

1

2

(2)

(Total 8 marks)

12 (a) The diagram below summarises some of the steps involved in blood clotting Complete the diagram by writing in the missing words in the boxes

Thrombin

Fibrin

Thromboplastin released by damaged cells and

(3)

(b) Describe the possible effects of a blood clot forming in a coronary artery

(3)

16

(c) Name one drug that helps to prevent clotting

(1)

(Total 7 marks)

13 The chart below shows the number of deaths from cardiovascular disease per 100 000 population for men and women in four countries

Numberof

deathsper

100 000population

1000 ndash

800 ndash

600 ndash

400 ndash

200 ndash

0 ndash ndash ndash ndashndash

France Spain Englandand Wales

Russia

Women

Men

ndash

17

(a) Describe the differences in the death rates shown in the chart above

(3)

(b) One possible reason for the differences in the death rates due to cardiovascular disease between the different countries is the quantity of fruit and vegetables eaten

Write a suitable null hypothesis that could be tested by an epidemiologist investigating the effect of fruit and vegetable consumption on deaths from cardiovascular disease

(1)

(c) Suggest and explain two other reasons for the differences in the death rates between the countries due to cardiovascular disease

1

(2)

2

(2)

(Total 8 marks)

18

14 The diagram below shows the structure of the heart and some associated blood vessels

(a) Name the parts labelled A B and C

A

B

C (2)

19

(b) Describe how the structure of the left ventricle and the parts labelled B and C enable the left ventricle to carry out its function

(4)

(c) Many organs such as the uterus heart and kidneys of a pregnant woman use more oxygen than when she is not pregnant The graph below shows the increased usage of oxygen by these organs near the end of pregnancy as compared with the oxygen used before pregnancy

Uterus Heart Kidneys

8

7

6

5

4

3

2

1

0

Increase inoxygen used cm min3 ndash1

20

Suggest why the use of oxygen by each of the following organs increases during pregnancy

(i) Uterus

(ii) Heart

(4)

(Total 10 marks)

21

15 (a) Studies show that individuals who exercise regularly at 70 of their maximum heart rate significantly reduce their risk of cardiovascular disease Two reasons for this are that regular exercise reduces both the percentage body fat and the overall cholesterol level in blood plasma

(i) Describe the procedure for obtaining skinfold measurements to estimate percentage body fat

(4)

(ii) Explain why having high percentage body fat increases the risk of cardiovascular disease

(2)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

7

6 The diagram below shows an outline of the double circulation in a mammal

(a) Name the chambers of the heart labelled A and B

A

B (2)

(b) Name the organ in which the capillaries labelled C would be found

(1)

8

(c) The heart maintains a high pressure of oxygenated blood in the arteries to the body Explain how a double circulation is important in bringing this about

(3)

(d) The photomicrograph below shows a transverse section through blood vessels

(i) Give the names of the two types of blood vessel D and E

D

E (1)

9

(ii) Describe one characteristic feature that you used to identify D

(1)

(Total 8 marks)

7 The following information is taken from a web site promoting a margarine

Cholesterol in the body comes from two sources A small amount is eaten in certain foods but most is actually produced by our liver and we need some in our bodies to stay healthy The liver produces cholesterol when saturated fats are eaten Todayrsquos diet contains a lot of saturated fat and therefore the liver produces more cholesterol than the body actually requires To complicate matters there are two types of cholesterol ndash HDL (good) and LDL (bad) cholesterol

Our healthier margarine is a low fat spread enriched with plant sterols Plant sterols have been clinically proven to lower cholesterol levels by reducing the cholesterol being absorbed from the gut This helps to maintain a healthy heart

Independent clinical trials prove that moving to a diet that includes 20ndash25 g of healthier margarine per day gives average LDL cholesterol reductions of 10ndash15 There is no effect on HDL cholesterol If you eat less than this amount you will still see a reduction although it will not be as high as it could be Eating more will not give a significantly greater cholesterol lowering effect

(a) Give one way in which cholesterol in our bodies ensures that we lsquostay healthyrsquo

(1)

10

(b) Explain how high levels of LDL can affect the risk of heart disease

(4)

(c) Use information from the passage to suggest

(i) one way other than eating margarine in which blood cholesterol levels could be reduced by a change of diet

(1)

(ii) a reason why eating more than 20ndash25 g of healthier margarine a day lsquowill not give a significantly greater cholesterol lowering effectrsquo

(2)

(Total 8 marks)

11

8 (a) The table below refers to structural features of two types of blood vessels If the feature is correct place a tick ( ) in the appropriate box and if the feature is incorrect place a cross ( ) in the appropriate box

Blood vessel Structural feature

Valves present Wall has pores Wall a single layer of cells

Capillary

Vein (3)

(b) The wall of the aorta a major artery has many elastic fibres in it Suggest a reason for the presence of these fibres

(1)

(Total 4 marks)

9 (a) Describe three structural differences between arteries and veins

Arteries Veins

1

2

3

(3)

12

(b) Suggest why arteries are more likely than veins to develop atherosclerosis

(1)

(c) The diagram below shows how tissue fluid is formed from blood plasma

Describe and explain how fluid is forced out of the capillaries to form tissue fluid at the arterial end of the capillary

(2)

(d) (i) Give one reason why fluid might accumulate within the tissues and cause swelling

(1)

13

(ii) Name this type of swelling in the tissues

(1)

(Total 8 marks)

10 The composition of our diet may be associated with the development of disease in a number of our body organs Explain how diet may be associated with the development of the following diseases

Coronary heart disease (CHD)

(Total 3 marks)

11 The diagrams below show a pig (a mammal) and a flatworm (a small pond animal)

times005 times5

14

(a) Explain why a pig has a heart and circulatory system whereas a flatworm does not

(2)

(b) The diagram below shows a cross-section of a mammalian heart The positions of the valves are shown by the four circles

(i) On the diagram indicate whether each valve is open or closed during ventricular systole (contraction of the ventricles) by writing lsquoopenrsquo or lsquoclosedrsquo on the lines provided Do not draw the valves

(2)

(ii) Indicate the position of the sino-atrial node (pacemaker) by drawing a cross on the diagram

(1)

(iii) State the role of the sino-atrial node

(1)

15

(c) Suggest two advantages of the coronary artery branching directly off the aorta

1

2

(2)

(Total 8 marks)

12 (a) The diagram below summarises some of the steps involved in blood clotting Complete the diagram by writing in the missing words in the boxes

Thrombin

Fibrin

Thromboplastin released by damaged cells and

(3)

(b) Describe the possible effects of a blood clot forming in a coronary artery

(3)

16

(c) Name one drug that helps to prevent clotting

(1)

(Total 7 marks)

13 The chart below shows the number of deaths from cardiovascular disease per 100 000 population for men and women in four countries

Numberof

deathsper

100 000population

1000 ndash

800 ndash

600 ndash

400 ndash

200 ndash

0 ndash ndash ndash ndashndash

France Spain Englandand Wales

Russia

Women

Men

ndash

17

(a) Describe the differences in the death rates shown in the chart above

(3)

(b) One possible reason for the differences in the death rates due to cardiovascular disease between the different countries is the quantity of fruit and vegetables eaten

Write a suitable null hypothesis that could be tested by an epidemiologist investigating the effect of fruit and vegetable consumption on deaths from cardiovascular disease

(1)

(c) Suggest and explain two other reasons for the differences in the death rates between the countries due to cardiovascular disease

1

(2)

2

(2)

(Total 8 marks)

18

14 The diagram below shows the structure of the heart and some associated blood vessels

(a) Name the parts labelled A B and C

A

B

C (2)

19

(b) Describe how the structure of the left ventricle and the parts labelled B and C enable the left ventricle to carry out its function

(4)

(c) Many organs such as the uterus heart and kidneys of a pregnant woman use more oxygen than when she is not pregnant The graph below shows the increased usage of oxygen by these organs near the end of pregnancy as compared with the oxygen used before pregnancy

Uterus Heart Kidneys

8

7

6

5

4

3

2

1

0

Increase inoxygen used cm min3 ndash1

20

Suggest why the use of oxygen by each of the following organs increases during pregnancy

(i) Uterus

(ii) Heart

(4)

(Total 10 marks)

21

15 (a) Studies show that individuals who exercise regularly at 70 of their maximum heart rate significantly reduce their risk of cardiovascular disease Two reasons for this are that regular exercise reduces both the percentage body fat and the overall cholesterol level in blood plasma

(i) Describe the procedure for obtaining skinfold measurements to estimate percentage body fat

(4)

(ii) Explain why having high percentage body fat increases the risk of cardiovascular disease

(2)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

8

(c) The heart maintains a high pressure of oxygenated blood in the arteries to the body Explain how a double circulation is important in bringing this about

(3)

(d) The photomicrograph below shows a transverse section through blood vessels

(i) Give the names of the two types of blood vessel D and E

D

E (1)

9

(ii) Describe one characteristic feature that you used to identify D

(1)

(Total 8 marks)

7 The following information is taken from a web site promoting a margarine

Cholesterol in the body comes from two sources A small amount is eaten in certain foods but most is actually produced by our liver and we need some in our bodies to stay healthy The liver produces cholesterol when saturated fats are eaten Todayrsquos diet contains a lot of saturated fat and therefore the liver produces more cholesterol than the body actually requires To complicate matters there are two types of cholesterol ndash HDL (good) and LDL (bad) cholesterol

Our healthier margarine is a low fat spread enriched with plant sterols Plant sterols have been clinically proven to lower cholesterol levels by reducing the cholesterol being absorbed from the gut This helps to maintain a healthy heart

Independent clinical trials prove that moving to a diet that includes 20ndash25 g of healthier margarine per day gives average LDL cholesterol reductions of 10ndash15 There is no effect on HDL cholesterol If you eat less than this amount you will still see a reduction although it will not be as high as it could be Eating more will not give a significantly greater cholesterol lowering effect

(a) Give one way in which cholesterol in our bodies ensures that we lsquostay healthyrsquo

(1)

10

(b) Explain how high levels of LDL can affect the risk of heart disease

(4)

(c) Use information from the passage to suggest

(i) one way other than eating margarine in which blood cholesterol levels could be reduced by a change of diet

(1)

(ii) a reason why eating more than 20ndash25 g of healthier margarine a day lsquowill not give a significantly greater cholesterol lowering effectrsquo

(2)

(Total 8 marks)

11

8 (a) The table below refers to structural features of two types of blood vessels If the feature is correct place a tick ( ) in the appropriate box and if the feature is incorrect place a cross ( ) in the appropriate box

Blood vessel Structural feature

Valves present Wall has pores Wall a single layer of cells

Capillary

Vein (3)

(b) The wall of the aorta a major artery has many elastic fibres in it Suggest a reason for the presence of these fibres

(1)

(Total 4 marks)

9 (a) Describe three structural differences between arteries and veins

Arteries Veins

1

2

3

(3)

12

(b) Suggest why arteries are more likely than veins to develop atherosclerosis

(1)

(c) The diagram below shows how tissue fluid is formed from blood plasma

Describe and explain how fluid is forced out of the capillaries to form tissue fluid at the arterial end of the capillary

(2)

(d) (i) Give one reason why fluid might accumulate within the tissues and cause swelling

(1)

13

(ii) Name this type of swelling in the tissues

(1)

(Total 8 marks)

10 The composition of our diet may be associated with the development of disease in a number of our body organs Explain how diet may be associated with the development of the following diseases

Coronary heart disease (CHD)

(Total 3 marks)

11 The diagrams below show a pig (a mammal) and a flatworm (a small pond animal)

times005 times5

14

(a) Explain why a pig has a heart and circulatory system whereas a flatworm does not

(2)

(b) The diagram below shows a cross-section of a mammalian heart The positions of the valves are shown by the four circles

(i) On the diagram indicate whether each valve is open or closed during ventricular systole (contraction of the ventricles) by writing lsquoopenrsquo or lsquoclosedrsquo on the lines provided Do not draw the valves

(2)

(ii) Indicate the position of the sino-atrial node (pacemaker) by drawing a cross on the diagram

(1)

(iii) State the role of the sino-atrial node

(1)

15

(c) Suggest two advantages of the coronary artery branching directly off the aorta

1

2

(2)

(Total 8 marks)

12 (a) The diagram below summarises some of the steps involved in blood clotting Complete the diagram by writing in the missing words in the boxes

Thrombin

Fibrin

Thromboplastin released by damaged cells and

(3)

(b) Describe the possible effects of a blood clot forming in a coronary artery

(3)

16

(c) Name one drug that helps to prevent clotting

(1)

(Total 7 marks)

13 The chart below shows the number of deaths from cardiovascular disease per 100 000 population for men and women in four countries

Numberof

deathsper

100 000population

1000 ndash

800 ndash

600 ndash

400 ndash

200 ndash

0 ndash ndash ndash ndashndash

France Spain Englandand Wales

Russia

Women

Men

ndash

17

(a) Describe the differences in the death rates shown in the chart above

(3)

(b) One possible reason for the differences in the death rates due to cardiovascular disease between the different countries is the quantity of fruit and vegetables eaten

Write a suitable null hypothesis that could be tested by an epidemiologist investigating the effect of fruit and vegetable consumption on deaths from cardiovascular disease

(1)

(c) Suggest and explain two other reasons for the differences in the death rates between the countries due to cardiovascular disease

1

(2)

2

(2)

(Total 8 marks)

18

14 The diagram below shows the structure of the heart and some associated blood vessels

(a) Name the parts labelled A B and C

A

B

C (2)

19

(b) Describe how the structure of the left ventricle and the parts labelled B and C enable the left ventricle to carry out its function

(4)

(c) Many organs such as the uterus heart and kidneys of a pregnant woman use more oxygen than when she is not pregnant The graph below shows the increased usage of oxygen by these organs near the end of pregnancy as compared with the oxygen used before pregnancy

Uterus Heart Kidneys

8

7

6

5

4

3

2

1

0

Increase inoxygen used cm min3 ndash1

20

Suggest why the use of oxygen by each of the following organs increases during pregnancy

(i) Uterus

(ii) Heart

(4)

(Total 10 marks)

21

15 (a) Studies show that individuals who exercise regularly at 70 of their maximum heart rate significantly reduce their risk of cardiovascular disease Two reasons for this are that regular exercise reduces both the percentage body fat and the overall cholesterol level in blood plasma

(i) Describe the procedure for obtaining skinfold measurements to estimate percentage body fat

(4)

(ii) Explain why having high percentage body fat increases the risk of cardiovascular disease

(2)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

9

(ii) Describe one characteristic feature that you used to identify D

(1)

(Total 8 marks)

7 The following information is taken from a web site promoting a margarine

Cholesterol in the body comes from two sources A small amount is eaten in certain foods but most is actually produced by our liver and we need some in our bodies to stay healthy The liver produces cholesterol when saturated fats are eaten Todayrsquos diet contains a lot of saturated fat and therefore the liver produces more cholesterol than the body actually requires To complicate matters there are two types of cholesterol ndash HDL (good) and LDL (bad) cholesterol

Our healthier margarine is a low fat spread enriched with plant sterols Plant sterols have been clinically proven to lower cholesterol levels by reducing the cholesterol being absorbed from the gut This helps to maintain a healthy heart

Independent clinical trials prove that moving to a diet that includes 20ndash25 g of healthier margarine per day gives average LDL cholesterol reductions of 10ndash15 There is no effect on HDL cholesterol If you eat less than this amount you will still see a reduction although it will not be as high as it could be Eating more will not give a significantly greater cholesterol lowering effect

(a) Give one way in which cholesterol in our bodies ensures that we lsquostay healthyrsquo

(1)

10

(b) Explain how high levels of LDL can affect the risk of heart disease

(4)

(c) Use information from the passage to suggest

(i) one way other than eating margarine in which blood cholesterol levels could be reduced by a change of diet

(1)

(ii) a reason why eating more than 20ndash25 g of healthier margarine a day lsquowill not give a significantly greater cholesterol lowering effectrsquo

(2)

(Total 8 marks)

11

8 (a) The table below refers to structural features of two types of blood vessels If the feature is correct place a tick ( ) in the appropriate box and if the feature is incorrect place a cross ( ) in the appropriate box

Blood vessel Structural feature

Valves present Wall has pores Wall a single layer of cells

Capillary

Vein (3)

(b) The wall of the aorta a major artery has many elastic fibres in it Suggest a reason for the presence of these fibres

(1)

(Total 4 marks)

9 (a) Describe three structural differences between arteries and veins

Arteries Veins

1

2

3

(3)

12

(b) Suggest why arteries are more likely than veins to develop atherosclerosis

(1)

(c) The diagram below shows how tissue fluid is formed from blood plasma

Describe and explain how fluid is forced out of the capillaries to form tissue fluid at the arterial end of the capillary

(2)

(d) (i) Give one reason why fluid might accumulate within the tissues and cause swelling

(1)

13

(ii) Name this type of swelling in the tissues

(1)

(Total 8 marks)

10 The composition of our diet may be associated with the development of disease in a number of our body organs Explain how diet may be associated with the development of the following diseases

Coronary heart disease (CHD)

(Total 3 marks)

11 The diagrams below show a pig (a mammal) and a flatworm (a small pond animal)

times005 times5

14

(a) Explain why a pig has a heart and circulatory system whereas a flatworm does not

(2)

(b) The diagram below shows a cross-section of a mammalian heart The positions of the valves are shown by the four circles

(i) On the diagram indicate whether each valve is open or closed during ventricular systole (contraction of the ventricles) by writing lsquoopenrsquo or lsquoclosedrsquo on the lines provided Do not draw the valves

(2)

(ii) Indicate the position of the sino-atrial node (pacemaker) by drawing a cross on the diagram

(1)

(iii) State the role of the sino-atrial node

(1)

15

(c) Suggest two advantages of the coronary artery branching directly off the aorta

1

2

(2)

(Total 8 marks)

12 (a) The diagram below summarises some of the steps involved in blood clotting Complete the diagram by writing in the missing words in the boxes

Thrombin

Fibrin

Thromboplastin released by damaged cells and

(3)

(b) Describe the possible effects of a blood clot forming in a coronary artery

(3)

16

(c) Name one drug that helps to prevent clotting

(1)

(Total 7 marks)

13 The chart below shows the number of deaths from cardiovascular disease per 100 000 population for men and women in four countries

Numberof

deathsper

100 000population

1000 ndash

800 ndash

600 ndash

400 ndash

200 ndash

0 ndash ndash ndash ndashndash

France Spain Englandand Wales

Russia

Women

Men

ndash

17

(a) Describe the differences in the death rates shown in the chart above

(3)

(b) One possible reason for the differences in the death rates due to cardiovascular disease between the different countries is the quantity of fruit and vegetables eaten

Write a suitable null hypothesis that could be tested by an epidemiologist investigating the effect of fruit and vegetable consumption on deaths from cardiovascular disease

(1)

(c) Suggest and explain two other reasons for the differences in the death rates between the countries due to cardiovascular disease

1

(2)

2

(2)

(Total 8 marks)

18

14 The diagram below shows the structure of the heart and some associated blood vessels

(a) Name the parts labelled A B and C

A

B

C (2)

19

(b) Describe how the structure of the left ventricle and the parts labelled B and C enable the left ventricle to carry out its function

(4)

(c) Many organs such as the uterus heart and kidneys of a pregnant woman use more oxygen than when she is not pregnant The graph below shows the increased usage of oxygen by these organs near the end of pregnancy as compared with the oxygen used before pregnancy

Uterus Heart Kidneys

8

7

6

5

4

3

2

1

0

Increase inoxygen used cm min3 ndash1

20

Suggest why the use of oxygen by each of the following organs increases during pregnancy

(i) Uterus

(ii) Heart

(4)

(Total 10 marks)

21

15 (a) Studies show that individuals who exercise regularly at 70 of their maximum heart rate significantly reduce their risk of cardiovascular disease Two reasons for this are that regular exercise reduces both the percentage body fat and the overall cholesterol level in blood plasma

(i) Describe the procedure for obtaining skinfold measurements to estimate percentage body fat

(4)

(ii) Explain why having high percentage body fat increases the risk of cardiovascular disease

(2)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

10

(b) Explain how high levels of LDL can affect the risk of heart disease

(4)

(c) Use information from the passage to suggest

(i) one way other than eating margarine in which blood cholesterol levels could be reduced by a change of diet

(1)

(ii) a reason why eating more than 20ndash25 g of healthier margarine a day lsquowill not give a significantly greater cholesterol lowering effectrsquo

(2)

(Total 8 marks)

11

8 (a) The table below refers to structural features of two types of blood vessels If the feature is correct place a tick ( ) in the appropriate box and if the feature is incorrect place a cross ( ) in the appropriate box

Blood vessel Structural feature

Valves present Wall has pores Wall a single layer of cells

Capillary

Vein (3)

(b) The wall of the aorta a major artery has many elastic fibres in it Suggest a reason for the presence of these fibres

(1)

(Total 4 marks)

9 (a) Describe three structural differences between arteries and veins

Arteries Veins

1

2

3

(3)

12

(b) Suggest why arteries are more likely than veins to develop atherosclerosis

(1)

(c) The diagram below shows how tissue fluid is formed from blood plasma

Describe and explain how fluid is forced out of the capillaries to form tissue fluid at the arterial end of the capillary

(2)

(d) (i) Give one reason why fluid might accumulate within the tissues and cause swelling

(1)

13

(ii) Name this type of swelling in the tissues

(1)

(Total 8 marks)

10 The composition of our diet may be associated with the development of disease in a number of our body organs Explain how diet may be associated with the development of the following diseases

Coronary heart disease (CHD)

(Total 3 marks)

11 The diagrams below show a pig (a mammal) and a flatworm (a small pond animal)

times005 times5

14

(a) Explain why a pig has a heart and circulatory system whereas a flatworm does not

(2)

(b) The diagram below shows a cross-section of a mammalian heart The positions of the valves are shown by the four circles

(i) On the diagram indicate whether each valve is open or closed during ventricular systole (contraction of the ventricles) by writing lsquoopenrsquo or lsquoclosedrsquo on the lines provided Do not draw the valves

(2)

(ii) Indicate the position of the sino-atrial node (pacemaker) by drawing a cross on the diagram

(1)

(iii) State the role of the sino-atrial node

(1)

15

(c) Suggest two advantages of the coronary artery branching directly off the aorta

1

2

(2)

(Total 8 marks)

12 (a) The diagram below summarises some of the steps involved in blood clotting Complete the diagram by writing in the missing words in the boxes

Thrombin

Fibrin

Thromboplastin released by damaged cells and

(3)

(b) Describe the possible effects of a blood clot forming in a coronary artery

(3)

16

(c) Name one drug that helps to prevent clotting

(1)

(Total 7 marks)

13 The chart below shows the number of deaths from cardiovascular disease per 100 000 population for men and women in four countries

Numberof

deathsper

100 000population

1000 ndash

800 ndash

600 ndash

400 ndash

200 ndash

0 ndash ndash ndash ndashndash

France Spain Englandand Wales

Russia

Women

Men

ndash

17

(a) Describe the differences in the death rates shown in the chart above

(3)

(b) One possible reason for the differences in the death rates due to cardiovascular disease between the different countries is the quantity of fruit and vegetables eaten

Write a suitable null hypothesis that could be tested by an epidemiologist investigating the effect of fruit and vegetable consumption on deaths from cardiovascular disease

(1)

(c) Suggest and explain two other reasons for the differences in the death rates between the countries due to cardiovascular disease

1

(2)

2

(2)

(Total 8 marks)

18

14 The diagram below shows the structure of the heart and some associated blood vessels

(a) Name the parts labelled A B and C

A

B

C (2)

19

(b) Describe how the structure of the left ventricle and the parts labelled B and C enable the left ventricle to carry out its function

(4)

(c) Many organs such as the uterus heart and kidneys of a pregnant woman use more oxygen than when she is not pregnant The graph below shows the increased usage of oxygen by these organs near the end of pregnancy as compared with the oxygen used before pregnancy

Uterus Heart Kidneys

8

7

6

5

4

3

2

1

0

Increase inoxygen used cm min3 ndash1

20

Suggest why the use of oxygen by each of the following organs increases during pregnancy

(i) Uterus

(ii) Heart

(4)

(Total 10 marks)

21

15 (a) Studies show that individuals who exercise regularly at 70 of their maximum heart rate significantly reduce their risk of cardiovascular disease Two reasons for this are that regular exercise reduces both the percentage body fat and the overall cholesterol level in blood plasma

(i) Describe the procedure for obtaining skinfold measurements to estimate percentage body fat

(4)

(ii) Explain why having high percentage body fat increases the risk of cardiovascular disease

(2)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

11

8 (a) The table below refers to structural features of two types of blood vessels If the feature is correct place a tick ( ) in the appropriate box and if the feature is incorrect place a cross ( ) in the appropriate box

Blood vessel Structural feature

Valves present Wall has pores Wall a single layer of cells

Capillary

Vein (3)

(b) The wall of the aorta a major artery has many elastic fibres in it Suggest a reason for the presence of these fibres

(1)

(Total 4 marks)

9 (a) Describe three structural differences between arteries and veins

Arteries Veins

1

2

3

(3)

12

(b) Suggest why arteries are more likely than veins to develop atherosclerosis

(1)

(c) The diagram below shows how tissue fluid is formed from blood plasma

Describe and explain how fluid is forced out of the capillaries to form tissue fluid at the arterial end of the capillary

(2)

(d) (i) Give one reason why fluid might accumulate within the tissues and cause swelling

(1)

13

(ii) Name this type of swelling in the tissues

(1)

(Total 8 marks)

10 The composition of our diet may be associated with the development of disease in a number of our body organs Explain how diet may be associated with the development of the following diseases

Coronary heart disease (CHD)

(Total 3 marks)

11 The diagrams below show a pig (a mammal) and a flatworm (a small pond animal)

times005 times5

14

(a) Explain why a pig has a heart and circulatory system whereas a flatworm does not

(2)

(b) The diagram below shows a cross-section of a mammalian heart The positions of the valves are shown by the four circles

(i) On the diagram indicate whether each valve is open or closed during ventricular systole (contraction of the ventricles) by writing lsquoopenrsquo or lsquoclosedrsquo on the lines provided Do not draw the valves

(2)

(ii) Indicate the position of the sino-atrial node (pacemaker) by drawing a cross on the diagram

(1)

(iii) State the role of the sino-atrial node

(1)

15

(c) Suggest two advantages of the coronary artery branching directly off the aorta

1

2

(2)

(Total 8 marks)

12 (a) The diagram below summarises some of the steps involved in blood clotting Complete the diagram by writing in the missing words in the boxes

Thrombin

Fibrin

Thromboplastin released by damaged cells and

(3)

(b) Describe the possible effects of a blood clot forming in a coronary artery

(3)

16

(c) Name one drug that helps to prevent clotting

(1)

(Total 7 marks)

13 The chart below shows the number of deaths from cardiovascular disease per 100 000 population for men and women in four countries

Numberof

deathsper

100 000population

1000 ndash

800 ndash

600 ndash

400 ndash

200 ndash

0 ndash ndash ndash ndashndash

France Spain Englandand Wales

Russia

Women

Men

ndash

17

(a) Describe the differences in the death rates shown in the chart above

(3)

(b) One possible reason for the differences in the death rates due to cardiovascular disease between the different countries is the quantity of fruit and vegetables eaten

Write a suitable null hypothesis that could be tested by an epidemiologist investigating the effect of fruit and vegetable consumption on deaths from cardiovascular disease

(1)

(c) Suggest and explain two other reasons for the differences in the death rates between the countries due to cardiovascular disease

1

(2)

2

(2)

(Total 8 marks)

18

14 The diagram below shows the structure of the heart and some associated blood vessels

(a) Name the parts labelled A B and C

A

B

C (2)

19

(b) Describe how the structure of the left ventricle and the parts labelled B and C enable the left ventricle to carry out its function

(4)

(c) Many organs such as the uterus heart and kidneys of a pregnant woman use more oxygen than when she is not pregnant The graph below shows the increased usage of oxygen by these organs near the end of pregnancy as compared with the oxygen used before pregnancy

Uterus Heart Kidneys

8

7

6

5

4

3

2

1

0

Increase inoxygen used cm min3 ndash1

20

Suggest why the use of oxygen by each of the following organs increases during pregnancy

(i) Uterus

(ii) Heart

(4)

(Total 10 marks)

21

15 (a) Studies show that individuals who exercise regularly at 70 of their maximum heart rate significantly reduce their risk of cardiovascular disease Two reasons for this are that regular exercise reduces both the percentage body fat and the overall cholesterol level in blood plasma

(i) Describe the procedure for obtaining skinfold measurements to estimate percentage body fat

(4)

(ii) Explain why having high percentage body fat increases the risk of cardiovascular disease

(2)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

12

(b) Suggest why arteries are more likely than veins to develop atherosclerosis

(1)

(c) The diagram below shows how tissue fluid is formed from blood plasma

Describe and explain how fluid is forced out of the capillaries to form tissue fluid at the arterial end of the capillary

(2)

(d) (i) Give one reason why fluid might accumulate within the tissues and cause swelling

(1)

13

(ii) Name this type of swelling in the tissues

(1)

(Total 8 marks)

10 The composition of our diet may be associated with the development of disease in a number of our body organs Explain how diet may be associated with the development of the following diseases

Coronary heart disease (CHD)

(Total 3 marks)

11 The diagrams below show a pig (a mammal) and a flatworm (a small pond animal)

times005 times5

14

(a) Explain why a pig has a heart and circulatory system whereas a flatworm does not

(2)

(b) The diagram below shows a cross-section of a mammalian heart The positions of the valves are shown by the four circles

(i) On the diagram indicate whether each valve is open or closed during ventricular systole (contraction of the ventricles) by writing lsquoopenrsquo or lsquoclosedrsquo on the lines provided Do not draw the valves

(2)

(ii) Indicate the position of the sino-atrial node (pacemaker) by drawing a cross on the diagram

(1)

(iii) State the role of the sino-atrial node

(1)

15

(c) Suggest two advantages of the coronary artery branching directly off the aorta

1

2

(2)

(Total 8 marks)

12 (a) The diagram below summarises some of the steps involved in blood clotting Complete the diagram by writing in the missing words in the boxes

Thrombin

Fibrin

Thromboplastin released by damaged cells and

(3)

(b) Describe the possible effects of a blood clot forming in a coronary artery

(3)

16

(c) Name one drug that helps to prevent clotting

(1)

(Total 7 marks)

13 The chart below shows the number of deaths from cardiovascular disease per 100 000 population for men and women in four countries

Numberof

deathsper

100 000population

1000 ndash

800 ndash

600 ndash

400 ndash

200 ndash

0 ndash ndash ndash ndashndash

France Spain Englandand Wales

Russia

Women

Men

ndash

17

(a) Describe the differences in the death rates shown in the chart above

(3)

(b) One possible reason for the differences in the death rates due to cardiovascular disease between the different countries is the quantity of fruit and vegetables eaten

Write a suitable null hypothesis that could be tested by an epidemiologist investigating the effect of fruit and vegetable consumption on deaths from cardiovascular disease

(1)

(c) Suggest and explain two other reasons for the differences in the death rates between the countries due to cardiovascular disease

1

(2)

2

(2)

(Total 8 marks)

18

14 The diagram below shows the structure of the heart and some associated blood vessels

(a) Name the parts labelled A B and C

A

B

C (2)

19

(b) Describe how the structure of the left ventricle and the parts labelled B and C enable the left ventricle to carry out its function

(4)

(c) Many organs such as the uterus heart and kidneys of a pregnant woman use more oxygen than when she is not pregnant The graph below shows the increased usage of oxygen by these organs near the end of pregnancy as compared with the oxygen used before pregnancy

Uterus Heart Kidneys

8

7

6

5

4

3

2

1

0

Increase inoxygen used cm min3 ndash1

20

Suggest why the use of oxygen by each of the following organs increases during pregnancy

(i) Uterus

(ii) Heart

(4)

(Total 10 marks)

21

15 (a) Studies show that individuals who exercise regularly at 70 of their maximum heart rate significantly reduce their risk of cardiovascular disease Two reasons for this are that regular exercise reduces both the percentage body fat and the overall cholesterol level in blood plasma

(i) Describe the procedure for obtaining skinfold measurements to estimate percentage body fat

(4)

(ii) Explain why having high percentage body fat increases the risk of cardiovascular disease

(2)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

13

(ii) Name this type of swelling in the tissues

(1)

(Total 8 marks)

10 The composition of our diet may be associated with the development of disease in a number of our body organs Explain how diet may be associated with the development of the following diseases

Coronary heart disease (CHD)

(Total 3 marks)

11 The diagrams below show a pig (a mammal) and a flatworm (a small pond animal)

times005 times5

14

(a) Explain why a pig has a heart and circulatory system whereas a flatworm does not

(2)

(b) The diagram below shows a cross-section of a mammalian heart The positions of the valves are shown by the four circles

(i) On the diagram indicate whether each valve is open or closed during ventricular systole (contraction of the ventricles) by writing lsquoopenrsquo or lsquoclosedrsquo on the lines provided Do not draw the valves

(2)

(ii) Indicate the position of the sino-atrial node (pacemaker) by drawing a cross on the diagram

(1)

(iii) State the role of the sino-atrial node

(1)

15

(c) Suggest two advantages of the coronary artery branching directly off the aorta

1

2

(2)

(Total 8 marks)

12 (a) The diagram below summarises some of the steps involved in blood clotting Complete the diagram by writing in the missing words in the boxes

Thrombin

Fibrin

Thromboplastin released by damaged cells and

(3)

(b) Describe the possible effects of a blood clot forming in a coronary artery

(3)

16

(c) Name one drug that helps to prevent clotting

(1)

(Total 7 marks)

13 The chart below shows the number of deaths from cardiovascular disease per 100 000 population for men and women in four countries

Numberof

deathsper

100 000population

1000 ndash

800 ndash

600 ndash

400 ndash

200 ndash

0 ndash ndash ndash ndashndash

France Spain Englandand Wales

Russia

Women

Men

ndash

17

(a) Describe the differences in the death rates shown in the chart above

(3)

(b) One possible reason for the differences in the death rates due to cardiovascular disease between the different countries is the quantity of fruit and vegetables eaten

Write a suitable null hypothesis that could be tested by an epidemiologist investigating the effect of fruit and vegetable consumption on deaths from cardiovascular disease

(1)

(c) Suggest and explain two other reasons for the differences in the death rates between the countries due to cardiovascular disease

1

(2)

2

(2)

(Total 8 marks)

18

14 The diagram below shows the structure of the heart and some associated blood vessels

(a) Name the parts labelled A B and C

A

B

C (2)

19

(b) Describe how the structure of the left ventricle and the parts labelled B and C enable the left ventricle to carry out its function

(4)

(c) Many organs such as the uterus heart and kidneys of a pregnant woman use more oxygen than when she is not pregnant The graph below shows the increased usage of oxygen by these organs near the end of pregnancy as compared with the oxygen used before pregnancy

Uterus Heart Kidneys

8

7

6

5

4

3

2

1

0

Increase inoxygen used cm min3 ndash1

20

Suggest why the use of oxygen by each of the following organs increases during pregnancy

(i) Uterus

(ii) Heart

(4)

(Total 10 marks)

21

15 (a) Studies show that individuals who exercise regularly at 70 of their maximum heart rate significantly reduce their risk of cardiovascular disease Two reasons for this are that regular exercise reduces both the percentage body fat and the overall cholesterol level in blood plasma

(i) Describe the procedure for obtaining skinfold measurements to estimate percentage body fat

(4)

(ii) Explain why having high percentage body fat increases the risk of cardiovascular disease

(2)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

14

(a) Explain why a pig has a heart and circulatory system whereas a flatworm does not

(2)

(b) The diagram below shows a cross-section of a mammalian heart The positions of the valves are shown by the four circles

(i) On the diagram indicate whether each valve is open or closed during ventricular systole (contraction of the ventricles) by writing lsquoopenrsquo or lsquoclosedrsquo on the lines provided Do not draw the valves

(2)

(ii) Indicate the position of the sino-atrial node (pacemaker) by drawing a cross on the diagram

(1)

(iii) State the role of the sino-atrial node

(1)

15

(c) Suggest two advantages of the coronary artery branching directly off the aorta

1

2

(2)

(Total 8 marks)

12 (a) The diagram below summarises some of the steps involved in blood clotting Complete the diagram by writing in the missing words in the boxes

Thrombin

Fibrin

Thromboplastin released by damaged cells and

(3)

(b) Describe the possible effects of a blood clot forming in a coronary artery

(3)

16

(c) Name one drug that helps to prevent clotting

(1)

(Total 7 marks)

13 The chart below shows the number of deaths from cardiovascular disease per 100 000 population for men and women in four countries

Numberof

deathsper

100 000population

1000 ndash

800 ndash

600 ndash

400 ndash

200 ndash

0 ndash ndash ndash ndashndash

France Spain Englandand Wales

Russia

Women

Men

ndash

17

(a) Describe the differences in the death rates shown in the chart above

(3)

(b) One possible reason for the differences in the death rates due to cardiovascular disease between the different countries is the quantity of fruit and vegetables eaten

Write a suitable null hypothesis that could be tested by an epidemiologist investigating the effect of fruit and vegetable consumption on deaths from cardiovascular disease

(1)

(c) Suggest and explain two other reasons for the differences in the death rates between the countries due to cardiovascular disease

1

(2)

2

(2)

(Total 8 marks)

18

14 The diagram below shows the structure of the heart and some associated blood vessels

(a) Name the parts labelled A B and C

A

B

C (2)

19

(b) Describe how the structure of the left ventricle and the parts labelled B and C enable the left ventricle to carry out its function

(4)

(c) Many organs such as the uterus heart and kidneys of a pregnant woman use more oxygen than when she is not pregnant The graph below shows the increased usage of oxygen by these organs near the end of pregnancy as compared with the oxygen used before pregnancy

Uterus Heart Kidneys

8

7

6

5

4

3

2

1

0

Increase inoxygen used cm min3 ndash1

20

Suggest why the use of oxygen by each of the following organs increases during pregnancy

(i) Uterus

(ii) Heart

(4)

(Total 10 marks)

21

15 (a) Studies show that individuals who exercise regularly at 70 of their maximum heart rate significantly reduce their risk of cardiovascular disease Two reasons for this are that regular exercise reduces both the percentage body fat and the overall cholesterol level in blood plasma

(i) Describe the procedure for obtaining skinfold measurements to estimate percentage body fat

(4)

(ii) Explain why having high percentage body fat increases the risk of cardiovascular disease

(2)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

15

(c) Suggest two advantages of the coronary artery branching directly off the aorta

1

2

(2)

(Total 8 marks)

12 (a) The diagram below summarises some of the steps involved in blood clotting Complete the diagram by writing in the missing words in the boxes

Thrombin

Fibrin

Thromboplastin released by damaged cells and

(3)

(b) Describe the possible effects of a blood clot forming in a coronary artery

(3)

16

(c) Name one drug that helps to prevent clotting

(1)

(Total 7 marks)

13 The chart below shows the number of deaths from cardiovascular disease per 100 000 population for men and women in four countries

Numberof

deathsper

100 000population

1000 ndash

800 ndash

600 ndash

400 ndash

200 ndash

0 ndash ndash ndash ndashndash

France Spain Englandand Wales

Russia

Women

Men

ndash

17

(a) Describe the differences in the death rates shown in the chart above

(3)

(b) One possible reason for the differences in the death rates due to cardiovascular disease between the different countries is the quantity of fruit and vegetables eaten

Write a suitable null hypothesis that could be tested by an epidemiologist investigating the effect of fruit and vegetable consumption on deaths from cardiovascular disease

(1)

(c) Suggest and explain two other reasons for the differences in the death rates between the countries due to cardiovascular disease

1

(2)

2

(2)

(Total 8 marks)

18

14 The diagram below shows the structure of the heart and some associated blood vessels

(a) Name the parts labelled A B and C

A

B

C (2)

19

(b) Describe how the structure of the left ventricle and the parts labelled B and C enable the left ventricle to carry out its function

(4)

(c) Many organs such as the uterus heart and kidneys of a pregnant woman use more oxygen than when she is not pregnant The graph below shows the increased usage of oxygen by these organs near the end of pregnancy as compared with the oxygen used before pregnancy

Uterus Heart Kidneys

8

7

6

5

4

3

2

1

0

Increase inoxygen used cm min3 ndash1

20

Suggest why the use of oxygen by each of the following organs increases during pregnancy

(i) Uterus

(ii) Heart

(4)

(Total 10 marks)

21

15 (a) Studies show that individuals who exercise regularly at 70 of their maximum heart rate significantly reduce their risk of cardiovascular disease Two reasons for this are that regular exercise reduces both the percentage body fat and the overall cholesterol level in blood plasma

(i) Describe the procedure for obtaining skinfold measurements to estimate percentage body fat

(4)

(ii) Explain why having high percentage body fat increases the risk of cardiovascular disease

(2)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

16

(c) Name one drug that helps to prevent clotting

(1)

(Total 7 marks)

13 The chart below shows the number of deaths from cardiovascular disease per 100 000 population for men and women in four countries

Numberof

deathsper

100 000population

1000 ndash

800 ndash

600 ndash

400 ndash

200 ndash

0 ndash ndash ndash ndashndash

France Spain Englandand Wales

Russia

Women

Men

ndash

17

(a) Describe the differences in the death rates shown in the chart above

(3)

(b) One possible reason for the differences in the death rates due to cardiovascular disease between the different countries is the quantity of fruit and vegetables eaten

Write a suitable null hypothesis that could be tested by an epidemiologist investigating the effect of fruit and vegetable consumption on deaths from cardiovascular disease

(1)

(c) Suggest and explain two other reasons for the differences in the death rates between the countries due to cardiovascular disease

1

(2)

2

(2)

(Total 8 marks)

18

14 The diagram below shows the structure of the heart and some associated blood vessels

(a) Name the parts labelled A B and C

A

B

C (2)

19

(b) Describe how the structure of the left ventricle and the parts labelled B and C enable the left ventricle to carry out its function

(4)

(c) Many organs such as the uterus heart and kidneys of a pregnant woman use more oxygen than when she is not pregnant The graph below shows the increased usage of oxygen by these organs near the end of pregnancy as compared with the oxygen used before pregnancy

Uterus Heart Kidneys

8

7

6

5

4

3

2

1

0

Increase inoxygen used cm min3 ndash1

20

Suggest why the use of oxygen by each of the following organs increases during pregnancy

(i) Uterus

(ii) Heart

(4)

(Total 10 marks)

21

15 (a) Studies show that individuals who exercise regularly at 70 of their maximum heart rate significantly reduce their risk of cardiovascular disease Two reasons for this are that regular exercise reduces both the percentage body fat and the overall cholesterol level in blood plasma

(i) Describe the procedure for obtaining skinfold measurements to estimate percentage body fat

(4)

(ii) Explain why having high percentage body fat increases the risk of cardiovascular disease

(2)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

17

(a) Describe the differences in the death rates shown in the chart above

(3)

(b) One possible reason for the differences in the death rates due to cardiovascular disease between the different countries is the quantity of fruit and vegetables eaten

Write a suitable null hypothesis that could be tested by an epidemiologist investigating the effect of fruit and vegetable consumption on deaths from cardiovascular disease

(1)

(c) Suggest and explain two other reasons for the differences in the death rates between the countries due to cardiovascular disease

1

(2)

2

(2)

(Total 8 marks)

18

14 The diagram below shows the structure of the heart and some associated blood vessels

(a) Name the parts labelled A B and C

A

B

C (2)

19

(b) Describe how the structure of the left ventricle and the parts labelled B and C enable the left ventricle to carry out its function

(4)

(c) Many organs such as the uterus heart and kidneys of a pregnant woman use more oxygen than when she is not pregnant The graph below shows the increased usage of oxygen by these organs near the end of pregnancy as compared with the oxygen used before pregnancy

Uterus Heart Kidneys

8

7

6

5

4

3

2

1

0

Increase inoxygen used cm min3 ndash1

20

Suggest why the use of oxygen by each of the following organs increases during pregnancy

(i) Uterus

(ii) Heart

(4)

(Total 10 marks)

21

15 (a) Studies show that individuals who exercise regularly at 70 of their maximum heart rate significantly reduce their risk of cardiovascular disease Two reasons for this are that regular exercise reduces both the percentage body fat and the overall cholesterol level in blood plasma

(i) Describe the procedure for obtaining skinfold measurements to estimate percentage body fat

(4)

(ii) Explain why having high percentage body fat increases the risk of cardiovascular disease

(2)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

18

14 The diagram below shows the structure of the heart and some associated blood vessels

(a) Name the parts labelled A B and C

A

B

C (2)

19

(b) Describe how the structure of the left ventricle and the parts labelled B and C enable the left ventricle to carry out its function

(4)

(c) Many organs such as the uterus heart and kidneys of a pregnant woman use more oxygen than when she is not pregnant The graph below shows the increased usage of oxygen by these organs near the end of pregnancy as compared with the oxygen used before pregnancy

Uterus Heart Kidneys

8

7

6

5

4

3

2

1

0

Increase inoxygen used cm min3 ndash1

20

Suggest why the use of oxygen by each of the following organs increases during pregnancy

(i) Uterus

(ii) Heart

(4)

(Total 10 marks)

21

15 (a) Studies show that individuals who exercise regularly at 70 of their maximum heart rate significantly reduce their risk of cardiovascular disease Two reasons for this are that regular exercise reduces both the percentage body fat and the overall cholesterol level in blood plasma

(i) Describe the procedure for obtaining skinfold measurements to estimate percentage body fat

(4)

(ii) Explain why having high percentage body fat increases the risk of cardiovascular disease

(2)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

19

(b) Describe how the structure of the left ventricle and the parts labelled B and C enable the left ventricle to carry out its function

(4)

(c) Many organs such as the uterus heart and kidneys of a pregnant woman use more oxygen than when she is not pregnant The graph below shows the increased usage of oxygen by these organs near the end of pregnancy as compared with the oxygen used before pregnancy

Uterus Heart Kidneys

8

7

6

5

4

3

2

1

0

Increase inoxygen used cm min3 ndash1

20

Suggest why the use of oxygen by each of the following organs increases during pregnancy

(i) Uterus

(ii) Heart

(4)

(Total 10 marks)

21

15 (a) Studies show that individuals who exercise regularly at 70 of their maximum heart rate significantly reduce their risk of cardiovascular disease Two reasons for this are that regular exercise reduces both the percentage body fat and the overall cholesterol level in blood plasma

(i) Describe the procedure for obtaining skinfold measurements to estimate percentage body fat

(4)

(ii) Explain why having high percentage body fat increases the risk of cardiovascular disease

(2)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

20

Suggest why the use of oxygen by each of the following organs increases during pregnancy

(i) Uterus

(ii) Heart

(4)

(Total 10 marks)

21

15 (a) Studies show that individuals who exercise regularly at 70 of their maximum heart rate significantly reduce their risk of cardiovascular disease Two reasons for this are that regular exercise reduces both the percentage body fat and the overall cholesterol level in blood plasma

(i) Describe the procedure for obtaining skinfold measurements to estimate percentage body fat

(4)

(ii) Explain why having high percentage body fat increases the risk of cardiovascular disease

(2)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

21

15 (a) Studies show that individuals who exercise regularly at 70 of their maximum heart rate significantly reduce their risk of cardiovascular disease Two reasons for this are that regular exercise reduces both the percentage body fat and the overall cholesterol level in blood plasma

(i) Describe the procedure for obtaining skinfold measurements to estimate percentage body fat

(4)

(ii) Explain why having high percentage body fat increases the risk of cardiovascular disease

(2)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

22

(b) Cholesterol is transported around the body in the blood by either high density lipoproteins (HDL) or low density lipoproteins (LDL)

The graph below shows the relationship between LDL cholesterol and coronary heart disease

7

6

5

4

3

2

1

0

Prevalence ofcoronary heartdisease ()

lt 120 120ndash141 142ndash167 gt 167LDL cholesterol mg dmndash3

Describe the relationship between LDL cholesterol and coronary heart disease

(2)

(Total 8 marks)

16 Carbohydrates and lipids are both sources of energy in the diet A high carbohydrate intake stimulates the production of fatty acids Eating excessive amounts of carbohydrates can lead to obesity

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

23

(a) (i) The diagram below illustrates part of the structure of a fatty acid with the formula C15H31COOH Complete the diagram of the molecule

HmdashCmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

Cmdash

H

H

(2)

(ii) State whether this fatty acid is saturated or unsaturated Give a reason for your answer

(2)

(b) (i) Explain what is meant by the term risk factor

(1)

(ii) Explain how obesity increases the risk of developing coronary heart disease

(3)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

24

(c) Energy drinks containing glucose provide a concentrated source of energy that is particularly valuable during exercise

Explain why glucose can provide a quick energy boost during exercise

(3)

(Total 11 marks)

17 The diagram below represents the sequence of stages during one complete cardiac cycle

(a) Name Stage B

(1)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

25

(b) Describe what is happening in the heart during complete cardiac diastole

(2)

(c) Describe how cardiac muscle is supplied with oxygen

(3)

(Total 6 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

26

18 It is suggested that the amount of dietary fibre has an influence on the occurrence of cancer of the colon and diverticular disease

The graph below shows the number of deaths (mortality) from cancer of the colon plotted against the mass of dietary fibre

100

90

8020 22 24 26

Dietary fibre g day ndash1

Deaths fromcolon cancerper 100 000 ofthe population

(a) (i) Describe the relationship between dietary fibre and mortality from cancer of the colon

(3)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

27

(ii) Explain why increasing the intake of dietary fibre may affect the incidence of cancer of the colon

(2)

(b) Diverticular disease has been observed to be particularly associated with people over 70 years old Suggest reasons for this observation

(3)

(Total 8 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

28

19 Several risk factors influence the onset of coronary heart disease (CHD) including high blood cholesterol level high blood pressure and smoking

The chart shows the effect of combining these three factors on the incidence of CHD

700

600

500

400

300

200

100

0

Incidenceof CHDper100 000people

0 1 2 3Number of risk factors

(a) Describe the effect on the incidence of CHD of increasing the number of risk factors

(3)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

29

(b) Explain how each of these risk factors can influence the onset of CHD

High blood cholesterol

High blood pressure

Smoking

(6)

(Total 9 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

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helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

30

20 The diagram below shows a transverse section of a blood vessel as seen using low magnification of a light microscope

A

(a) Name the type of blood vessel shown in the diagram

(1)

(b) The layer labelled A contains smooth muscle fibres collagen and elastic fibres

(i) Name layer A

(1)

(ii) Describe the function of the collagen fibres

(2)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

31

(c) The diagrams below show the single blood circulatory system of a fish and the double circulatory system of a mammal

Gills

Lungs

Tissues

HeartTissues

Heart

Fish

Mammal

KEY

Deoxygenated blood

Oxygenated blood

Suggest why a double circulatory system is an advantage to a mammal

(2)

(Total 6 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

32

21 The table below shows population statistics and deaths from coronary heart disease (CHD) for males and females in England during a two year period

Number in the population Number dying from CHD

Males 23 922 144 33 879

Females 25 216 687 9 016

(a) (i) For this two year period calculate the percentage risk of a male dying from CHD Show your working

(1)

(ii) Use the data in the table above to calculate how many times females are less likely to die from CHD than males

(1)

(b) Body Mass Index (BMI) can be used to indicate whether a person is overweight The chart below shows the effect of having a high BMI on the risk of dying of CHD when compared with a control group with a normal BMI of 20 A person with a BMI of 30 is obese

50

40

30

20

10

020 25 30 35

Increase inrisk of death

due to CHD

Body Mass Index (BMI)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

33

(i) Describe the trend shown in the chart

(2)

(ii) Give the formula used to calculate BMI

(1)

(iii) Explain why people who are overweight are more likely to die from CHD

(3)

(Total 8 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

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helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

34

22 Daphnia (water fleas) can be used to determine the effect of chemicals on heart rate

(a) (i) Explain one reason why Daphnia is a suitable organism for this experiment

(1)

(ii) An experiment was carried out to investigate the effect of caffeine on the heart rate of Daphnia State two variables that you would need to control to produce reliable results

1

2

(2)

(iii) Suggest why Daphnia needs a heart and circulatory system

(2)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

35

(b) Caffeine increases human heart rate Suggest and explain why high caffeine consumption could increase a personrsquos risk of developing cardiovascular disease

(2)

(Total 7 marks)

23 Complete the paragraph below which summarises the blood clotting process

are cell fragments that stick to a site of damaged tissue

is released from this area which results in a plasma

protein called being converted to thrombin Thrombin

acts as an enzyme and catalyses the conversion of the soluble plasma

protein into long insoluble strands of the

protein These strands form a mesh that

traps to form a blood clot (Total 3 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

36

24 The diagrams below show the left side of the heart at two stages of the cardiac cycle

Diagram A Diagram B

X

(a) (i) Name structure X shown on the diagram

X (1)

(ii) Name the part of the cardiac cycle illustrated by diagram B

(1)

(iii) With reference to structures shown on diagram B describe and explain what happens during this phase of the cardiac cycle

(3)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

37

(b) Balloon angioplasty is regularly used to unblock coronary arteries that have been affected by atherosclerosis The procedure is shown in the diagram below

Guiding catheter

Unblocked coronary artery

Narrowed coronary artery

Balloon catheter withuninflated balloon

Balloon catheter withinflated balloon

Balloon catheter withpartially inflated balloon

(i) Suggest why the patient may experience chest pain as a result of this partial blocking of one of the coronary arteries

(3)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

38

(ii) Suggest why the walls of the artery return to their original position once the balloon is removed

(1)

(c) Explain why doctors may advise a patient to try a balloon angioplasty in preference to an operation such as a coronary bypass

(2)

(d) Suggest why atherosclerosis usually affects coronary arteries but not coronary veins

(1)

(Total 12 marks)

25 Diseases of the cardiovascular system are a major cause of death worldwide Most cardiovascular diseases are caused by fatty deposits called plaques The diagrams below show stages in the development of a plaque and the narrowing of the lumen of an artery

Normal lumen

Normal artery Tear in arterywall

Plaque

Narrow lumen

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

39

(a) Describe how this narrowing of the lumen can increase the risk of further damage to an artery

(2)

(b) (i) Describe the sequence of events that results in the formation of a blood clot

(3)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

40

(ii) Explain how a blood clot can cause a heart attack

(3)

(Total 8 marks)

26 Lowering the level of blood cholesterol in an individual by 1 can decrease the risk of coronary heart disease by 2ndash3 A low cholesterol diet can help to lower the level of blood cholesterol

(a) (i) Suggest a specific change in diet that could help to lower the level of blood cholesterol

(1)

(ii) Suggest and explain why a low cholesterol diet might not result in a lower blood cholesterol level

(2)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

41

(b) Statins are drugs currently in use to help lower blood cholesterol levels The table below gives the results of some trials carried out to determine if statins reduce the risk of heart disease in men and women

Drug used Number of subjects involved

of subjects who had heart attacks

reduction in heart

Control group Statin group Control group Statin group attacks

Statin A 4502 4512 159 123 226

Statin B 2223 2221 150 87 420

Statin C 3301 3304 148 89

(i) Use the figures shown in the table to calculate the reduction in heart attacks after taking Statin C Show your working

Answer (2)

(ii) State which statin was the most effective

(1)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

42

(iii) Suggest a reason for

The number of subjects involved

The control group

(2)

(Total 8 marks)

27 Sunil has angina and has been recommended to control his diet to reduce his chance of a heart attack

(a) Explain how atherosclerosis could cause the chest pain associated with an attack of angina

(3)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

43

The table below shows some of the relevant dietary information for assessing the content of three alternative breakfasts that Sunil normally eats

Meal Food Energy kJ

Carbohy- drate g

Saturated fatty acids g

Unsaturated fatty acids g

Cholesterol mg

2 slices of whole

wheat toast

580 26 05 15 0

A margarine 180 01 1 38 0

baked beans 1113 52 025 05 0

Total 781 175 58 0

2 slices of white

toast

662 29 03 17 0

B margarine 180 01 1 38 0

2 fried eggs 772 08 4 8 210

Total 299 53 135 210

2 slices of white

toast

662 29 03 17 0

C margarine 180 01 1 38 0

2 slices of cheddar cheese

948 08 6 58 58

Total 299 73 113 58

(b) (i) Complete the table by calculating the total energy of each meal (1)

(ii) Give the letter of the meal that contains the highest energy content

Meal with highest energy content (1)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

44

(iii) Suggest which meal you would recommend to Sunil if he wishes to reduce his risk of coronary heart disease Explain the reasons for your choice

(3)

(Total 8 marks)

28 The figure below shows a simplified diagram of the heart

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

45

(i) Draw arrows on the diagram to show the direction of blood flow through both sides of the heart during diastole

(1)

(ii) Name the part of the heart responsible for the initiation of the cardiac cycle

(1)

(Total 2 marks)

29 (a) The photograph below shows Daphnia (a water flea) It is a small animal that lives in freshwater

M I WalkerScience Photo Library

Daphnia has a heart which pumps fluid around its body This fluid has a higher solute concentration than the freshwater that Daphnia lives in

The table below gives four statements concerning transport in Daphnia If a statement is correct place a tick ( ) in the box to the right of that statement and if a statement is incorrect place a cross ( ) in the box

Statements about transport in Daphnia Tick or cross

(i) The movement of fluid through the heart is an example of mass transport

(ii) Daphniauses diffusion to transport oxygen into muscle cells

(iii) Daphniatends to lose water to the freshwater by osmosis

(iv) Daphniacan use active transport to move ions from the freshwater into its body

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

46

(b) A student investigated the effect of caffeine on the heart rate of Daphnia Three different Daphnia were used A B and C The table below shows her results at the end of the investigation

Daphnia Caffeine

concentration arbitrary units

Duration of observation

seconds

Number of heart beats

counted

A 5 10 50

A 5 10 53

A 5 10 47

B 10 10 73

B 10 10 76

B 10 10 76

C 15 10 101

C 15 10 99

C 15 10 100

(i) Calculate the mean number of heart beats per 10 seconds for each Daphnia

Daphnia A heart beats per 10 seconds

Daphnia B heart beats per 10 seconds

Daphnia C heart beats per 10 seconds (1)

(ii) Use your answers from (i) above to predict the mean number of heart beats in 10 seconds for another Daphnia placed in a caffeine concentration of 35 arbitrary units

(1)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

47

(iii) Suggest three reasons why the prediction you made for (ii) above may not be very reliable

1

2

2

(3)

(Total 9 marks)

30 (a) The diagram below shows a ventral (front) external view of a mammalian heart

X

Y

Z

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

48

(i) Name the structures labelled X Y and Z

X

Y

Z (3)

(ii) There are four boxes on the heart diagram Place a tick (992256) in the box that correctly identifies the position where electrical activity of the heart is initiated

(1)

(iii) Name the structure that initiates electrical activity in the heart

(1)

(b) Blood pressure within the heart varies throughout the cardiac cycle

(i) Explain what is meant by the term cardiac cycle

(2)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

49

(ii) The table below shows the range of blood pressures found in the left ventricle and in the right ventricle during one complete cardiac cycle

Ventricle Blood pressure kPa

Right 00 to 33

Left 00 to 158

Explain why the maximum blood pressure is higher in the left ventricle than in the right ventricle

(2)

(iii) Explain why blood pressure varies in a ventricle during the cardiac cycle

(2)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

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helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

50

(c) Apart from high blood pressure state two other risk factors for heart disease

(1)

(Total 12 marks)

31 Tissue fluid is formed as a result of the blood pressure forcing water and dissolved solutes such as glucose and mineral ions out of capillaries

(a) Explain how the structure of a capillary is related to the formation of tissue fluid

(3)

(b) Suggest why proteins are present in the plasma but are not normally present in tissue fluid

(2)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

51

(c) Tissue fluid is reabsorbed back into capillaries as a result of the osmotic effect of the plasma proteins Suggest why this reabsorption is reduced in a person on a protein-deficient diet

(2)

(Total 7 marks)

32 The photograph below shows two blood vessels as seen using a light microscope

Magnification times50

(a) (i) Identify the type of blood vessel labelled A on the photograph

(1)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

52

(ii) Describe two features of blood vessel A and explain the function of each feature

(4)

(b) People suffering from high blood pressure may be given Angiotensin Converting Enzyme (ACE) inhibitors The ACE inhibitor stops the conversion of an inactive substance in the blood called angiotensin I to the active form angiotensin II Angiotensin II causes blood vessels to constrict

Suggest how the ACE inhibitor could prevent the conversion of angiotensin I to angiotensin II

(4)

(Total 9 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

53

33 The photograph (below left) shows sections of two blood vessels labelled A and B The diagram (below right) shows a human heart with two of the blood vessels numbered 1 and 2

CNRIScience photo library

(a) Two of these vessels are arteries and two are veins Place a tick in the box on the right of the table below that correctly identifies the row showing which two vessels are arteries and which two are veins

Arteries Veins

A and 1 B and 2

A and 2 B and 1

B and 1 A and 2

B and 2 A and 1

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

54

(b) Blood moves towards the heart in veins Describe how blood is moved through veins

(3)

(c) Capillaries are involved in the exchange of materials between the blood and the surrounding body tissues Give two structural features of a capillary that enable it to exchange materials rapidly between the blood and the surrounding body tissues

1

2

(2)

(Total 6 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

55

34 (a) Daphnia heart rate increases when Daphnia are given the stimulant caffeine A student used this knowledge to estimate the caffeine content of three drinks

To do this she set up a calibration curve Initially she placed one Daphnia in pond water with no caffeine and counted the number of its heart beats in one minute She found this to be 180

She then placed the Daphnia in pond water with 10 mg of caffeine per 100 cm3 of pond water and recorded the time taken for 180 heart beats This was repeated for several different caffeine concentrations and the results are shown in the calibration curve below All measurements were taken at 15 degC

65

60

55

50

45

40

35

30

2580706050403020100

Tim

e ta

ken

for 1

80 h

eart

beat

s se

cond

s

Caffeine concentration mg per 100 cm pond water3

The student now repeated the study using the same Daphnia and keeping the temperature at 15 degC throughout but with instant coffee as the source of caffeine She recorded the time taken for 180 heart beats to occur She then repeated this using the two other drinks The results are shown in the table below Use the calibration curve to complete the third column of the table

Drink Time taken for 180 heart beats seconds

Caffeine concentration mg per 100 cm3

Instant coffee 33

Filter coffee 28

Tea 35 (3)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

56

(b) By using the same Daphnia throughout the investigation the student was able to control certain variables that could have affected her results

Give three variables that the student controlled by using the same Daphnia

1

2

3

(3)

(c) At the end of the investigation the student removed the Daphnia from the tea and placed it in pond water She then recorded its heart rate and found it to be 190 beats per minute

Suggest two reasons why the Daphnia heart rate was higher at the end of the investigation compared to the 180 beats per minute at the start

(2)

(Total 8 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

57

35 Describe two ways in which alveoli are adapted for their function

1

2

(Total 4 marks)

36 Read through the following passage on alveoli and gas exchange then write on the dotted lines the most appropriate word or words to complete the passage

During inspiration air reaches the alveoli through small tubes known as

The alveolar wall is composed of a

layer of epithelial cells which

the diffusion rate of oxygen from the alveolar air

into the surrounding the alveoli (Total 4 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

58

37 The diagram below shows a section through lung tissue as seen using a microscope

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

59

(a) Explain how the cells labelled A are adapted to their function

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (3)

(b) At rest the total blood flow through the lungs is about 5 dm3 per minute During exercise this increases to about 30 dm3 per minute Suggest how this increase in blood flow through the lungs is brought about

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip

helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip (1)

(Total 4 marks)

38 (a) The table below summarises four processes by which molecules can pass across membranes

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion

Facilitated diffusion

Osmosis

Active transport (4)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

60

(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion

(4)

(Total 8 marks)

39 The rate of diffusion of gases across an exchange surface is greater if the surface is thin and a concentration gradient is maintained across it

Describe how each of these factors is involved in respiratory gas exchange in the following

Alveoli in human lungs

(Total 5 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

61

40 The diagram below illustrates a small section of part of a lung responsible for gas exchange

Alveoli

Capillary network

X

Z

Y

(a) Write X Y or Z in the appropriate spaces in the table below

Structure Letter on diagram

Bronchiole

Branch of pulmonary artery

Branch of pulmonary vein (2)

(b) Describe how the structures in this diagram are adapted for rapid gas exchange

(4)

(Total 6 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

62

41 The diagram below represents the approximate concentrations of certain molecules inside an alveolus and a capillary in the lungs

8 oxygen7 carbon dioxide1 glucose

15 oxygen5 carbon dioxide0 glucose

alveolus

capillary

(a) State and explain which direction the oxygen and carbon dioxide molecules will move between the capillary and the alveolus

(2)

(b) Describe three ways in which the lungs are adapted for rapid gas exchange

1

2

3

(3)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

63

(c) People suffering from cystic fibrosis produce viscous (sticky) mucus and are often short of breath

(i) Explain why the mucus produced is viscous

(2)

(ii) Suggest why they are often short of breath

(2)

(Total 9 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

64

42 Describe how alveoli are adapted for the function of gas exchange

(Total 5 marks)

43 The rate of diffusion of gases across an exchange surface is greatest if the surface is thin and a concentration gradient is maintained across it

(a) Describe how each of these factors is involved in efficient gas exchange in the alveoli of a mammalian lung

(3)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

65

(b) Describe and explain the effect of cystic fibrosis on gas exchange

(2)

(c) The pedigree below shows the inheritance of cystic fibrosis (CF) in one family

Zac Jane

Samir Fiona Priya

Unaffected female

Unaffected male

Female with CF

Male with CF

James Nigel

With reference to the information in the pedigree answer the following questions

(i) Give the name of a female who is homozygous for the CF gene

(1)

(ii) Give the name of a male who is heterozygous for the CF gene

(1)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

66

(iii) If Fiona and Samir had a third child state the probability that this child would have cystic fibrosis

(1)

(d) Genetic screening can be used to identify the cystic fibrosis allele By considering contrasting ethical viewpoints discuss one reason in favour and one reason against genetic screening for cystic fibrosis

(4)

(Total 12 marks)

44 (a) During ventricular systole blood is forced out of the heart

Place a tick in the box ( ) below the column that correctly identifies three features that occur during ventricular systole

Three features

Atrioventricular valves closed open open closed

SAN pacemaker active not active active not active

Ventricular blood pressure

lower than atria

lower than atria

higher than atria

higher than atria

Place your tick in one of these four boxes

(1)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

67

(b) (i) When a doctor takes the blood pressure of a patient two values are found such as 11075 (110 over 75) Which value is the systolic pressure

(1)

(ii) Hypertension is a consistently and abnormally high blood pressure Give two factors that increase the risk of having hypertension

1

2 (2)

(c) It has been shown that for men aged 40 to 50 years old each rise of 10 units in their systolic blood pressure increases the risk of heart disease by 20

(i) Calculate the increased risk of heart disease in a 40 year old man with a systolic blood pressure 50 units higher than the average for his age

Answer (1)

(ii) Explain the meaning of the figure you have calculated in (c)(i)

(1)

(Total 6 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

68

45 The graph below shows death rates from coronary heart disease (CHD) in men from 1970 to 1995 in four countries

0

100

200

300

400

500

600

700

800

1970 1975 1980 1985 1990 1995

Year

Dea

th r

ate

de

aths

per

10

0 00

0

Finland

Italy

UK

Poland

(a) Describe the changes in death rates shown on the graph

(3)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

69

(b) The graph below shows the percentage of men from these countries in 1980 with high systolic blood pressure

0

10

20

30

40

50

60

70

80

Finland Italy UK Poland

Perc

enta

ge m

en w

ith h

igh

syst

olic

blo

od p

ress

ure

It has been suggested that there is a link between high blood pressure and deaths from CHD

(i) Using both graphs give two pieces of evidence to support this hypothesis

(2)

(ii) Suggest how the data shown in the graphs do not fully support this hypothesis

(2)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

70

(c) Suggest how high blood pressure can result in less oxygen reaching heart muscle

(3)

(Total 10 marks)

46 The diagram below shows an external view of the heart

(a) Name the blood vessels labelled W X Y and Z

W

X

Y

Z (2)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

71

(b) Describe and explain the events that occur during ventricular systole in the cardiac cycle

(4)

(c) The hypothesis that higher concentrations of caffeine will increase heart rate can be investigated practically using Daphnia (water fleas)

Describe a reliable procedure that could be used to test this hypothesis

(6)

(Total 12 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

72

47 (a) Blood vessels can be distinguished by their structure The table shows some structural

features for three blood vessels P Q and R Structural feature P Q R

Endothelium present

Small lumen relative to the thickness of the walls

Many elastic fibres present

Valves present

Identify the blood vessels P Q and R

P

Q

R (3)

(b) The diagram below shows changes in blood pressure as blood flows from the arteries to the veins

ARTERIES ARTERIOLES CAPILLARIES VENULES VEINS

direction of blood flow through circulation

Blo

od p

ress

ure

kPa

A

B

0

2

4

6

8

10

12

The blood pressure at point A is 105 kPa and the blood pressure at point B is 25 kPa Calculate the percentage decrease in the pressure as blood flows from A to B

Answer kPa (2)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)

73

(c) Explain the changes in blood pressure

(i) in the arteries

(ii) in the capillaries

(2)

(Total 7 marks)