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UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certificate of Education Advanced Subsidiary Level and Advanced Level

BIOLOGY 9700/11

Paper 1 Multiple Choice May/June 2011

1 hour Additional Materials: Multiple Choice Answer Sheet Soft clean eraser Soft pencil (type B or HB is recommended)

READ THESE INSTRUCTIONS FIRST

Write in soft pencil.

Do not use staples, paper clips, highlighters, glue or correction fluid.

Write your name, Centre number and candidate number on the Answer Sheet in the spaces provided unless this has been done for you.

There are forty questions on this paper. Answer all questions. For each question there are four possible answers A, B, C and D.

Choose the one you consider correct and record your choice in soft pencil on the separate Answer Sheet.

Read the instructions on the Answer Sheet very carefully.

Each correct answer will score one mark. A mark will not be deducted for a wrong answer.

Any rough working should be done in this booklet.

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1 A cell organelle measures 4 × 10 1 mm in diameter.

What is the diameter in µm?

A 4 × 101 µm B 4 × 102

µm C 4 × 103 µm D 4 × 104

µm 2 In the following table, which is the correct comparison between light and electron microscopes?

light microscope electron microscope

resolution magnification resolution magnification

A high high low low

B high low low high

C low high high low

D low low high high

3 Which structures are present in a typical plant cell?

centrioles cilia mitochondria vacuole

A � � � � key

B � � � � �= present

C � � � � �= absent

D � � � �

4 Plant cells are stained and then viewed through a light microscope.

Which structures would be clearly visible at a magnification of ×400?

A chloroplast grana

B lysosomes

C nucleoli

D ribosomes 5 Which type of cell will contain the highest proportion of single membrane-bound structures?

A ciliated epithelial cell

B goblet cell

C red blood cell

D smooth muscle cell

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6 Four different fruit juices, A, B, C and D, were tested with Benedict’s solution. A second sample of each juice was hydrolysed and tested with Benedict’s solution. The table shows the masses of the precipitates formed.

Which juice contains the greatest mass of non-reducing sugar?

mass of precipitate before hydrolysis

/ mg

mass of precipitate after hydrolysis

/ mg

A 30 55

B 55 55

C 65 85

D 70 80

7 Which molecular bonds will be broken by hydrolysis when a molecule of glycogen is converted to

glucose?

bonds

1,2 1,4 1,6

A � � � key

B � � � �= broken

C � � � �= unbroken

D � � �

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8 Which set of statements correctly describes haemoglobin?

A four polypeptide

chains, each containing a prosthetic group

iron ions can

associate with oxygen forming oxyhaemoglobin

in each chain,

hydrophobic R groups of amino acids point towards the centre of the molecule

at 50 % saturation,

two oxygen molecules are transported by the molecule

B polypeptide chains

interact to produce a globular chain

each chain contains

a prosthetic group of amino acids surrounding an iron ion

two identical alpha

chains and two identical beta chains

each chain can

transport an oxygen molecule

C polypeptide chains

interact to produce an almost spherical molecule

an iron ion is

present within each haem group

quaternary structure

of two alpha chains and two beta chains

each molecule can

transport a total of four oxygen atoms

D polypeptide chains

produce a loose helical shape, which curls to form a spherical molecule

iron ions in the

molecule can bind reversibly with oxygen

in each chain,

hydrophobic R groups of amino acids surround the iron ion

each molecule can

transport a total of eight oxygen atoms

9 Some foods contain ‘hydrogenated vegetable oils’. These are unsaturated fats that have been

converted to saturated fats.

Which property of the fats will have changed?

A Their hydrocarbon chains will fit together more closely.

B Their solubility in water will increase.

C They will have more double bonds in their molecules.

D They will remain liquid at room temperature. 10 Which rows show the chemical groups present in the biological molecules listed?

biological molecule

presence of carboxyl (COOH) groups

presence of two or more hydroxyl (OH) groups

1 amino acid yes no

2 β-glucose no yes

3 glycerol no no

4 fatty acid yes no

A 1, 2 and 3 B 1, 2 and 4 C 1, 3 and 4 D 2, 3 and 4

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11 Which correctly matches the functional and structural features of cellulose, collagen, glycogen or triglyceride?

structure

function fibrous molecule held

together by hydrogen bonds

branched chains

A cellulose

triglyceride

support

energy source

�

�

�

�

�

�

B collagen

cellulose

strengthening

support

�

�

�

�

�

�

C collagen

glycogen

strengthening

storage

�

�

�

�

�

�

D glycogen

triglyceride

storage

energy source

�

�

�

�

�

�

key �= true �= false

12 The breakdown of hydrogen peroxide to water and oxygen is catalysed by the enzyme catalase.

In an investigation into the effect of pH on the rate of reaction of catalase, potato cubes were added to hydrogen peroxide.

Which dependent variable should be recorded?

A the change in mass of the potato after a given time

B the pH of the solution at regular time intervals

C the number of potato cubes added at the start

D the volume of oxygen given off at regular time intervals 13 Which levels of protein structure can determine the specificity of an enzyme?

1 primary

2 secondary

3 tertiary

4 quaternary

A 1, 2, 3 and 4

B 1, 2 and 3 only

C 1, 2 and 4 only

D 3 and 4 only

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14 Some inhibitors of enzyme reactions bind to the enzyme / substrate complex.

Which statements about this type of inhibition are correct?

1 The active site changes shape.

2 The inhibitor is non-competitive.

3 The initial rate of reaction is reduced.

4 The maximum rate of reaction (Vmax) is increased.

A 1 and 2 only B 1 and 3 only C 2 and 3 only D 2, 3 and 4 only 15 What is correct for the cell surface membrane and membranes within cells?

A Both allow intracellular transport.

B Both are stabilised by glycoproteins.

C Both have sites for enzyme attachment.

D Both protect cells from the contents of lysosomes. 16 What supports the view that a membrane protein is involved in active transport?

A It allows movement of molecules across a membrane if concentration differences exist.

B It can only function if mitochondria are supplied with sufficient oxygen.

C It has a tertiary structure with a binding site with a specific shape.

D It is found in the cell surface membranes and the mitochondrial membranes.

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17 Strips of plant tissue were immersed in a range of sucrose solutions of different concentrations. Their lengths were measured before immersion and after 30 minutes.

The graph shows the ratio of initial length to final length.

1.4

1.2

1.0

0.8

0.6

0.40.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

sucrose concentration / mol dm–3

initial lengthfinal length

What is a correct description of the change in the cells and in their water potential as the sucrose concentration increases?

change in the cells change in the water potential

A less turgid more negative

B less turgid less negative

C more turgid less negative

D more turgid more negative

18 Which is always true of cytokinesis?

1 Cell organelles replicate.

2 Cell organelles are divided between two cells.

3 Nuclear envelope reforms.

A 1, 2 and 3 B 1 and 3 only C 2 only D 3 only 19 Which process occurs during prophase of the mitotic cell cycle in an animal cell?

A division of centromeres

B formation of chromosomes

C replication of DNA

D separation of centrioles

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20 The diagram shows how genetically identical frogs can be developed from unfertilised frog eggs. The diploid number (2n) for frogs is 26.

tadpole develops into frog

egg develops into tadpole

nucleus destroyed by ultra violet radiation

unfertilisedfrog egg

cell taken from frog W

V

X nucleus taken from cell and injected into egg

Which combination of numbers correctly identifies the number of chromosomes in each of the types of cell in the diagram?

V W X

A 13 13 26

B 13 26 13

C 13 26 26

D 26 26 13

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21 The mechanism of action of four drugs that inhibit DNA replication is stated below.

● Aphidicholine inhibits DNA polymerase.

● Cytarabine is converted into a molecule that can substitute for a DNA nucleotide and also inhibits DNA repair mechanisms.

● Epirubicin inhibits an enzyme involved in the unwinding of DNA and separation of strands.

● Hydroxycarbamide inhibits an enzyme involved in the production of deoxyribonucleotides.

Which row correctly matches a drug to an explanation of the mechanism of action?

explanation of mechanism of action

decreased pool of

available nucleotides inhibits

chain elongation

DNA strands not available as templates for transcription

DNA damaged during replication

and cell death occurs

exposed DNA template strands

unable to be copied

A aphidicholine epirubicin cytarabine hydroxycarbamide

B epirubicin cytarabine hydroxycarbamide aphidicholine

C hydroxycarbamide aphidicholine epirubicin cytarabine

D hydroxycarbamide epirubicin cytarabine aphidicholine

22 The following events occur during transcription.

1 Bonds break between complementary bases.

2 Bonds form between complementary bases.

3 Sugar-phosphate bonds form.

4 Free nucleotides pair with complementary nucleotides.

Before the mRNA leaves the nucleus, which events will have occurred twice?

A 1 and 2 only B 1, 3 and 4 only C 2, 3 and 4 only D 1, 2, 3 and 4 23 Which type of sugar and types of bonds are found in a DNA molecule?

type of sugar types of bonds

A non-reducing hydrogen and ionic

B non-reducing hydrogen and peptide

C reducing covalent and hydrogen

D reducing hydrogen and peptide

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24 In an animal cell, which process is dependent upon cell surface area and which process is dependent upon cell volume?

cell surface area cell volume

A carbon dioxide produced oxygen used

B glucose absorbed hormones detected

C hormones detected carbon dioxide produced

D oxygen used glucose absorbed

25 Which xerophytic adaptations reduce the water potential gradient?

1 rolled leaves

2 hairy leaves

3 sunken stomata

4 fewer stomata

5 fleshy leaves

A 1, 2, 3, 4 and 5

B 1, 2 and 3 only

C 1, 3 and 4 only

D 2, 4 and 5 only 26 During transpiration, what is the site of evaporation of water in the leaves?

A air spaces

B guard cell walls

C mesophyll cell walls

D stomata

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27 The photomicrograph shows a vascular bundle.

1

23

Which describes the relationship of water potential in the labelled cells?

A cell 3 less negative than cell 1

B cell 2 less negative than cell 3

C cell 3 more negative than cells 1 and 2

D cells 1, 2 and 3 have the same water potential

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28 The diagram represents the movement of water through a plant.

1 water enters the root

3 water vapour is lost from leaves

er 2 water passes up the stem

Which row identifies the processes involved during the stages of water movement shown?

cohesion and

adhesion transpiration osmosis

A 1 2 3

B 1 3 2

C 2 1 3

D 2 3 1

29 What is correct for tissue fluid?

phagocytes platelets protein concentration

compared to blood plasma

A � � higher key

B � � higher �= present

C � � lower �= absent

D � � lower

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30 What happens during ventricular diastole?

A All semilunar valves open.

B The atrio-ventricular valves open.

C The pressure in the atria rises above the pressure in the ventricles.

D The pressure in the left atrium rises more than the pressure in the right atrium. 31 Which row correctly describes the events during the cardiac cycle?

nerve impulses from

atrio-ventricular node (AVN) to nerve impulses from

Purkyne tissue (PT) to nerve impulses from

sino-atrial node (SAN) to

A SAN the ventricles AVN

B PT the atria PT

C PT the ventricles AVN

D SAN the atria PT

32 Which row correctly identifies the structure of an artery compared with a vein seen in transverse

section under a light microscope?

outer wall of

artery layer of muscles and elastic fibres

diameter of the lumen (hollow space)

A thicker thicker narrower

B thicker thinner wider

C thinner thicker narrower

D thinner thinner wider

33 In the lungs, oxygen and carbon dioxide pass through cell membranes by diffusion.

Which row is correct?

number of cell membranes diffused through by

oxygen from air carbon dioxide to air

A 3 2

B 3 2 or 3

C 5 4

D 5 4 or 5

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34 A student was asked to describe the differences between four microscope slides of sections taken from different parts of the gas exchange system.

slide 1 not present: cartilage, glands

present: few goblet cells, ciliated epithelial cells, smooth muscle

slide 2 present: incomplete cartilage rings, glands, goblet cells, ciliated epithelial cells, smooth muscle

slide 3 not present: cartilage, glands, goblet cells, smooth muscle present: squamous epithelial cells

slide 4 present: plates of cartilage, glands, goblet cells, ciliated epithelial cells, smooth muscle

Which is the correct identification of the parts of the gas exchange system?

slide 1 slide 2 slide 3 slide 4

A alveolus bronchiole bronchus trachea

B bronchiole bronchus alveolus trachea

C bronchiole trachea alveolus bronchus

D bronchus trachea bronchiole alveolus

35 A person suffering from mild emphysema stopped smoking cigarettes.

Why would this person’s health improve?

A goblet cells secrete more mucus, allowing a greater number of pathogens to be trapped

B increased numbers of phagocytic macrophages arrive in the lungs

C less atheroma build-up on the inner lining of arteries, increasing lumen diameter

D less carboxyhaemoglobin produced, increasing oxygen transport by haemoglobin 36 Which disease is not likely to be passed directly from parents to child?

A cholera

B malaria

C sickle cell anaemia

D tuberculosis

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37 The diagram shows one way of testing the effect of an antibiotic on bacteria.

petri dish withnutrient agar

containingbacteria

disc of filter papersoaked in antibiotic

colonies of bacteria

grown for5 weeks

diameter of zonemeasured everyweek for 5 weeks

The table shows the results of testing five different types of bacteria. Zones of less than 13 mm show the presence of resistant bacteria.

diameter of zone / mm type of bacteria week 1 week 2 week 3 week 4 week 5

1 24.10 21.90 19.00 17.60 14.30

2 18.60 15.40 12.20 9.00 0.00

3 17.90 12.80 12.40 11.10 10.90

4 19.40 15.30 13.20 8.10 0.00

5 22.00 21.00 20.50 20.40 20.40

Which statement can be supported by this data?

A Bacteria become more resistant to antibiotics over time.

B Only types 2, 3 and 4 of the bacteria show resistance to the antibiotic.

C The antibiotic can be used to treat all the types of bacteria.

D Type 5 of the bacteria can never become resistant to the antibiotic. 38 Smallpox has been eradicated, but not malaria or cholera.

Which statements correctly explain this?

1 Cholera bacteria in the intestines are not destroyed by antibiotics.

2 Plasmodium antigens change during the life cycle.

3 Smallpox antigens remain stable.

4 Vaccines only work against viruses.


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University of Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.

© UCLES 2011 9700/11/M/J/11

39 A square metre of grassland receives about 1 047 000 kJ of solar light energy each year.

The table shows what happens to this energy.

kJ

used in evaporation of water 523 500

transmitted to the ground 335 000

reflected by the leaves 165 000

used for growth 21 500

used for other life processes 1 500

respiratory heat losses 500

How much energy is used by the grass in photosynthesis?

A 2000 kJ B 19 500 kJ C 21 500 kJ D 23 500 kJ 40 Which process does not involve making nitrogen available to plants?

A ammonification

B denitrification

C nitrification

D nitrogen fixation

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BIOLOGY 9700/12












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1 Using a stage micrometer scale, one unit of an eyepiece graticule was calculated as 0.005 mm. The diameter of a spongy mesophyll cell was counted as 3.5 units on the eyepiece graticule.

What is the estimate of the diameter of the cell?

A 0.18 µm B 1.8 µm C 18.0 µm D 180 µm 2 Membranous sacs containing products of metabolism are formed by the endoplasmic reticulum in

cells.

Where are these products used?

A inside and outside the cell

B inside lysosomes only

C inside the cell only

D outside the cell only 3 Visking tubing is an artificial partially permeable membrane used to demonstrate diffusion.

Glucose molecules can pass through the pores in the membrane which are approximately 2.4 nm in diameter.

Which of the following could pass through the pores?

1 bacteria

2 haemoglobin

3 ribosomes

4 glycogen

A 2 only B 1 and 3 only C 2 and 4 only D none of these 4 Which of the structures are found in photosynthetic prokaryotes?

1 cell surface membrane

2 cellulose wall

3 mesosomes

4 ribosomes

5 chloroplasts

A 1, 2, 3 and 4 only

B 1, 2, 4 and 5 only

C 1, 3 and 4 only

D 2, 3 and 5 only

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5 A human aorta has a lumen width of 2 cm.

A human red blood cell has a diameter of 7 µm.

How many red blood cells could be laid end to end across the diameter of the aorta lumen?

A 2.9 × 10 3 B 2.9 × 10 2 C 2.9 × 102 D 2.9 × 103 6 Which polysaccharides are branched and which are unbranched?

branched unbranched

A amylose cellulose

B amylopectin cellulose

C cellulose amylose

D cellulose amylopectin

7 Three carbohydrate molecules are shown.

CH2OH

OH HO OH

OH

O

1

CH2OH

OH HO

OH

OH

O

2 3

CH2OH

CH2OH

OH

O

OH

OH

Which two molecules combine to form a molecule of sucrose?

A 1 and 2 B 1 and 3 C 2 and 3 D two of molecule 1 8 At which levels of protein structure do ionic bonds occur?

1 secondary

2 tertiary

3 quaternary

A 1 and 2 only B 1 and 3 only C 2 and 3 only D 1, 2 and 3

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9 Myoglobin is a protein with a similar function to haemoglobin. However, myoglobin does not have a quaternary structure.

Why does myoglobin not have a quaternary structure?

A Myoglobin does not contain a haem group.

B Myoglobin does not contain any alpha helices.

C Myoglobin has a fibrous rather than a globular structure.

D Myoglobin has only one polypeptide chain. 10 The diagram shows the structure of the amino acid cysteine.

H S C

H

HH

H

H

C C

O

N

OH

When two of these amino acids join together what bond(s) are formed?

A disulfide bonds only

B disulfide and peptide bonds

C hydrogen, disulfide and peptide bonds

D peptide bonds only 11 Which row describes a triglyceride?

hydrophilic insoluble in alcohol

A � � key

B � � �= correct

C � � �= incorrect

D � �

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12 The graph shows the activation energy of an enzyme-catalysed reaction and the same reaction without a catalyst.

energy

reaction

reactants

products

X

Y

Z

Which of the following shows the activation energy of the uncatalysed reaction?

A X + Y – Z B X + Z – Y C X + Y D Y + Z 13 Which of the following statements are true of all enzymes?

1 soluble in water

2 catalyse the breakdown of large molecules into smaller molecules

3 only have one active site

4 have a quaternary structure

A 1, 2 and 3 only

B 2, 3 and 4 only

C 1 only

D 4 only

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14 The graphs show the effects of temperature and pH on enzyme activity.

rate ofreaction

rate ofreaction

Q

P

R

S

temperature pH

Which statement explains the enzyme activity at the point shown?

A At P, hydrogen bonds are formed between enzyme and substrate.

B At Q, the kinetic energy of enzyme and substrate is highest.

C At R, peptide bonds in the enzyme begin to break.

D At S, the enzyme is completely denatured. 15 The diagram shows part of a cell surface membrane.

3 4 5

2

1

Which molecules have both hydrophobic and hydrophilic regions?

A 1 and 5 only

B 1, 3 and 5 only

C 1, 2, 4 and 5 only

D 2, 3 and 4 only

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16 Increasing which type of bond helps to increase the fluidity of the cell surface membrane?

A C — O — C

B C — N

C C C

D hydrogen 17 When cylinders of potato tissue were immersed in a 0.35 mol dm 3 sucrose solution, they showed

no change in mass.

What will happen when cylinders are immersed in a 0.1 mol dm 3 sucrose solution?

A The pressure potential of the cells will become more positive.

B The solute potential of the cell will become more negative.

C The water potential of the cells will become more negative.

D The water potential of the solution will become less negative. 18 The graph represents the changes in the quantity of DNA present in one nucleus at different

stages in the life cycle of a mammal.

DNA content/ arbitrary units

4

3

2

1

time

fertilisation

egg

X

Which stage takes place at X?

A interphase

B metaphase

C prophase

D telophase

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19 At which stage of mitosis do these events occur?

centromeres separate spiralisation and

condensation of DNA

A anaphase interphase

B anaphase prophase

C metaphase interphase

D metaphase telophase

20 During which process does only mitosis occur?

A the production of antibodies from B-lymphocyte memory cells

B the production of cancerous tissue in alveoli

C the production of gametes

D the production of root hairs

21 The table shows the tRNA anticodons for four amino acids.

amino acid anticodon (tRNA)

asparagine UUA

glutamic acid CUU

proline GGA

threonine UGG

A cell makes a polypeptide with the following amino acid sequence.

glutamic acid – asparagine – threonine – proline

What was the sequence of bases on the DNA from which this was formed?

A GGAAATACCCTT

B CAAAATACCCCT

C CTTTTATGGGGA

D CTTTTATCCGGA

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22 What does the enzyme RNA polymerase synthesise?

A a polypeptide from an mRNA template

B a strand of DNA from an mRNA template

C mRNA from a DNA template

D mRNA from a tRNA template 23 The diagram shows part of a DNA molecule.

A T

G C

C G

C G

How many hydrogen bonds are involved in holding these strands of DNA together?

A 11 B 9 C 8 D 4 24 Which features enable the aorta to withstand high pressure at ventricular systole?

A collagen fibres and elastin fibres

B collagen fibres and endometrium

C elastin fibres and large lumen

D smooth muscle and small lumen 25 There is a decreased partial pressure of oxygen at high altitude compared to sea level.

Which row is a correct description and reason for the response of the body to high altitude?

description reason

A

more red blood cells

because haemoglobin breaks

down more rapidly

B

red blood cells have genes

switched on

so red blood cells produce more

haemoglobin

C

oxygen dissociation curve shifts

to the right

to compensate for an increase

in oxygen unloading in tissues

D

percentage saturation of haemoglobin

with oxygen in lungs decreases

so more red blood cells are produced

to carry more haemoglobin

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26 What events occur during contraction of the left ventricle?

A The bicuspid valve opens and semilunar valve in the aorta opens.

B The bicuspid valve closes and semilunar valve in the aorta closes.

C The pressure in the left atrium becomes greater than the pressure in the left ventricle.

D The pressure in the left ventricle becomes greater than the pressure in the aorta. 27 Blood, tissue fluid and lymph each have a different composition.

Which row shows the composition of lymph?

contains

water contains

antibodies contains

lipid

A � � � key

B � � � �= present

C � � � �= absent

D � � �

28 Which processes are involved in transport in both phloem and xylem?

1 diffusion

2 mass flow

3 osmosis

A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only 29 Which features of xerophytes are adaptations to reduce water loss by transpiration?

rolled leaves fleshy leaves sunken stomata thick waxy cuticles

A � � � �

B � � � �

C � � � �

D � � � �

key

�= reduces water loss

�= no effect on water loss

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30 The graph shows the results of measuring the concentration of sucrose in the xylem, phloem and leaves of a plant during 24 hours.

06 00 18 00 00 0012 00time of day

sucrose concentration

phloem

leaves

xylem

Which conclusion can be drawn from these results?

A Osmosis moves water from the xylem to the phloem.

B Sucrose is actively transported into the phloem from the leaves.

C Sucrose is moved in both directions in the phloem.

D Xylem tissue uses sucrose as a source of energy. 31 Water that is present inside a root hair cell may leave the cell and pass to the xylem.

Through which pathway must the water travel?

A apoplast

B plasmodesmata

C symplast

D vacuoles 32 What are the approximate diameters of a trachea, an alveolus, a bronchiole and a bronchus?

trachea / mm alveolus / mm bronchiole / mm bronchus / mm

A 18 0.25 0.50 12

B 18 0.50 0.25 12

C 12 0.25 0.50 18

D 12 0.50 0.25 18

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33 What could occur as a result of inhaling the nicotine in tobacco smoke?

A cilia lining the respiratory tract are paralysed, causing an increase in the secretion of mucus from enlarged goblet cells

B diffusion into blood capillaries followed by the release of adrenaline, which increases blood pressure and heart rate

C diffusion into the epithelial cells of the respiratory tract, increasing the risk of mutation and acting as a potential carcinogen

D dissolves in the lining of the alveoli, causing a breakdown in the alveolar walls and a decrease in surface area for gas exchange

34 Which effects does emphysema have?

1 surface area to volume ratio of lungs decreases

2 distance of the diffusion pathway increases

3 volume of oxygen diffused per unit time decreases

A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only 35 Which of the diseases listed in the table are only treatable using antibiotics?

cholera measles TB

A � � � key

B � � � �= treatable

C � � � �= not treatable

D � � �

36 The diagram shows properties of diseases.

Which area of the diagram shows the properties that are common to both cholera and tuberculosis?

A

DC B

bacterial infectious

transmitted byairborne droplets

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37 The disease smallpox has been eradicated by a worldwide vaccination programme.

Which set of reasons correctly identifies the problems associated with planning vaccination programmes to eradicate other diseases?

TB malaria sickle cell anaemia

cholera

A invade gut cells

where immune system less

effective

genetically

inherited recessive condition

different

vaccines needed for active and

dormant-to- active forms

poor response

with malnourished

children; boosters then

required

B different stages

with different antigens;

invades body cells

poor response

with malnourished

children; boosters then

required

genetically


different



C different



different stages


invades body cells

genetically


invade gut cells


effective

D genetically


different



invade gut cells


effective

different stages


invades body cells

38 Anaerobic bacteria are abundant in waterlogged soils.

Which effect does this have on soil fertility and why?

soil fertility reason

A decreased bacteria convert nitrate to ammonia

B decreased bacteria convert nitrate to nitrogen gas

C increased bacteria cause decomposition

D increased bacteria cause nitrogen fixation

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39 What name is given to all the organisms in an area and their interactions with their environment?

A community

B ecosystem

C habitat

D niche 40 What is the function of nitrifying bacteria in the soil?

A oxidation of ammonium compounds to nitrates

B oxidation of nitrogen gas to nitrates

C reduction of ammonium compounds to nitrates

D reduction of nitrates to nitrites

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This document consists of 15 printed pages and 1 blank page.

IB11 06_9700_13/FP © UCLES 2011 [Turn over

*8956760756*


BIOLOGY 9700/13












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© UCLES 2011 9700/13/M/J/11

1 The diagram represents the movement of water through a plant.

1 water enters the root

3 water vapour is lost from leaves

er 2 water passes up the stem

Which row identifies the processes involved during the stages of water movement shown?

cohesion and

adhesion transpiration osmosis

A 1 2 3

B 1 3 2

C 2 1 3

D 2 3 1

2 Which xerophytic adaptations reduce the water potential gradient?

1 rolled leaves

2 hairy leaves

3 sunken stomata

4 fewer stomata

5 fleshy leaves

A 1, 2, 3, 4 and 5

B 1, 2 and 3 only

C 1, 3 and 4 only

D 2, 4 and 5 only

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3 The photomicrograph shows a vascular bundle.

1

23

Which describes the relationship of water potential in the labelled cells?

A cell 3 less negative than cell 1

B cell 2 less negative than cell 3

C cell 3 more negative than cells 1 and 2

D cells 1, 2 and 3 have the same water potential 4 Which row correctly identifies the structure of an artery compared with a vein seen in transverse

section under a light microscope?

outer wall of

artery layer of muscles and elastic fibres

diameter of the lumen (hollow space)

A thicker thicker narrower

B thicker thinner wider

C thinner thicker narrower

D thinner thinner wider

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© UCLES 2011 9700/13/M/J/11

5 Which row correctly describes the events during the cardiac cycle?

nerve impulses from

atrio-ventricular node (AVN) to nerve impulses from

Purkyne tissue (PT) to nerve impulses from

sino-atrial node (SAN) to

A SAN the ventricles AVN

B PT the atria PT

C PT the ventricles AVN

D SAN the atria PT

6 What happens during ventricular diastole?

A All semilunar valves open.

B The atrio-ventricular valves open.

C The pressure in the atria rises above the pressure in the ventricles.

D The pressure in the left atrium rises more than the pressure in the right atrium. 7 What is correct for tissue fluid?

phagocytes platelets protein concentration

compared to blood plasma

A � � higher key

B � � higher �= present

C � � lower �= absent

D � � lower

8 Which structures are present in a typical plant cell?

centrioles cilia mitochondria vacuole

A � � � � key

B � � � � �= present

C � � � � �= absent

D � � � �

9 A cell organelle measures 4 × 10 1 mm in diameter.

What is the diameter in µm?

A 4 × 101 µm B 4 × 102

µm C 4 × 103 µm D 4 × 104

µm

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10 Plant cells are stained and then viewed through a light microscope.

Which structures would be clearly visible at a magnification of ×400?

A chloroplast grana

B lysosomes

C nucleoli

D ribosomes 11 In the following table, which is the correct comparison between light and electron microscopes?

light microscope electron microscope

resolution magnification resolution magnification

A high high low low

B high low low high

C low high high low

D low low high high

12 What supports the view that a membrane protein is involved in active transport?

A It allows movement of molecules across a membrane if concentration differences exist.

B It can only function if mitochondria are supplied with sufficient oxygen.

C It has a tertiary structure with a binding site with a specific shape.

D It is found in the cell surface membranes and the mitochondrial membranes. 13 What is correct for the cell surface membrane and membranes within cells?

A Both allow intracellular transport.

B Both are stabilised by glycoproteins.

C Both have sites for enzyme attachment.

D Both protect cells from the contents of lysosomes.

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© UCLES 2011 9700/13/M/J/11

14 Strips of plant tissue were immersed in a range of sucrose solutions of different concentrations. Their lengths were measured before immersion and after 30 minutes.

The graph shows the ratio of initial length to final length.

1.4

1.2

1.0

0.8

0.6

0.40.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

sucrose concentration / mol dm–3

initial lengthfinal length

What is a correct description of the change in the cells and in their water potential as the sucrose concentration increases?

change in the cells change in the water potential

A less turgid more negative

B less turgid less negative

C more turgid less negative

D more turgid more negative

15 Which type of cell will contain the highest proportion of single membrane-bound structures?

A ciliated epithelial cell

B goblet cell

C red blood cell

D smooth muscle cell 16 A person suffering from mild emphysema stopped smoking cigarettes.

Why would this person’s health improve?

A goblet cells secrete more mucus, allowing a greater number of pathogens to be trapped

B increased numbers of phagocytic macrophages arrive in the lungs

C less atheroma build-up on the inner lining of arteries, increasing lumen diameter

D less carboxyhaemoglobin produced, increasing oxygen transport by haemoglobin

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17 A student was asked to describe the differences between four microscope slides of sections taken from different parts of the gas exchange system.

slide 1 not present: cartilage, glands

present: few goblet cells, ciliated epithelial cells, smooth muscle

slide 2 present: incomplete cartilage rings, glands, goblet cells, ciliated epithelial cells, smooth muscle

slide 3 not present: cartilage, glands, goblet cells, smooth muscle present: squamous epithelial cells

slide 4 present: plates of cartilage, glands, goblet cells, ciliated epithelial cells, smooth muscle

Which is the correct identification of the parts of the gas exchange system?

slide 1 slide 2 slide 3 slide 4

A alveolus bronchiole bronchus trachea

B bronchiole bronchus alveolus trachea

C bronchiole trachea alveolus bronchus

D bronchus trachea bronchiole alveolus

18 In the lungs, oxygen and carbon dioxide pass through cell membranes by diffusion.

Which row is correct?

number of cell membranes diffused through by

oxygen from air carbon dioxide to air

A 3 2

B 3 2 or 3

C 5 4

D 5 4 or 5

19 Which process does not involve making nitrogen available to plants?

A ammonification

B denitrification

C nitrification

D nitrogen fixation

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20 A square metre of grassland receives about 1 047 000 kJ of solar light energy each year.

The table shows what happens to this energy.

kJ

used in evaporation of water 523 500

transmitted to the ground 335 000

reflected by the leaves 165 000

used for growth 21 500

used for other life processes 1 500

respiratory heat losses 500

How much energy is used by the grass in photosynthesis?

A 2000 kJ B 19 500 kJ C 21 500 kJ D 23 500 kJ 21 During transpiration, what is the site of evaporation of water in the leaves?

A air spaces

B guard cell walls

C mesophyll cell walls

D stomata 22 Some inhibitors of enzyme reactions bind to the enzyme / substrate complex.

Which statements about this type of inhibition are correct?

1 The active site changes shape.

2 The inhibitor is non-competitive.

3 The initial rate of reaction is reduced.

4 The maximum rate of reaction (Vmax) is increased.

A 1 and 2 only B 1 and 3 only C 2 and 3 only D 2, 3 and 4 only

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23 Which levels of protein structure can determine the specificity of an enzyme?

1 primary

2 secondary

3 tertiary

4 quaternary

A 1, 2, 3 and 4

B 1, 2 and 3 only

C 1, 2 and 4 only

D 3 and 4 only 24 The breakdown of hydrogen peroxide to water and oxygen is catalysed by the enzyme catalase.

In an investigation into the effect of pH on the rate of reaction of catalase, potato cubes were added to hydrogen peroxide.

Which dependent variable should be recorded?

A the change in mass of the potato after a given time

B the pH of the solution at regular time intervals

C the number of potato cubes added at the start

D the volume of oxygen given off at regular time intervals 25 Which type of sugar and types of bonds are found in a DNA molecule?

type of sugar types of bonds

A non-reducing hydrogen and ionic

B non-reducing hydrogen and peptide

C reducing covalent and hydrogen

D reducing hydrogen and peptide

26 Which process occurs during prophase of the mitotic cell cycle in an animal cell?

A division of centromeres

B formation of chromosomes

C replication of DNA

D separation of centrioles

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27 Which is always true of cytokinesis?

1 Cell organelles replicate.

2 Cell organelles are divided between two cells.

3 Nuclear envelope reforms.

A 1, 2 and 3 B 1 and 3 only C 2 only D 3 only 28 The diagram shows how genetically identical frogs can be developed from unfertilised frog eggs.

The diploid number (2n) for frogs is 26.

tadpole develops into frog

egg develops into tadpole

nucleus destroyed by ultra violet radiation

unfertilisedfrog egg

cell taken from frog W

V

X nucleus taken from cell and injected into egg

Which combination of numbers correctly identifies the number of chromosomes in each of the types of cell in the diagram?

V W X

A 13 13 26

B 13 26 13

C 13 26 26

D 26 26 13

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29 The following events occur during transcription.

1 Bonds break between complementary bases.

2 Bonds form between complementary bases.

3 Sugar-phosphate bonds form.

4 Free nucleotides pair with complementary nucleotides.

Before the mRNA leaves the nucleus, which events will have occurred twice?

A 1 and 2 only B 1, 3 and 4 only C 2, 3 and 4 only D 1, 2, 3 and 4 30 The mechanism of action of four drugs that inhibit DNA replication is stated below.

● Aphidicholine inhibits DNA polymerase.

● Cytarabine is converted into a molecule that can substitute for a DNA nucleotide and also inhibits DNA repair mechanisms.

● Epirubicin inhibits an enzyme involved in the unwinding of DNA and separation of strands.

● Hydroxycarbamide inhibits an enzyme involved in the production of deoxyribonucleotides.

Which row correctly matches a drug to an explanation of the mechanism of action?

explanation of mechanism of action

decreased pool of

available nucleotides inhibits

chain elongation

DNA strands not available as templates for transcription

DNA damaged during replication

and cell death occurs

exposed DNA template strands

unable to be copied

A aphidicholine epirubicin cytarabine hydroxycarbamide

B epirubicin cytarabine hydroxycarbamide aphidicholine

C hydroxycarbamide aphidicholine epirubicin cytarabine

D hydroxycarbamide epirubicin cytarabine aphidicholine

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© UCLES 2011 9700/13/M/J/11

31 Four different fruit juices, A, B, C and D, were tested with Benedict’s solution. A second sample of each juice was hydrolysed and tested with Benedict’s solution. The table shows the masses of the precipitates formed.

Which juice contains the greatest mass of non-reducing sugar?

mass of precipitate before hydrolysis

/ mg

mass of precipitate after hydrolysis

/ mg

A 30 55

B 55 55

C 65 85

D 70 80

32 Which rows show the chemical groups present in the biological molecules listed?

biological molecule

presence of carboxyl (COOH) groups

presence of two or more hydroxyl (OH) groups

1 amino acid yes no

2 β-glucose no yes

3 glycerol no no

4 fatty acid yes no


33 Some foods contain ‘hydrogenated vegetable oils’. These are unsaturated fats that have been

converted to saturated fats.

Which property of the fats will have changed?

A Their hydrocarbon chains will fit together more closely.

B Their solubility in water will increase.

C They will have more double bonds in their molecules.

D They will remain liquid at room temperature.

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34 Which molecular bonds will be broken by hydrolysis when a molecule of glycogen is converted to glucose?

bonds

1,2 1,4 1,6

A � � � key

B � � � �= broken

C � � � �= unbroken

D � � �

35 Which correctly matches the functional and structural features of cellulose, collagen, glycogen or

triglyceride?

structure

function fibrous molecule held

together by hydrogen bonds

branched chains

A cellulose

triglyceride

support

energy source

�

�

�

�

�

�

B collagen

cellulose

strengthening

support

�

�

�

�

�

�

C collagen

glycogen

strengthening

storage

�

�

�

�

�

�

D glycogen

triglyceride

storage

energy source

�

�

�

�

�

�

key �= true �= false

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© UCLES 2011 9700/13/M/J/11

36 Which set of statements correctly describes haemoglobin?

A four polypeptide

chains, each containing a prosthetic group

iron ions can

associate with oxygen forming oxyhaemoglobin

in each chain,

hydrophobic R groups of amino acids point towards the centre of the molecule

at 50 % saturation,

two oxygen molecules are transported by the molecule

B polypeptide chains

interact to produce a globular chain

each chain contains

a prosthetic group of amino acids surrounding an iron ion

two identical alpha

chains and two identical beta chains

each chain can

transport an oxygen molecule

C polypeptide chains

interact to produce an almost spherical molecule

an iron ion is

present within each haem group

quaternary structure

of two alpha chains and two beta chains

each molecule can

transport a total of four oxygen atoms

D polypeptide chains

produce a loose helical shape, which curls to form a spherical molecule

iron ions in the

molecule can bind reversibly with oxygen

in each chain,

hydrophobic R groups of amino acids surround the iron ion

each molecule can

transport a total of eight oxygen atoms

37 Smallpox has been eradicated, but not malaria or cholera.

Which statements correctly explain this?

1 Cholera bacteria in the intestines are not destroyed by antibiotics.

2 Plasmodium antigens change during the life cycle.

3 Smallpox antigens remain stable.

4 Vaccines only work against viruses.

A 1, 2 and 3 B 1, 2 and 4 C 1, 3 and 4 D 2, 3 and 4 38 Which disease is not likely to be passed directly from parents to child?

A cholera

B malaria

C sickle cell anaemia

D tuberculosis

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39 The diagram shows one way of testing the effect of an antibiotic on bacteria.

petri dish withnutrient agar

containingbacteria

disc of filter papersoaked in antibiotic

colonies of bacteria

grown for5 weeks

diameter of zonemeasured everyweek for 5 weeks

The table shows the results of testing five different types of bacteria. Zones of less than 13 mm show the presence of resistant bacteria.

diameter of zone / mm type of bacteria week 1 week 2 week 3 week 4 week 5

1 24.10 21.90 19.00 17.60 14.30

2 18.60 15.40 12.20 9.00 0.00

3 17.90 12.80 12.40 11.10 10.90

4 19.40 15.30 13.20 8.10 0.00

5 22.00 21.00 20.50 20.40 20.40

Which statement can be supported by this data?

A Bacteria become more resistant to antibiotics over time.

B Only types 2, 3 and 4 of the bacteria show resistance to the antibiotic.

C The antibiotic can be used to treat all the types of bacteria.

D Type 5 of the bacteria can never become resistant to the antibiotic. 40 In an animal cell, which process is dependent upon cell surface area and which process is

dependent upon cell volume?

cell surface area cell volume

A carbon dioxide produced oxygen used

B glucose absorbed hormones detected

C hormones detected carbon dioxide produced

D oxygen used glucose absorbed

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DC (KN/SW) 34108/3© UCLES 2011 [Turn over

UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONSGeneral Certificate of EducationAdvanced Subsidiary Level and Advanced Level


Write your Centre number, candidate number and name in the spaces provided at the top of the page.Write in dark blue or black ink.You may use a soft pencil for any diagrams, graphs or rough working.Do not use red ink, staples, paper clips, highlighters, glue or correction fluid.DO NOT WRITE IN ANY BARCODES.

Answer all questions.At the end of the examination, fasten all your work securely together.The number of marks is given in brackets [ ] at the end of each question or part question.

*6723760386*

BIOLOGY 9700/21

Paper 2 Structured Questions AS May/June 2011

1 hour 15 minutes

Candidates answer on the Question Paper.

No Additional Materials are required.

For Examiner’s Use

1

2

3

4

5

6

Total

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9700/21/M/J/11© UCLES 2011

ForExaminer’s

Use

Answer all the questions.

1 Fig. 1.1 is an electron micrograph of cells from the ciliated epithelium of the trachea.

A

C

A

10 µm

B

Fig. 1.1

(a) Calculate the magnification of the electron micrograph in Fig. 1.1.

Show your working and express your answer to the nearest whole number.

magnification × .................................................. [2]

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9700/21/M/J/11© UCLES 2011 [Turn over

ForExaminer’s

Use

(b) Explain how the cells labelled A and the structures labelled B in Fig. 1.1 protect the lining of the trachea.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [4]

(c) Cells, such as C, at the base of the epithelium of the trachea divide by mitosis.

Describe the changes that occur within the cell between the beginning of prophase and the end of metaphase.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [5]

[Total: 11]

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ForExaminer’s

Use

2 (a) Carbon dioxide is transported in the blood in various forms.

Describe how carbon dioxide molecules reach red blood cells from respiring cells.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [2]

Fig. 2.1 shows part of a capillary network and some cells of the surrounding tissue.

X Y

venuleend

arterioleend

Fig. 2.1

(b) State three ways in which the blood at Y differs from the blood at X other than in the concentration of carbon dioxide.

1. ......................................................................................................................................

2. ......................................................................................................................................

3. .................................................................................................................................. [3]

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ForExaminer’s

Use

An enzyme in red blood cells catalyses the reaction between carbon dioxide and water as blood flows through respiring tissues.

CO2 + H2O H2CO3

enzyme

H+ + HCO3–

(c) (i) Name the enzyme that catalyses this reaction.

.............................................................................................................................. [1]

(ii) Explain the significance of this reaction in the transport of carbon dioxide.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [3]

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ForExaminer’s

Use

(d) Fig. 2.2 shows the effect of increasing the carbon dioxide concentration on the oxygen haemoglobin dissociation curve.

00

20

40

60

80

100

1 2 3 4 5partial pressure of oxygen / kPa

percentagesaturation ofhaemoglobinwith oxygen

6 7 8 9 10 11 12

partial pressure CO21.0 kPa

partial pressure CO21.5 kPa

Fig. 2.2

(i) State the percentage saturation of haemoglobin with oxygen at a partial pressure of 5 kPa of oxygen when the partial pressure of carbon dioxide is:

1.0 kPa ......................................................................................................................

1.5 kPa .................................................................................................................. [1]

(ii) The percentage saturation of haemoglobin with oxygen decreases as the partial pressure of carbon dioxide increases.

Explain how this happens.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [2]

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ForExaminer’s

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(iii) Name the effect of increasing carbon dioxide concentration on the oxygen dissociation curve.

.............................................................................................................................. [1]

(iv) Explain the importance of the effect of carbon dioxide on haemoglobin as shown in Fig. 2.2.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [3]

[Total: 16]

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Use

3 A molecule of messenger RNA (mRNA) was produced during the transcription of a gene. Part of the template sequence of DNA was ATGC.

Fig. 3.1 shows the part of the molecule of messenger RNA corresponding to that sequence of four bases.

DO

O

N

N

HH

H

H

H

H H

H

H

H H

H

H

H H

H

H

HHN

H

N

NN

N

HH

H

O

N

N

H

H

NHH

O

N

N

NN

N

H

H

H

H

O

OH

OH

OH

OHO

P

O

O

O

O CH2

P

O

O

O

O CH2

P

O

O

O

O CH2

P

O

O

O

O CH2O

O

O

E

guanine

G

F

Fig. 3.1

(a) Name the parts of the mRNA molecule shown in Fig. 3.1 labelled D, E, F and G.

D ......................................................................................................................................

E ......................................................................................................................................

F .......................................................................................................................................

G .................................................................................................................................. [4]

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ForExaminer’s

Use

(b) Complete the table to show three ways in which mRNA differs from DNA.

mRNA DNA

1

2

3

[3]

(c) Describe the role of mRNA after it leaves the nucleus and enters the cytoplasm of a eukaryotic cell.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [4]

[Total: 11]

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4 The enzyme sucrase catalyses the breakdown of the glycosidic bond in sucrose.

A student investigated the effect of increasing the concentration of sucrose on the rate of activity of sucrase.

Ten test-tubes were set up with each containing 5 cm3 of different concentrations of a sucrose solution. The test-tubes were placed in a water bath at 40 °C for ten minutes. A flask containing a sucrase solution was also put into the water bath.

After ten minutes, 1 cm3 of the sucrase solution was added to each test-tube. The reaction mixtures were kept at 40 °C for a further ten minutes.

After ten minutes, the temperature of the water bath was raised to boiling point. Benedict’s solution was added to each test-tube. The time taken for a colour change was recorded and used to calculate rates of enzyme activity.

The results are shown in Fig. 4.1.

00

2

4

6

8

10

12

20 40 60concentration of sucrose / g dm–3

rate of enzymeactivity

/ arbitrary units

80 100

Fig. 4.1

(a) (i) Name the type of reaction catalysed by sucrase.

.............................................................................................................................. [1]

(ii) Explain why the temperature of the water was raised to boiling point.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [2]

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ForExaminer’s

Use

(b) Describe and explain the results shown in Fig. 4.1.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [5]

[Total: 8]

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9700/21/M/J/11© UCLES 2011

5 Fig. 5.1 shows five different biological molecules.

CH2OH

H O

O

O

OHH

H

H OH CH2OH

H

CH2OH

H

H

H O

OHH

H

H OH

H O

O

O

OHH

H

H OH

CH2OH

C O

O OOHH

H

H OH

CH2OH

O

OHH

H

H OH

H H

O

CH2OH

H O

OOHH

H

H OH

CH2OH

O

OHH

H

H OH

H H H

O

CH2OH

H O

OOHH

H

H OH

CH2OH

O

OHH

H

H OH

H H

O

H H

O

CH2

O

O

OHH

H

H OH

CH2OH

O

OHH

H

H OH

H H

O O

CH2OH

O

OHH

H

H OH

H H

O

CH2OH

O

OHH

H

H OH

H H H

H

O

CH2OHO

OH

OH

HO O

CH2

CH2

CH

C O

HN

OH

CH2

CH

CH

HC

C

OH

CC

O

H H

O

OH

N C

H

HC

C

CO

O

O–

O–

C

H H

H

C

CH3

H OH H

H NN

C C

CH H

H

CH H

CH

J

K

L

M

Fig. 5.1

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ForExaminer’s

Use

Complete Table 5.1 by indicating which molecule matches each statement.

You may use each letter (H to M) once, more than once or not at all.

You should write only one letter in each box.

Table 5.1

statement letter

contains peptide bonds

part of the molecule forms the hydrophobic part of cell membranes

contains 1-4 and 1-6 glycosidic bonds

forms the primary structure of a protein

used for energy storage in plants

forms a helical structure

the sub-unit molecule is β-glucose

[Total: 7]

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ForExaminer’s

Use

6 Measles is a common viral infection. A vaccine has been available for measles since the 1960s. There are vaccination programmes for many diseases including measles. Babies are born with a passive immunity to measles so the vaccine is not given in the first few months after birth.

(a) Explain how active immunity differs from passive immunity.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [3]

(b) Explain why the vaccine for measles is not given in the first few months of a child’s life.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [2]

The World Health Organization (WHO) publishes data on the vaccination programmes for infectious diseases. The WHO recommends vaccination rates of over 90% of children.

Each health authority in a country reports its success in vaccinating children in their district. The WHO uses these figures to estimate the percentage of districts in each country that vaccinate 90% of children against measles.

The WHO also collects statistics on death rates of children under the age of 5 from all causes, including infectious diseases.

Fig. 6.1 shows these statistics for 24 countries for the year 2007.

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ForExaminer’s

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00

50

100

150

200

250

300

10 20 30 40 50 60 70 80 90 100percentage of districts in each country vaccinating

90% of children against measles

mortality rate ofchildren under 5

years of age/ deaths per

1000 children

Fig. 6.1

(c) Use the information in Fig. 6.1 to explain why the WHO recommends immunisation of 90% of children.

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[Total: 7]

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Copyright Acknowledgements:

Fig. 1.1 © Image taken by Prof. H. Wartenberg from Dr. Jastrow’s electron microscope atlas on http://www.drjastrow.de.

Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity.


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DC (SM/CGW) 34109/2© UCLES 2011 [Turn over


*8436799160*

BIOLOGY 9700/22

Paper 2 Structured Questions AS May/June 2011

1 hour 15 minutes




Write your Centre number, candidate number and name in the spaces provided at the top of this page.Write in dark blue or black ink.You may use a soft pencil for any diagrams, graphs, or rough working.Do not use red ink, staples, paper clips, highlighters, glue or correction fluid.DO NOT WRITE IN ANY BARCODES.



1

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1 Fig. 1.1 is a photomicrograph of a root tip of onion, Allium cepa, showing cells in interphase and in stages of mitosis.

C

D

B

A

Fig. 1.1

(a) Name the stages of mitosis shown in cells A, B and C.

A ......................................................................................................................................

B ......................................................................................................................................

C .................................................................................................................................. [3]

(b) Suggest why the cells labelled D are smaller than most of the other cells in Fig. 1.1.

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [1]

(c) Interphase is often described as a ‘resting stage’.

Explain why the term ‘resting stage’ is not an appropriate description for cells in interphase.

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [2]

[Total: 6]

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2 Read the passage below. Parts of the passage are in bold type. These are examples of ecological terms and are labelled A to F.

A class of students carried out an ecological study of a defined area of seashore (A) in Brittany, France. One group decided to study a rockpool (B) and recorded information such as the oxygen concentration and temperature of the seawater (C). After investigating all the different living organisms (D) present in the rockpool, the students decided to study in more detail the group of limpets, Patella vulgata (E). They collected information about the role of the limpets within the rockpool, including interactions with other organisms (F). For example, limpets grazed on green seaweeds, while the shore crab, Carcinus maenas, fed on small limpets.

(a) State the correct letter, A to F, from the passage above that corresponds to each of the ecological terms below.

habitat

ecosystem

abiotic component

ecological niche

population

community

[4]

(b) State the trophic levels to which each of the organisms named in the passage belong and outline the energy losses that occur in the food chain.

..........................................................................................................................................

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[Total: 8]

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3 (a) Explain how the structure of red blood cells is suited to their function of transporting oxygen to body tissues.

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...................................................................................................................................... [3]

(b) The circulating red blood cell is metabolically active but only lives for about 120 days. During this time, some important enzymes are gradually broken down and this may contribute to the death of the cell.

Explain why the red blood cell is not able to replace important enzymes that have been broken down.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [2]

(c) Red blood cells are broken down by phagocytic cells in the liver and spleen. The haemoglobin is broken down into haem and globin before further processing. Some of the components of haemoglobin are re-used in the body.

(i) Name the mineral ion released from the breakdown of haem.

.............................................................................................................................. [1]

(ii) State the products of globin hydrolysis.

.............................................................................................................................. [1]

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Haemoglobin plays an important role in carrying oxygen and carbon dioxide.

Fig. 3.1 summarises some of the events that occur as blood enters a capillary located in an area of actively respiring cells.

CO2 CO2 Cl – Cl –

HbCO2

H2CO3

H2O

H2Ored bloodcell

blood plasmacapillaryendothelium

tissuefluid

respiringtissue

+

X

HbO8

Hb HCO3– HCO3

–

HHb

H+

CO2

4O2 4O2

Fig. 3.1

(d) State the name of the enzyme that catalyses the reaction occurring at X.

...................................................................................................................................... [1]

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(e) With reference to Fig. 3.1, describe and explain how carbon dioxide (CO2) andhydrogen ions (H+) play a role in the unloading of oxygen from haemoglobin.

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[Total: 13]

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4 Tuberculosis (TB) is an infectious disease that kills about three million people worldwide each year.

(a) Name the pathogenic organism that causes tuberculosis.

...................................................................................................................................... [1]

Fig. 4.1 is a transmission electron micrograph of the organism that causes tuberculosis.

XX

Y

Fig. 4.1

(b) (i) The actual length of the cell between X and Y in Fig. 3.1 is 2 µm.

Calculate the magnification of the electron micrograph.

Show your working and give your answer to the nearest whole number.

magnification × .......................... [2]

(ii) The organism that causes tuberculosis is a prokaryote. State three features of prokaryotes.

1. ...............................................................................................................................

2. ...............................................................................................................................

3. ........................................................................................................................... [3]

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In the 1940s, the use of antibiotics led to a steady decrease in the number of new cases of tuberculosis. However, in many developed countries, the number of new cases stopped decreasing in the mid-1980s and is now increasing.

(c) (i) State one factor, other than drug therapy, that contributed to the steady decrease in the number of new cases of tuberculosis.

.............................................................................................................................. [1]

(ii) Outline three reasons why, in many developed countries, the number of new cases of tuberculosis is now increasing.

1. ...............................................................................................................................

..................................................................................................................................

2. ...............................................................................................................................

..................................................................................................................................

3. ...............................................................................................................................

.............................................................................................................................. [3]

(d) Streptomycin was the first antibiotic to be discovered that was effective against the pathogen that causes tuberculosis. Streptomycin causes the death of the pathogen by binding to ribosomes and inhibiting protein synthesis.

(i) Suggest two ways in which streptomycin acts at ribosomes to inhibit protein synthesis.

1. ...............................................................................................................................

..................................................................................................................................

..................................................................................................................................

2. ...............................................................................................................................

..................................................................................................................................

.............................................................................................................................. [2]

(ii) Streptomycin does not harm mammalian cells.

Suggest an explanation for this.

..................................................................................................................................

.............................................................................................................................. [1]

[Total: 13]

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5 (a) Fig. 5.1 represents a molecule of a triglyceride.

Name the components A and C and name the bond B.

Write your answers on the dotted lines provided in Fig. 5.1.

A .........................................................

B .........................................................

C .........................................................

Fig. 5.1 [3]

(b) A phospholipid is sometimes described as a modified triglyceride.

(i) State how the structure of a phospholipid differs from a triglyceride.

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [2]

(ii) Explain how a phospholipid is suited to its role in cell membranes.

..................................................................................................................................

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.............................................................................................................................. [3]

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A student carried out an investigation into the digestion of triglycerides using lipase.

Ten cm3 of olive oil, adjusted to pH 8.0, was added to a test-tube, which was then put in a water bath at 37 °C for ten minutes.

One cm3 of lipase solution was incubated at the same temperature in a separate test-tube before being added to the olive oil.

The initial pH of the reaction mixture was measured using a pH meter. The pH was recorded at five minute intervals for 60 minutes.

(c) Suggest why the olive oil was adjusted to pH 8.0 before the lipase was added.

...................................................................................................................................... [1]

(d) Fig. 5.2 shows the results of the investigation.

06

7

8

5 10 15 20 25 30

time / min

pH

35 40 45 50 55 60

Fig. 5.2

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With reference to Fig. 5.2,

(i) describe the results of the investigation

..................................................................................................................................

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..................................................................................................................................

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..................................................................................................................................

.............................................................................................................................. [2]

(ii) explain the results of the investigation.

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[Total: 15]

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6 Leaves of tobacco plants, Nicotiana spp, have a high concentration of nicotine, the addictive component of tobacco smoke. Scientists are continually seeking ways to produce tobacco plants that have reduced nicotine content.

(a) Describe and explain the effects of nicotine on the cardiovascular system that can contribute to a person developing coronary heart disease.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

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..........................................................................................................................................

...................................................................................................................................... [4]

(b) The production of low-nicotine cigarettes and cigars is considered a strategy that may reduce the harmful effects of smoking.

Explain whether or not you agree with this statement.

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [1]

[Total: 5]

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Fig. 4.1 Pasieka/Science Photo Library


University of Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of he University of Cambridge.

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DC (NF/JG) 34112/3© UCLES 2011 [Turn over


*1134123604*

BIOLOGY 9700/23

Paper 2 Structured Question AS May/June 2011

1 hour 15 minutes




Write your Centre number, candidate number and name in the spaces provided at the top of this page.Write in dark blue or black ink.You may use a soft pencil for any diagrams, graphs or rough working.Do not use red ink, staples, paper clips, highlighters, glue or correction fluid.DO NOT WRITE IN ANY BARCODES.



1

2

3

4

5

6

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1 Fig. 1.1 shows a stage in the mitotic cell cycle in an animal cell.

Fig. 1.1

(a) (i) Name the stage of mitosis shown in Fig. 1.1.

............................................................................................................................. [1]

(ii) State three features which are characteristic of the stage of mitosis shown in Fig. 1.1.

1. ...............................................................................................................................

..................................................................................................................................

2. ...............................................................................................................................

..................................................................................................................................

3. ...............................................................................................................................

............................................................................................................................. [3]

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(b) Explain the importance of mitosis in organisms.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..................................................................................................................................... [3]

(c) In many multicellular organisms, such as mammals, the time taken for the mitotic cell cycle varies considerably between different tissues, but is very carefully controlled in each cell.

Suggest the importance of this control in mammals.

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..................................................................................................................................... [2]

[Total: 9]

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2 (a) Complete the table to show three ways in which the structure of DNA differs from RNA.

DNA RNA

1

2

3

[3]

(b) Table 2.1 shows two messenger RNA (mRNA) codons. Fill in the complementary transfer RNA (tRNA) anticodons in the spaces provided.

Table 2.1

mRNA codons GCG ACA

complementary tRNA anticodons

[2]

(c) Calculate the minimum number of DNA nucleotides necessary to code for a polypeptide with 238 amino acids.

Show your working.

answer .............................. nucleotides [2]

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(d) Describe the role played by tRNA in polypeptide synthesis.

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[Total: 11]

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3 (a) Plants take in mineral ions through their root hair cells. This may happen by a process which moves the ions from a low concentration in the soil to a higher concentration in the root hair cell.

(i) Name and describe this process by which mineral ions are taken in.

name ........................................................................................................................

description ................................................................................................................

..................................................................................................................................

..................................................................................................................................

............................................................................................................................. [3]

(ii) Phosphate is an example of an ion transported in this way. State one use for this ion in plant cells.

..................................................................................................................................

............................................................................................................................. [1]

Fig. 3.1 is a plan diagram of a transverse section of a plant root.

Fig. 3.1

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(b) (i) Write the letter W on Fig. 3.1 in the area where cells are specialised for the transport of water and mineral ions. [1]

(ii) Water is also absorbed from the soil by the root hair cells.

Outline the mechanism by which this occurs.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

............................................................................................................................. [2]

(iii) Describe the pathway taken by water as it passes from the root hair cells into the cells which are specialised for transport of water and mineral ions.

..................................................................................................................................

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[Total: 11]

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4 In mammals, haemoglobin is used to transport oxygen and myoglobin is used to store oxygen in muscles.

Fig. 4.1 shows the oxygen dissociation curves for myoglobin, fetal haemoglobin and adult haemoglobin.

2 4 6 8 10 12 140

20

0

40

60

80

100

percentagesaturation

with oxygen

partial pressure of oxygen / kPa

fetalhaemoglobin

adulthaemoglobin

myoglobin

Fig. 4.1

(a) (i) Name the cells in which haemoglobin is found.

............................................................................................................................. [1]

(ii) Use Fig. 4.1 to determine the percentage saturation of myoglobin and adult haemoglobin when the partial pressure of oxygen is 3 kPa.

myoglobin .................................................................................................................

adult haemoglobin ............................................................................................... [1]

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(iii) There is a large difference between the percentage saturation of myoglobin and that of adult haemoglobin at low partial pressures of oxygen. Suggest reasons for this.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

............................................................................................................................. [2]

(b) Fetal haemoglobin has a different oxygen binding affinity to that of adult haemoglobin, as shown in Fig. 4.1. Normally, after birth, the production of the fetal form stops and the adult form is produced.

In a rare condition known as Hereditary Persistence of Fetal Haemoglobin (HPFH), fetal haemoglobin continues to be produced well into adulthood in addition to adult haemoglobin. This condition, however, usually lacks any symptoms.

(i) Explain, with reference to Fig. 4.1, the significance of the difference in oxygen binding affinity between fetal and adult haemoglobin.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

............................................................................................................................. [2]

(ii) Suggest why HPFH usually lacks symptoms.

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..................................................................................................................................

............................................................................................................................. [1]

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(c) Sketch on Fig. 4.2 the dissociation curve you would expect for adult haemoglobin if the concentration of carbon dioxide is increased. [2]

2 4 6 8 10 12 140

20

0

40

60

80

100

percentagesaturation ofhaemoglobinwithoxygen

partial pressure of oxygen / kPa

adulthaemoglobin

Fig. 4.2

[Total: 9]

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5 Fig. 5.1 is an electron micrograph of a transverse section through part of a plant stem.

A

Fig. 5.1

(a) Name structure A.

..................................................................................................................................... [1]

(b) Specialised cells visible in Fig. 5.1 are involved in transporting assimilates through the plant from source to sink.

(i) Name one assimilate transported by these cells.

............................................................................................................................. [1]

(ii) Give one example of a source and one example of a sink.

source ......................................................................................................................

sink ...................................................................................................................... [2]

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(c) Describe how the assimilate you have named in (b)(i) is transported from the source to the sink.

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(d) Aphids are insects with mouthparts adapted to penetrating the cells of plants which transport assimilates.

Suggest why aphids feed specifically from these cells.

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..................................................................................................................................... [1]

[Total: 10]

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6 In anaerobic soil, bacteria, such as Pseudomonas stutzeri, can use nitrate ions (NO3–) as a

source of oxygen for their respiration. The word equation below summarises the process:

glucose + nitrate water + carbon dioxide + nitrogen

(a) (i) State the name of this process in the nitrogen cycle.

............................................................................................................................. [1]

(ii) In agriculture, this reaction can be undesirable. Explain why.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

............................................................................................................................. [2]

High concentrations of nitrate ions in drinking water obtained from rivers and lakes can be toxic, especially to infants. These nitrate ions enter rivers and lakes dissolved in water which drains from the soil.

(b) (i) Name the process, carried out by soil bacteria, which produces nitrate ions.

............................................................................................................................. [1]

(ii) Suggest how bacteria, such as Pseudomonas stutzeri, can be used in the process of purifying water for drinking.

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............................................................................................................................. [2]

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(c) In recent years there has been an increase in flooding of agricultural land worldwide.

Explain why crop yields are often significantly reduced even after the flood water has drained away.

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[Total: 10]

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Fig. 1.1 Michael Abbey/Science Photo Library.Fig. 5.1 J. C. Revy, ISM/Science Photo Library.



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DC (CW/DJ) 31753/6© UCLES 2011 [Turn over



Write your Centre number, candidate number and name on all the work you hand in.Write in dark blue or black ink.You may use a pencil for any diagrams, graphs or rough working.Do not use red ink, staples, paper clips, highlighters, glue or correction fluid.DO NOT WRITE IN ANY BARCODES.

Answer all questions.

You may lose marks if you do not show your working or if you do not use appropriate units.

At the end of the examination, fasten all your work securely together.The number of marks is given in brackets [ ] at the end of each question or part question.

*1918989739*

BIOLOGY 9700/31

Advanced Practical Skills 1 May/June 2011

2 hours


Additional Materials: As listed in the Confidential Instructions.


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You are reminded that you have only one hour for each question in the practical examination.

You should:

• Read carefully through the whole of each question.

• Plan your use of the time to make sure that you finish all the work that you would like to do.

You will gain marks for recording your results according to the instructions.

1 Enzyme E catalyses the hydrolysis of starch to glucose. The end-point of the reaction can be found by measuring the time taken for all the starch to

be hydrolysed.

You are required to investigate the effect of the independent variable, copper sulfate concentration, on enzyme E.

You are provided with:

labelled contents hazard concentration/ %

volume/ cm3

E amylase solution irritant 1 10

S starch solution none 1 50

C copper sulfate solution

harmfulirritant

0.03 20

W distilled water none – 100

iodine iodine in potassium iodide solution

irritant – 50

Copper sulfate can inhibit enzyme E. The extent of inhibition depends on the concentration of the copper sulfate solution. A student

investigated the inhibition of enzyme E at concentrations of copper sulfate solution greater than 0.03% and found that the enzyme was completely inhibited.

The student suggested the hypothesis:

concentrations of copper sulfate solution below 0.03% will continue to inhibit the enzyme.

You are required to investigate this hypothesis by carrying out a serial dilution of copper sulfate solution which reduces the concentration by ten-fold between each successive dilution.

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Fig. 1.1 shows how to make the first concentration of 0.003% copper sulfate solution.

10 cm3 of 0.03%copper sulfate

solution, C

0.003%copper sulfate

solution

................... ...................

9 cm3 ofdistilledwater, W

1 cm3 ofcopper sulfate

solution, C

Fig. 1.1

(a) (i) Complete Fig. 1.1 to show how you will make two further concentrations of copper sulfate solution. [3]

Proceed as follows:

1. Prepare the concentrations of copper sulfate solution as shown in Fig. 1.1 in the containers provided. Use the syringe labelled ‘For copper sulfate’.

2. Label test-tubes with the concentrations of copper sulfate solutions and label another test-tube W.

3. Wipe the tile clean with a damp paper towel and then dry the tile. Label the tile, as shown in Fig. 1.2. The numbers indicate the sampling times in seconds.

15 30 45 60

75 90 105 120

135 150 165 180

drop ofiodine

Fig. 1.2

4. Put one drop of iodine on the tile at each sampling time, as shown in Fig. 1.2.

5. Put 1 cm3 of W into the labelled test-tube.

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6. Put 3 cm3 of S into the same test-tube. Mix well.

7. Put 0.5 cm3 of E into the same test-tube. Mix and start timing.

8. Use a glass rod to stir the mixture.

9. After 15 seconds use the glass rod to transfer a drop of the mixture to the iodine drop, labelled 15, on the tile.

10. Immediately clean the glass rod with a paper towel.

11. Repeat steps 8 to 10 at 15 second intervals until the iodine drop does not change colour. If the iodine drop changes colour at 180 seconds, record ‘more than 180’ as your result (for step 12).

12. Record the time taken to reach the end-point.

13. Repeat steps 3 to 12 replacing the 1 cm3 of W with 1 cm3 of the lowest concentration of copper sulfate solution.

14. Repeat step 13 with the other concentrations of copper sulfate solution.

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(ii) Prepare the space below and record your results.

[5]

(iii) The student’s hypothesis stated that “concentrations of copper sulfate solution below 0.03% will continue to inhibit the enzyme”.

Explain how your results provide evidence for the support or the rejection of this hypothesis.

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(iv) Identify one significant source of error in your investigation.

.................................................................................................................................

............................................................................................................................. [1]

(v) A colorimeter could have been used to determine the end-point. Describe three other modifications to this investigation which would improve the

confidence in your results.

.................................................................................................................................

.................................................................................................................................

.................................................................................................................................

.................................................................................................................................

.................................................................................................................................

.................................................................................................................................

............................................................................................................................. [3]

Table 1.1 shows the results of an investigation into the effect of the concentration of copper sulfate solution on a protein suspension. A protein suspension was mixed with different concentrations of copper sulfate solution.

After a set time, the percentage absorbance of light was measured using a colorimeter.

Table 1.1

copper sulfate concentration

/ mol dm–3

× 10–3

absorbance of light by protein suspension / %

trial1

trial2

trial3

trial4

trial5

mean

25.0 100 99 100 99 100 100

12.5 97 95 80 97 94 96

5.5 78 81 79 82 80 80

3.5 84 59 58 58 62

1.5 9 11 10 9 8 9

(b) (i) Draw a circle around each of the anomalous results and complete the table. [2]

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(ii) Plot a graph of the data shown in Table 1.1.

[4]

(iii) Explain the effect of copper sulfate solution on the protein suspension.

.................................................................................................................................

.................................................................................................................................

.................................................................................................................................

.................................................................................................................................

............................................................................................................................. [2]

[Total: 22]

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2 J1 is a slide of a stained transverse section through a leaf.

Fig. 2.1

(a) Draw a large plan diagram of the part of the leaf indicated by the shaded area in Fig. 2.1.

Label the xylem and an air space.

[5]

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(b) Make a large drawing of six cells from the part of the leaf indicated by the shaded area in Fig. 2.2.

The cells should be two adjacent (touching) cells from the epidermis and two adjacent cells from each of the next two layers.

Fig. 2.2

Label one epidermal cell.

[5]

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Fig. 2.3 is a photomicrograph of a transverse section through a leaf of a different plant species.

Y

Fig. 2.3

(c) The actual length of line Y is 785 μm. Use this measurement to calculate the magnification of Fig. 2.3.


magnification × .................................................. [3]

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(d) Prepare the space below so that it is suitable for you to record the observable differences between the specimens on J1 and in Fig. 2.3.

Record your observations in the space you have prepared.

[5]

[Total: 18]

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BIOLOGY 9700/32


2 hours




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You are reminded that you have two hours to complete questions 1, 2 and 3.It is expected that each question will take you approximately 40 minutes.

Question 2 does not require any apparatus or the use of a microscope. You should plan your work so that you complete this question whenever you have spare time.

You may start with either Question 1 or Question 3, which require the use of apparatus or a microscope.At the start of the second hour, you should begin the work for the other question, either Question 1 or Question 3.

You should:




1 Doctors use the analysis of urine to help diagnose some medical conditions. One such medical condition is diabetes which results in glucose being released in urine if the condition is untreated.



volume/ cm3

G glucose solution none 4 30

S1 unknown glucose concentration representing urine

none – 15

S2 unknown glucose concentration representing urine

none – 15


Benedict’s solution

Benedict’s solution harmfulirritant

– 50

You are required to find the glucose concentrations of solutions S1 and S2.

You are required to carry out a serial dilution of glucose solution, G, to reduce the concentration of the glucose solution by half between each successive dilution.

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Fig. 1.1 shows how to make the first concentration of 2% glucose solution.

................... ................... ...................

20 cm3 of 4%glucose solution, G

2% glucosesolution


10 cm3 of4% glucosesolution, G

Fig. 1.1

(a) (i) Complete Fig. 1.1 to show how you will make three further concentrations of glucose solution, G. [3]

(ii) Complete Table 1.1 to show the volumes of solutions you intend to use in your investigation.

Table 1.1

solution volume/ cm3

Benedict’s

each concentration of G

S1

S2

[2]

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Proceed as follows:

1. Prepare the dilutions of G as shown in Fig. 1.1 in the containers provided.

2. Label test-tubes with the concentrations of G.

3. Label test-tubes S1 and S2.

4. Set up a water-bath and, testing each test-tube separately, test all the concentrations of G and the solutions S1 and S2 for the presence of glucose. Start timing when the test-tube is placed into the hot water-bath. If there is no colour change after 300 seconds, record ‘more than 300’ as your result (for step 5).

5. Observe the test-tube very carefully for the first sign of a colour change. This is the end-point of the reaction. As soon as you see this colour change, record the time taken for the reaction to reach the end-point.

(b) (i) State one variable, other than the volume of each solution, which needs to be kept the same in this investigation. Describe how you will keep this variable the same.

.................................................................................................................................

.................................................................................................................................

............................................................................................................................. [1]

(ii) Prepare the space below and record your results.

[4]

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(c) (i) Estimate the concentration of glucose in solutions S1 and in S2.

S1 ......................................................

S2 ...................................................... [1]

(ii) State which solution, S1 or S2, is most likely to be from an untreated diabetic.

untreated diabetic ...................................................... [1]

[Total: 12]

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2 The diameter of a tube, which carries urine in a mammal, was measured at different distances along its length. The diameter of the tube was found to vary along its length.

The results are shown in Table 2.1.

Table 2.1

distance along the tube/ cm

diameter of the tube/ mm

0.5 1.8

4.5 2.4

12.5 3.8

20.0 5.1

24.0 5.8

(a) (i) Plot a graph of the data shown in Table 2.1.

[4]

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Fig. 2.1 is a photomicrograph of the transverse section through this tube.

lumen

X

connectivetissue

muscle tissue

fold

epithelialtissue

Fig. 2.1 magnification × 22

(b) (i) Calculate the actual diameter of the tube shown by line X in Fig. 2.1.


[4]

(ii) Use the actual diameter of the tube calculated in (ii) and your graph in (a)(i) to estimate the distance along the length of the tube, where the section was cut.

................................................... [1]

(iii) Describe how you would find the mean diameter of the tube shown in Fig. 2.1.

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [2]

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Fig. 2.2 is a photomicrograph of a transverse section of a different tube from a mammal.

lumen

connectivetissue

muscletissue

epithelialtissue

magnification × 90Fig. 2.2

(iv) Prepare the space below so that it is suitable for you to record the observable differences between the specimens in Fig. 2.1 and in Fig. 2.2.


[5]

[Total: 16]

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3 L1 is a slide of a stained transverse section through a stem.

(a) (i) Draw a large plan diagram of the whole of the transverse section.

Label the epidermis and xylem.

[5]

(ii) Calculate the ratio of the total diameter of the stem to the diameter of the central pith.


[1]

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(b) (i) State one observable feature of the epidermis that supports the conclusion that this is a stem from a plant growing in a dry habitat.

Explain how this feature reduces water loss.

feature .....................................................................................................................

explanation ..............................................................................................................

.................................................................................................................................

.............................................................................................................................. [1]

(ii) Make a large drawing of three adjacent (touching) cells from the central pith.

Label the cell wall.

[5]

[Total: 12]

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BIOLOGY 9700/33


2 hours




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You should:




1 Urea reacts with water to form ammonium carbonate.

urea + water ammonium carbonate

Enzyme E catalyses this reaction.

Aqueous ammonium carbonate produces ammonium ions. This forms an alkaline solution which causes red litmus paper to turn blue. This will be used to indicate the end-point of the reaction.

Animals release urea into the soil in urine and ammonium carbonate is produced as part of the nitrogen cycle.



volume/ cm3

E urease solution irritant 10 25


U urea solution none – 25

labelled contents hazard details quantity

red litmus paper

– – total length of about 5 cm

1 strip

You are required to investigate the independent variable, enzyme E concentration on the formation of ammonium carbonate.

You are required to carry out a serial dilution of enzyme E, to reduce the concentration of the enzyme solution by half between each successive dilution.

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Fig. 1.1 shows how to make the first concentration of 5% enzyme E solution.

................... ................... ...................

20 cm3 of 10%enzyme solution, E

5% enzymesolution


10 cm3 of10% enzymesolution, E

Fig. 1.1

(a) (i) Complete Fig. 1.1 to show how you will make three further concentrations of enzyme E solution. [3]

As part of this investigation you are required to set up a suitable control.

(ii) Describe how you will set up this control using the apparatus provided.

..................................................................................................................................

.............................................................................................................................. [1]

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Proceed as follows:

1. Prepare the concentrations of E as shown in Fig. 1.1 in the containers provided.

2. Label test-tubes with the concentrations of E and the control.

3. Cut the red litmus paper into lengths of 0.5 cm. Add one piece of litmus paper to each test-tube.

4. Put 2 cm3 of U into each test-tube.

5. Put 2 cm3 of the lowest concentration of E into the labelled test-tube and mix well.

6. Repeat step 5 with each of the other concentrations of E and the control. Immediately start timing.

7. Record the time taken for the first appearance of blue colour in each piece of litmus paper. This is the end-point of the reaction.

If a piece of litmus paper does not reach the end-point in ten minutes, record ‘more than 600’ for that dilution as your result.

(iii) Prepare the space below and record your results.

[5]

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(iv) Calculate the rate of reaction for the 10% E concentration.

rate of reaction .................................................. [1]

(v) Identify one significant error in your investigation.

..................................................................................................................................

.............................................................................................................................. [1]

(vi) Suggest how you would make two improvements to this investigation.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [2]

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An investigation on global nitrogen fixation, from 1990 to 2000, studied the quantities of nitrogen fixed by different methods.

The results are shown in Table 1.1.

Table 1.1

method of fixation example of method nitrogen fixed / millions tonnes of nitrogen per

year

industrial (I) formation of nitrogen dioxide e.g. car engines

23

agricultural (A) fixation by leguminous plants e.g. peas and beans

39

depositional (D) fixation by lightning 54

natural (N) fixation in any uncultivated areas e.g. lakes, woodlands, seas

108

fertiliser production (F) production of inorganic fertilisers e.g. ammonium nitrate

77

(b) (i) Plot a chart of the data shown in Table 1.1.

[4]

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Natural fixation in the years 1840–1850 was 123 million tonnes per year. Natural fixation in the years 1990–2000 was 108 million tonnes per year.

(ii) Calculate the percentage decrease from 1840 –1850 to 1990–2000.

You may lose marks if you do not show your working.

...............................................% [2]

(iii) Suggest one reason for the difference in the natural fixation between 1840 –1850 and 1990–2000.

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [1]

[Total: 20]

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2 K1 is a slide of a stained transverse section through a leaf.

Fig. 2.1

(a) (i) Draw a large plan diagram of the part of the leaf indicated by the shaded area in Fig. 2.1.

Label the vascular bundle and the palisade layer.

[5]

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(ii) From K1, make a large drawing of one epidermal cell with one attached, whole trichome (hair).

Label the trichome (hair) and the epidermal cell.

[5]

(iii) State two observable features of K1 which support the conclusion that this is a leaf from a plant growing in a dry habitat.

Explain how these features reduce water loss.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..............................................................................................................................[2]

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Fig. 2.2 is a photomicrograph of a transverse section of a leaf from a different plant species.

Y


(b) (i) Use the magnification to calculate the actual length of line Y in μm.


.............................................μm [3]

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(ii) Prepare the space below so that it is suitable for you to record the observable similarities and differences between the specimens on K1 and in Fig. 2.2.


[5]

[Total: 20]

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BIOLOGY 9700/34


2 hours




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You should:




1 In some countries, certain plants have seasonal growth. During the summer plants transport sucrose from the leaves to store it as starch in the roots.

Table 1.1 summarises the changes in the leaves and roots during the year.

Table 1.1

season leaves roots

summer leaves synthesize sucrose sucrose stored as starch

winter no leaves starch stored

spring leaves growing starch converted to glucose

You are required to identify the source of four plant extracts. These have been taken from

• a root in winter • a root in spring • phloem sap in summer • phloem sap in winter

(a) (i) Use the information in Table 1.1 to predict which substances you would expect to be present in each of the four plant extracts, then complete Table 1.2.

Key: ✓ (tick) substance present in plant extract ✗ (cross) substance absent from plant extract

Table 1.2

source of plant extract

substances present in each of the plant extracts

starch sucrose glucose

root in winter

root in spring

phloem sap in summer

phloem sap in winter

[2]

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One sample was taken from each of the four plant extracts shown in Table 1.2.

You are required to identify from which plant extract each of the four samples S1, S2, S3 and S4 was taken.


Table 1.3

labelled contents hazard volume/ cm3

Benedict’s solution Benedict’s solution harmfulirritant

If you require more of any of these

reagents, please ask the Invigilator.

Biuret copper sulfate sodium hydroxide

harmfulirritant

iodine iodine in potassium iodide solution

irritant

hydrochloric acid hydrochloric acid irritant

sodium hydrogen carbonate

sodium hydrogen carbonate

none

(ii) Describe the tests that show that sucrose is present in a plant extract.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [2]

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Select the appropriate reagents from those provided in Table 1.3 and carry out tests to identify the samples S1, S2, S3 and S4.

(iii) Prepare the space below and record your results.

[4]

(iv) Complete Table 1.4 to match the samples, S1, S2, S3 and S4, with each plant extract.

Table 1.4

source of plant extract sample

a root in winter

a root in spring

phloem sap in summer

phloem sap in winter

[1]

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A student investigated the effect of different concentrations of sodium chloride solution on root tissues. A separate sample of root tissue was put into a starting volume of each concentration of sodium chloride solution. After a set time the root tissue was removed and the final volume of each solution was recorded. The change in volume for each concentration was calculated.

(b) (i) State three variables which the student should keep the same in this investigation. Describe how the student would keep each of these variables the same.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [4]

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The results of the student’s investigation are shown in Table 1.5.

Table 1.5

concentration of sodium chloride/ mol dm–3

change in volume of solution/ cm3

0.00 –6.0

0.25 +1.0

0.50 +4.5

0.80 +5.2

1.00 +5.2

(ii) Plot a graph of the data shown in Table 1.5.

[4]

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(iii) Show on your graph the sodium chloride concentration where there is no change in volume of solution. [1]

Use this information to estimate the sodium chloride concentration where there is no change in volume of solution.

................................... mol dm–3 [1]

(iv) Use your graph to explain the effect of the different concentrations of sodium chloride solution on the root cells.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [3]

[Total: 22]

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2 Fig. 2.1 is a photomicrograph of a transverse section through part of a stem.


(a) Draw a large plan diagram of the specimen shown in Fig. 2.1.

Label the epidermis.

[6]

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Fig. 2.2 is a photomicrograph of a transverse section through part of a different plant organ from a different plant species.

YY

Fig. 2.2

(b) (i) Prepare the space below so that it is suitable for you to record three observable differences between the specimens in Fig. 2.1 and in Fig. 2.2.


[4]

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(ii) The actual length of line Y is 495 μm. Use this measurement to calculate the magnification of Fig. 2.2.


magnification × ................................................. [4]

(c) You are provided with a sample of plant material, labelled P.

You are required to prepare a slide of the xylem vessels from this plant material.

Proceed as follows:

1. Using forceps extract long thin strands of P containing xylem vessels as shown in Fig. 2.3.

strand of xylem tissue

Fig. 2.3

2. Put the strands onto a microscope slide.

3. Add two drops of water and carefully lower a cover slip onto the strands.

4. Put the paper towel over the cover slip and gently press to separate the xylem vessels from surrounding tissue.

5. Look carefully under high power to find two xylem vessels which show different patterns of thickening in the walls.

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Make large drawings of two different patterns of thickening in the walls of the xylem vessels.

Label the part of the vessel where lignin is found.

[4]

[Total: 18]

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BIOLOGY 9700/35


2 hours




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You should:




1 When plant tissue is soaked in methylene blue the tissue is coloured blue. Ethanol affects the selective permeability of cell membranes.



volume/ cm3

E ethanol flammable 10 40


labelled contents hazard details quantity

P stained plant tissue methylene blue will stain your

skin

same cross-sectional area,

stained with methylene blue

and washed

3 pieces

If any methylene blue comes into contact with your skin wash off immediately with water.

It is recommended that you wear safety goggles/glasses.

You are required to investigate the effect of the independent variable, ethanol concentration, on samples of plant tissue which have been soaked in methylene blue.

You are required to carry out a serial dilution of ethanol, E, to reduce the concentration of the ethanol by half between each successive dilution.

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Fig. 1.1 shows how to make the first concentration of 5% ethanol.

20 cm3 of 10%ethanol, E

5%ethanol

................... ................... ...................


10 cm3 of10% ethanol, E

Fig. 1.1

(a) (i) Complete Fig. 1.1 to show how you will make three further concentrations of ethanol, E. [3]

As part of this investigation you are required to set up a suitable control.

(ii) Describe how you will set up this control using the apparatus provided.

..................................................................................................................................

.............................................................................................................................. [1]

Proceed as follows

(Always use blunt forceps when handling the plant tissue to avoid contact with the methylene blue.)

1. Prepare the concentrations of E as shown in Fig. 1.1 in the containers provided.

2. Label test-tubes with the concentrations of E and the control.

3. Put 5 cm3 of each dilution of E and the control into the labelled test-tubes.

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4. Remove the pieces of plant tissue from the container, labelled P, and place them onto a white tile.

5. Cut the ends off each piece of plant tissue.

6. Cut the plant tissue into equal lengths. These should be between 0.75 and 1 cm in length. The pieces should not get stuck to the side of the test-tube.

7. Empty the coloured water from the container, labelled P.

8. Place the samples back into the empty container, labelled P.

9. To remove excess methylene blue change the water five times, either using a syringe or by pouring off the water. Do not touch the plant tissue.

10. Remove the pieces of plant tissue from the beaker of water and place them on a paper towel to blot off excess water.

11. Add one piece of plant tissue to each test-tube and immediately start timing.

12. Observe the test-tubes after 10 minutes. You may find it helpful to mix the contents.

13. Record your observations.

(iii) Prepare the space below and record your observations.

[4]

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(iv) You used syringes to measure the volumes of the ethanol used.

State the volume of the smallest division on the syringe ..........................

State the degree of uncertainty in using the syringe to measure the volumes.

.............................................................................................................................. [1]

(v) Explain the effect of the ethanol on the plant tissue.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [3]

(vi) In step 5, the ends of the pieces of plant tissue were cut off. If the ends had not been cut off how would the results have been affected?

..................................................................................................................................

.............................................................................................................................. [1]

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A student carried out a similar investigation into the effect of pH on samples of coloured plant tissue. The samples were placed in different buffer solutions. After 10 minutes, the samples were removed. The buffer solutions were placed in a colorimeter to measure the percentage absorbances.

The results of this investigation are shown in Table 1.1.

Table 1.1

pH of buffer solutions absorbance/ %

4.0 83

6.0 39

7.3 10

7.8 38

8.5 78

(b) (i) Plot a graph of the data shown in Table 1.1.

[4]

(ii) Another sample of plant tissue was placed in a buffer solution and the absorbance was 46%. Use your graph to estimate the pH of the buffer solution at this absorbance.

..................................................................................................................................

.............................................................................................................................. [2]

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(iii) State two variables that need to be kept the same in this investigation. Describe how to keep each of these variables the same.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [3]

[Total: 22]

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2 Fig. 2.1 is a photomicrograph of a transverse section through a root.

draw thisquarter

magnification × 40

Fig. 2.1

(a) Draw a large plan diagram of the quarter shown in Fig. 2.1.

Label the xylem.

[5]

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Fig. 2.2 is a photomicrograph of a transverse section through a root of a different plant species.

620 µm

Fig. 2.2

(b) (i) Prepare the space below so that it is suitable for you to record the observable differences between the specimens in Fig. 2.1 and in Fig. 2.2.


[4]

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(ii) Use the scale bar to calculate the magnification of Fig. 2.2.


magnification × .................................................. [4]

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(c) You are provided with a sample of banana, labelled B.

Proceed as follows

1. Rub the cut end of the banana slice onto the centre of the microscope slide. Repeat until you can see an observable smear of banana tissue.

2. Add two drops of iodine onto the smear and carefully lower the cover slip onto the banana tissue in the smear.

3. Put the paper towel over the cover slip and gently press to separate the cells.

4. Look carefully under high power to find three cells with different shapes.

Make a large drawing of these three cells.

Label the cell wall and any observable internal structures of these cells.

[5]

[Total: 18]

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Fig. 2.1 Claude Nuridsany and Marie Perennou/Science Photo LibraryFig. 2.2 J.C. Revy, ISM/Science Photo Library



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DC (AC/DJ) 34054/5© UCLES 2011 [Turn over

UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONSGeneral Certificate of Education Advanced Level


Write your Centre number, candidate number and name on all the work you hand in.Write in dark blue or black ink.You may use a pencil for any diagrams, graphs, or rough working.Do not use staples, paper clips, highlighters, glue or correction fluid.DO NOT WRITE IN ANY BARCODES.

Answer all questions in Section A and one question from Section B.Circle the number of the Section B question you have answered in the grid below.


*6965272036*

BIOLOGY 9700/41

Paper 4 A2 Structured Questions May/June 2011

2 hours


Additional Materials: Answer Paper available on request.


Section A

1

2

3

4

5

6

7

8

Section B

9 or 10

Total

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Section A


1 The polar bear, Ursus maritimus, lives in the Arctic regions of the USA, Canada, Norway and Russia. Polar bears move across the Arctic ice sheet to hunt prey such as seals.

Fig. 1.1 shows a polar bear.

Fig. 1.1

The area over which the Arctic ice sheet extends varies throughout the year.

Fig. 1.2 shows the variation in the extent of the Arctic ice sheet for the months of July to November for the years 1979 and 2009.

12

July Aug Sept

month

Oct Nov

10

8

6

4

2

0

extent of Arctic icesheet / km2 × 106

Key

1979

2009

Fig. 1.2

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(a) Calculate the percentage reduction in the area over which the ice sheet extends between 1979 and 2009 for the month of September.

Give your answer to the nearest whole number.

Show your working.

answer .......................................... % [2]

(b) In 2008 the government of the USA classified U. maritimus as an endangered species because it is under threat of extinction.

Suggest what has caused U. maritimus to have become endangered.

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(c) U. maritimus is a eukaryote. Beneficial bacteria, which are prokaryotic cells, live in the gut of U. maritimus.

State three differences between the cells of U. maritimus and its gut bacteria.

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[Total: 8]

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2 When gold is associated with mineral ores such as iron sulfide, the sulfides must be oxidised to release the gold particles. Since the mid 1990s, gold has been extracted from such ores by bioleaching.

Suitable bacteria oxidise iron sulfide to soluble iron sulfate, releasing Fe3+ and SO42– ions.

The reaction releases heat energy and temperatures within a heap of ore that is being bioleached (a bioheap) can reach 70 °C or higher.

Examples of bacteria used in this bioleaching are shown in Table 2.1.

Table 2.1

example of bacterium temperature range for growth / °C activity natural

habitat

Acidithiobacillus ferrooxidans 35 – 45oxidiseiron and

sulfurcompounds

acid springs

Sulfobacillus thermosulfidooxidans

45 – 65

Sulfolobus metallicus 65 – 95

(a) With reference to Table 2.1, suggest

(i) a natural habitat for organisms such as S. thermosulfidooxidans and S. metallicus

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(ii) why all three species of bacteria, rather than just one species, are mixed with ore in a bioheap.

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(b) The rate of oxidation of the iron in iron sulfide ore was compared in the presence and absence of A. ferrooxidans at pH 2.0.


in presence ofA. ferrooxidans

in absence ofA. ferrooxidans

2.0

concentrationof Fe3+ ions/ arbitrary units

1.0

1.5

0.5

00 5 10 15 20

time / days

25

Fig. 2.1

(i) With reference to Fig. 2.1, describe the effect of A. ferrooxidans on the oxidation of the ore.

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(ii) Explain why bioleaching is now used on a large scale throughout the world.

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(c) Gold-bearing sulfide ores often contain arsenic, which is potentially toxic to the bacteria used in bioleaching. However, arsenic-resistant strains of A. ferrooxidans have been found in some mines.

The activity of two strains of the bacterium, in the presence and absence of arsenic ions, is shown in Table 2.2.

Table 2.2

oxidation rate of iron in the ore / mg dm–3 h–1

strain of A. ferrooxidans

arsenic ions absent arsenic ions present

1 16 15

2 48 47

Describe the results shown in Table 2.2 and explain the role of natural selection in the evolution of arsenic-resistant bacteria.

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3 (a) Outline the technique of in-vitro fertilisation (IVF).

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(b) For IVF to be successful, a sperm must have an undamaged plasma (cell surface) membrane, an intact acrosome (a sperm’s large lysosome) and be capable of producing ATP for movement.

One method of assessing the quality of a sample of sperm is to mix it with three chemical probes that bind to specific components of the sperm. The probes fluoresce when the sperm are examined with a microscope using ultra-violet (UV) light, allowing their uptake to be determined.

The three probes fluoresce with different colours.

• Probe 1 combines with DNA and fluoresces red, but can enter a sperm only when its plasma membrane is damaged.

• Probe 2 combines with sugars in the acrosome and fluoresces yellow, but can enter the acrosome only when the acrosome membrane is damaged.

• Probe 3 combines with mitochondria and fluoresces bright green in sperm with active mitochondria and less brightly when the mitochondria are less active.

A sample of sperm was mixed with all three probes and examined using UV light.

Complete Table 3.1 by placing ticks ( ) in the appropriate boxes to describe the appearance of sperm that would be suitable for use in IVF.

Table 3.1

appearance of sperm suitable for use in IVF

target of probe red yellow green colourless

DNA

acrosome

mitochondria

[3]

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(c) The technique of intracytoplasmic sperm injection (ICSI) involves injecting a single, chosen sperm into an oocyte. This technique is often used when standard IVF has failed.

Researchers in Hawaii think that the acrosome of the sperm should be removed before the sperm is injected into the oocyte.

Suggest one reason why it might improve the success rate of ICSI to remove the acrosome before injecting a sperm into an oocyte.

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[Total: 8]

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4 Almost 40% of adults with cystic fibrosis (CF) develop a form of diabetes known as cystic fibrosis-related diabetes (CFRD). This is thought to happen because the build-up of thick secretions in the pancreas destroys β cells.

(a) Explain how the destruction of β cells causes diabetes.

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(b) The bacterium Pseudomonas aeruginosa can cause chronic (long-lasting) lung infections. A person with CFRD is likely to have poorer lung function and a greater likelihood of having a chronic lung infection than a person who has CF but does not have CFRD.

An investigation was carried out to find out if the severity of damage to lung function in a person with CFRD is affected by

• their gender • whether or not they have a chronic P. aeruginosa infection.

The investigators measured lung function by recording the maximum volume of air that can be expelled from the lungs in the first one second of a forced expiration. This is known as FEV1. The lower the median FEV1, the poorer the lung function.

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Table 4.1 summarises the results of this investigation. All the 812 people in the study had cystic fibrosis.

Table 4.1

without chronic P. aeruginosa infection

withchronic P. aeruginosa infection

male female male female

withCFRD

without CFRD

with CFRD

without CFRD

withCFRD

without CFRD

withCRFD

without CFRD

number of people 44 110 52 93 106 166 121 120

FEV1 71.1 71.4 53.6 73.6 49.0 59.0 42.0 61.0

With reference to Table 4.1

(i) discuss whether or not there appears to be a positive correlation between having a chronic P. aeruginosa infection and having CFRD

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............................................................................................................................ [2] (ii) calculate the percentage difference between the FEV1 of males and females without

CFRD and without P. aeruginosa infection.

Show your working

answer .......................................... % [2]

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(iii) outline the conclusions that can be drawn concerning the relationship between gender and the severity of lung damage in a person with CFRD and with P. aeruginosa infection.

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(c) In a person with CF, damage to lung function and the increased likelihood of chronic infections are the result of the secretion of thick mucus.

Explain why thick mucus is secreted in the lungs of a person with CF.

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5 Both sorghum and maize are important food crops in dry regions of the world, but sorghum is able to produce higher yields than maize in very dry conditions.

This is partly because sorghum plants have a smaller leaf area than maize, and also because sorghum leaves have rows of motor cells along the midrib of the upper surface of the leaf, allowing the leaves to roll up.

(a) Explain how these two features adapt sorghum plants for growth in very dry conditions.

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(b) Sorghum is a staple food in Africa, but the major storage protein that it contains, kaffirin, is not easily digested by protease enzymes. The main cause of this is cross-linking between kaffirin molecules.

The digestibility of the protein in five varieties of sorghum was measured when raw, and

after cooking. Digestibility was measured as the percentage of the protein that would be broken down to amino acids during digestion.


HDI Macia Seredo

variety of sorghum

NK8828 Sudan

100

80

60

40

20

0

digestibility(percentage ofproteins broken

down toamino acids)

Key

raw

cooked

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With reference to Fig. 5.1

(i) compare the digestibility of raw and cooked sorghum protein

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(ii) using your knowledge of protein structure and enzyme activity, suggest reasons for the differences you have described in (i).

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6 Canavan disease is a non sex-linked inherited condition that causes progressive damage to neurones of the brain. Symptoms of the condition include a loss of motor skills and mental retardation. The symptoms appear in early infancy and many children with this condition die by the age of four years.

People with Canavan disease lack an enzyme called aspartoacylase which breaks down N-acetyl aspartate. The build up of N-acetyl aspartate can interfere with the formation of the myelin sheath, particularly in neurones of the brain.

(a) Enzymes such as aspartoacylase display specificity.

Outline what is meant by specificity of an enzyme.

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(b) Complete the genetic diagram below to show how an unaffected man and an unaffected woman could produce a child with Canavan disease.

key to symbols

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parental phenotypes unaffected man unaffected woman

parental genotypes

gametes

offspring genotypes

offspring phenotypes [3]

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(c) Explain the importance of the myelin sheath in the functioning of a neurone.

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7 (a) Complete the following passage about ATP by writing in the missing words.

All living organisms use energy. The most common immediate source of energy is

adenosine triphosphate (ATP) which is used in every cell for the movement of ions

against a concentration gradient, known as ............................................... .

ATP is known as the universal currency of energy.

ATP is a phosphorylated nucleotide which is known as a ‘high energy’ molecule. It is made

of an organic base, adenine, a 5 carbon sugar named ............................................... and

three phosphate groups. ATP is very soluble in ............................................... and easily

transported within the cell. The removal of the outer phosphate group by the process

of ............................................... releases energy. The energy released as a result of this

reaction can be channelled directly into other reactions in the cell.

A certain proportion of this energy is lost as ............................................... .

ATP is continually broken down and is reformed at a fast rate by the process of respiration.[5]

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(b) During a sporting event an athlete may have to carry out anaerobic respiration in addition to aerobic respiration to produce sufficient ATP.

Fig. 7.1 outlines both processes in a muscle cell and shows how a liver cell is linked to these processes.

Liver cell

Muscle cell

glucose

additionaloxygen

bloodlactate

bloodglucose

glucose lactate

glycolysis ATP

pyruvate

linkreaction

acetyl coA

Krebscycle

carbondioxide oxidative

phosphorylation

ATP water

Fig. 7.1

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You may refer to Fig. 7.1 in answering questions (i) to (v) below.

(i) Glucose produced in the liver cell can be released into the blood to maintain blood glucose concentration.

State one use of glucose within the liver cell.

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(ii) Suggest why anaerobic respiration is said to be less efficient than aerobic respiration.

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(iii) Complete the table to indicate, within the muscle cell, the precise locations of glycolysis, the link reaction, the Krebs cycle and oxidative phosphorylation.

process precise location

glycolysis

link reaction

Krebs cycle

oxidative phosphorylation

[4]

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(iv) Glucose is phosphorylated at the start of glycolysis in the muscle cell.

Suggest why this phosphorylated glucose does not diffuse out of the cell into the surrounding tissue fluid.

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(v) Additional oxygen is required in the metabolic pathways involved in the conversion of lactate to glucose.

State the term given to this additional oxygen.

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[Total: 15]

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8 The hedgehog, Erinaceus europaeus, is a small carnivorous mammal native to Northern Europe.

Fig. 8.1 shows a hedgehog.

Fig. 8.1

Hedgehogs were introduced onto a small group of islands off the west coast of Scotland in 1974. The hedgehog population has increased so that there are now over 5 000 breeding pairs. These hedgehogs have no natural predators on these islands and their diet consists mainly of bird’s eggs.

Fig. 8.2 shows the hedgehog population density in the year 2000.

north island

south island

10 km

Keyhigh / mediumdensity

low density

absent

Fig. 8.2

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Table 8.1 shows the changes in the populations of the species of birds from 1983 to 2000.

Table 8.1

breeding pairs in 1983

breeding pairs in 2000

% change in population

north island

oystercatcher 928 1122 +21

lapwing 1104 1364 +24

redshank 486 733 +51

south island

oystercatcher 907 1403 +55

lapwing 1869 1287 –31

redshank 1288 760 –41

(a) Using Fig. 8.2 and Table 8.1, describe the relationship between the hedgehog population density and the changes in the populations of lapwings and redshanks.

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(b) Suggest an explanation for the increase in the oystercatcher population on the south island, despite the increase in the hedgehog population.

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(c) Explain why the population of hedgehogs on one of these islands may eventually become a different species from that on mainland Scotland.

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[Total: 9]

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Section B

Answer one question.

9 (a) Outline the ways in which the endocrine and nervous systems carry out their roles in control and coordination in animals. [8]

(b) Describe the part played by auxins in apical dominance in a plant shoot. [7]

[Total: 15]

10 (a) Describe how non-cyclic photophosphorylation produces ATP and reduced NADP. [9]

(b) Outline the steps of the Calvin cycle. [6]

[Total: 15]

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Fig. 1.1 Stephen J. Krasemann/Science Photo Library.Fig. 8.1 Ian Gowland/Science Photo Library.



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DC (NH/JG) 50624/6 R© UCLES 2011 [Turn over



Write your Centre number, candidate number and name in the spaces provided at the top of this page.Write in dark blue or black ink.Do not use staples, paper clips, highlighters, glue or correction fluid.DO NOT WRITE IN ANY BARCODES.

Section AAnswer all questions.

Section BAnswer one questionCircle the number of the Section B question you have answered in the grid below.


*4665788750*

BIOLOGY 9700/42


2 hours




Section A

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Section A


1 The natterjack toad, Bufo calamita, is an endangered amphibian species in the UK. It comes out of hibernation in April and breeds in pools by sand dunes along parts of the UK coast. A young natterjack toad will take about 10 weeks to develop from a fertilised egg. A natterjack toad feeds at night, by running at its prey, mainly insects and worms, on the sand dunes.

Fig. 1.1 shows a natterjack toad.

Fig. 1.1

(a) Suggest what may have caused the natterjack toad to become an endangered species in the UK.

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(b) Fig. 1.2 shows the number of adult natterjack toads counted from 1989 to 1997 in one area of the UK.

1989 1990 1991 1992 1993 1994 1995 1996 19970

100

200

300

400

500

600

700

800

900

year

numberof

toads

Fig. 1.2

Calculate the mean annual number of adult natterjack toads counted from 1989 to 1997.


Show your working.

answer ................................................. [2]

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(c) The natterjack toad is heterotrophic.

(i) Explain what is meant by heterotrophic.

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(ii) Name two kingdoms that are exclusively heterotrophic.

1. ...............................................................................................................................

2. ........................................................................................................................... [1]

(d) Each year the International Union for the Conservation of Nature and Natural Resources (IUCN) publishes a list of endangered species called the Red List. The Red List has a very high proportion of vertebrates compared to invertebrates.

Suggest one reason why the Red List has many more vertebrates than invertebrates.

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[Total: 9]

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2 (a) Outline how an enzyme can be immobilised in alginate.

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(b) State two advantages, other than stability, of using an immobilised enzyme in an industrial process compared with the same enzyme that has not been immobilised.

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(c) Papain is a protease enzyme. Its activity at different temperatures, when immobilised onto an inert support, was compared with its activity in solution.


0

20

40

60

80

100

0 10 20 30 40 50 60 70 80

papainin

solution

temperature / °C

immobilisedpapain

activity/ arbitrary

units

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With reference to Fig. 2.1, describe and explain the differences in activity of immobilised papain and papain in solution.

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3 (a) Fig. 3.1 shows a drawing of a section through an ovarian follicle.

A

B

CD

Fig. 3.1

State the names of the parts labelled A-D in Fig. 3.1.

A .......................................................

B .......................................................

C .......................................................

D ....................................................... [4]

(b) Outline the biological basis of the effect of the oestrogen/progesterone contraceptive pill.

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(c) The zona pellucida of an oocyte is made up of ZP proteins. ZP3, which does not occur anywhere else in the body, has a complex tertiary structure and acts as a receptor for sperm during fertilisation.

A new method of contraception, which does not involve the use of hormones, is in the early stages of development. It involves blocking the expression of the gene coding for ZP3.

(i) Explain how blocking the expression of the gene coding for ZP3 acts as a contraceptive.

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(ii) Explain why it is desirable to devise a method of contraception that does not involve oestrogen and progesterone.

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(iii) Explain why it is important, when blocking the expression of the gene coding for ZP3, that ZP3 is only found in the zona pellucida.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [2]

[Total: 15]

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4 Maize, Zea mays, is a major cereal food crop. Unlike most crop plants, maize seed is produced by hybridisation between two different inbred parental strains.

(a) (i) Explain why this is done.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [3]

(ii) Suggest one disadvantage of producing seed in this way.

..................................................................................................................................

.............................................................................................................................. [1]

(b) In the light-independent stage of photosynthesis, the enzyme rubisco catalyses the combination of carbon dioxide with ribulose bisphosphate, RuBP. When the carbon dioxide concentration within the leaf is very low, rubisco tends to combine oxygen, rather than carbon dioxide, with RuBP. This process is called photorespiration. It reduces carbon dioxide assimilation and therefore reduces crop yields.

Photorespiration is most likely to happen in hot, dry conditions.

(i) Suggest why photorespiration is most likely to take place in hot, dry conditions.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [3]

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(ii) Explain how the leaf anatomy of a maize plant reduces photorespiration, even in hot, dry conditions.

..................................................................................................................................

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..................................................................................................................................

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(c) It is expected that the carbon dioxide concentration in the atmosphere will increase in the future, which would be expected to increase rates of photosynthesis in many crop plants.

Investigations were carried out into the effect of increased carbon dioxide concentration on the rate of photosynthesis in maize.

• Maize plants were grown in open-air trials, in the same field and were exposed to the same changes in the weather.

• 50% of the plants were exposed to a normal carbon dioxide concentration. • 50% of the plants were exposed to an increased carbon dioxide concentration. • The rate of photosynthesis was measured as the net assimilation rate of

carbon dioxide. • Measurements were made at three-hourly intervals between 0700 hours and

1900 hours on three different days.


6 day 1 day 2 day 3

4

2

0

0700

1000

1300

1600

1900

6

4

2

0

net assimilationrate of CO2

/ arbitrary units

0700

1000

1300

1600

1900

6

4

2

0

0700

1000

1300

1600

1900

time of day

normal CO2 concentration

increased CO2 concentration

key

Fig. 4.1

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(i) Suggest an explanation for the lack of effect of carbon dioxide concentration on the rate of photosynthesis in maize plants, shown by these results.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [2]

(ii) Suggest one explanation for the changes in the rate of photosynthesis between 0700 hours and 1900 hours on day 1.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [2]

[Total: 15]

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5 In the USA, about 35% of all maize that is grown has been genetically modified to produce a toxin, called Bt toxin, derived from the bacterium Bacillus thuringiensis. The genetically modified plants are known as Bt maize.

(a) Explain the advantages of growing Bt maize.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [2]

(b) An investigation was carried out into the potential effects of dead leaves from Bt maize on organisms living in streams that flow through areas where the maize is grown.

The researchers conducted a laboratory-based experiment in which larvae of one species of aquatic caddis fly, Lepidostoma liba, were fed on non-Bt maize leaves, or on leaves from Bt maize. The growth rates of the larvae were measured.

The results are summarised in Fig. 5.1.

0.0

0.5

1.0

non-Bt maize Bt maize

mean growthrate / arbitraryunits

Fig. 5.1

Describe the effect of eating leaves from Bt maize on the growth rate of L. liba larvae.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [2]

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(c) In a second laboratory-based experiment, three groups of larvae of a different species of caddis fly, Helicopsyche borealis, were fed on pollen containing:

A no Bt toxin

B Bt toxin at concentrations found in streams in maize-growing areas

C Bt toxin at concentrations twice as high as found in those streams.

The researchers measured the mortality rates of the caddis fly larvae.

Their results are summarised in Table 5.1.

Table 5.1

groups compared difference in mortality rate

groups A and B no significant difference

groups A and C significantly greater mortality in C than in A

The researchers were careful to state that their results showed the ‘potential ecological effects’ on the caddis fly larvae of growing Bt maize.

Suggest two reasons why ‘potential ecological effects’ is a suitable description of any conclusions that could be drawn from the results of this experiment.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [2]

(d) When the results of the experiments described in (b) and (c) were published, many other scientists criticised the research very strongly.

Suggest why some scientists might wish to suppress results such as these, even if there is no fault with the investigation itself.

..........................................................................................................................................

...................................................................................................................................... [1]

[Total: 7]

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6 The Krebs cycle occurs in the matrix of the mitochondrion.

Fig. 6.1 outlines the steps of the Krebs cycle.

acetyl CoA( 2C )

CO2

CO2

2H

2HK

K

32

1

4

5

6

7

intermediates( 5C )

K

reducedFAD

ATP

2H

2Hcitrate( 6C )

L ( 4C )

Fig. 6.1

(a) With reference to Fig. 6.1 name the process occurring at:

(i) 1 and 3 ................................................................................................ [1]

(ii) 2, 4, 6 and 7 ............................................................................................... [1]

(iii) 5 ............................................................................................... [1]

(b) Name the compounds K and L.

K .......................................................................................................................................

L.................................................................................................................................... [2]

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(c) Most of the hydrogen atoms that are released by the Krebs cycle will take part in oxidative phosphorylation on the cristae of the mitochondria.

Outline the process of oxidative phosphorylation.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [5]

[Total: 10]

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7 Meiosis is a type of nuclear division, which produces gametes for sexual reproduction.

(a) Fig. 7.1 shows diagrams of the stages of meiosis, A to J, but they are not in the correct order.

A B C

D E F

G H I J

Fig. 7.1

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Complete the table below by writing the stages of meiosis in the correct order.

Some of the stages have already been written in the table.

nuclear division letter of stage

meiosis I

B

D

meiosis II

[4]

(b) Explain how meiosis can result in genetic variation amongst offspring.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [5]

[Total: 9]

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8 The following passage is a summary of the main principles of natural selection.

Some of the words have been omitted.

Write the most appropriate term in each space.

Individuals in a population have great ......................................................... potential and yet

the numbers in a population remain roughly ......................................................... . This is

because many die due to environmental factors and therefore do not reproduce. There is

......................................................... amongst members of a population and those with

the features best adapted to the environment survive. They reproduce and pass on their

......................................................... to their offspring. This may lead to a change in the

......................................................... pool of the population and over time may lead to

evolutionary change. [5]

[Total: 5]

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9 Huntington’s Disease (HD) is a severe neurological disorder in which symptoms usually appear after the person has reached sexual maturity. Symptoms include memory loss and changes in personality and mood.

HD is caused by a gene mutation on chromosome 4 in which the triplet code CAG is repeated many times. The resulting allele is dominant.

(a) Explain what is meant by the terms gene mutation and triplet code.

gene mutation ...................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

triplet code ........................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [4]

(b) A couple wish to start a family. The man does not have HD but the woman does have the disease. The woman’s father does not have the disease.

Complete the genetic diagram below to show the probability of the couple’s first child having HD.

key Huntington allele = T normal allele = t

parental phenotypes man without HD woman with HD

parental genotypes ............................ ............................

gametes .......................................... .........................................

offspring genotypes ........................................................................................

offspring phenotypes ........................................................................................

probability of first child having HD ............................................................................ [3]

[Total: 7]

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Section B


10 (a) Describe the photoactivation of chlorophyll and its role in cyclic photophosphorylation. [8]

(b) Explain briefly how reduced NADP is formed in the light-dependent stage and how it is used in the light-independent stage. [7]

[Total: 15]

11 (a) Describe the role of abscisic acid (ABA) in the closure of a stoma. [8]

(b) Describe the role of gibberellins in the germination of barley seeds. [7]

[Total: 15]

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Question 1 © Stephen Dalton; www.nhpa.co.uk



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DC (NH/JG) 50625/6 R© UCLES 2011 [Turn over



Write your Centre number, candidate number and name in the spaces provided at the top of this page.Write in dark blue or black ink.Do not use staples, paper clips, highlighters, glue or correction fluid.DO NOT WRITE IN ANY BARCODES.

Section AAnswer all questions.

Section BAnswer one questionCircle the number of the Section B question you have answered in the grid below.


*8742173785*

BIOLOGY 9700/43


2 hours




Section A

1

2

3

4

5

6

7

8

9

Section B

10 or 11

Total

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Section A


1 The natterjack toad, Bufo calamita, is an endangered amphibian species in the UK. It comes out of hibernation in April and breeds in pools by sand dunes along parts of the UK coast. A young natterjack toad will take about 10 weeks to develop from a fertilised egg. A natterjack toad feeds at night, by running at its prey, mainly insects and worms, on the sand dunes.

Fig. 1.1 shows a natterjack toad.

Fig. 1.1

(a) Suggest what may have caused the natterjack toad to become an endangered species in the UK.

..........................................................................................................................................

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..........................................................................................................................................

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..........................................................................................................................................

...................................................................................................................................... [3]

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(b) Fig. 1.2 shows the number of adult natterjack toads counted from 1989 to 1997 in one area of the UK.

1989 1990 1991 1992 1993 1994 1995 1996 19970

100

200

300

400

500

600

700

800

900

year

numberof

toads

Fig. 1.2

Calculate the mean annual number of adult natterjack toads counted from 1989 to 1997.


Show your working.

answer ................................................. [2]

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(c) The natterjack toad is heterotrophic.

(i) Explain what is meant by heterotrophic.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [2]

(ii) Name two kingdoms that are exclusively heterotrophic.

1. ...............................................................................................................................

2. ........................................................................................................................... [1]

(d) Each year the International Union for the Conservation of Nature and Natural Resources (IUCN) publishes a list of endangered species called the Red List. The Red List has a very high proportion of vertebrates compared to invertebrates.

Suggest one reason why the Red List has many more vertebrates than invertebrates.

..........................................................................................................................................

...................................................................................................................................... [1]

[Total: 9]

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2 (a) Outline how an enzyme can be immobilised in alginate.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [2]

(b) State two advantages, other than stability, of using an immobilised enzyme in an industrial process compared with the same enzyme that has not been immobilised.

1. ......................................................................................................................................

..........................................................................................................................................

2. ......................................................................................................................................

...................................................................................................................................... [2]

(c) Papain is a protease enzyme. Its activity at different temperatures, when immobilised onto an inert support, was compared with its activity in solution.


0

20

40

60

80

100

0 10 20 30 40 50 60 70 80

papainin

solution

temperature / °C

immobilisedpapain

activity/ arbitrary

units

Fig. 2.1

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With reference to Fig. 2.1, describe and explain the differences in activity of immobilised papain and papain in solution.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

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...................................................................................................................................... [4]

[Total: 8]

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3 (a) Fig. 3.1 shows a drawing of a section through an ovarian follicle.

A

B

CD

Fig. 3.1

State the names of the parts labelled A-D in Fig. 3.1.

A .......................................................

B .......................................................

C .......................................................

D ....................................................... [4]

(b) Outline the biological basis of the effect of the oestrogen/progesterone contraceptive pill.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

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..........................................................................................................................................

...................................................................................................................................... [4]

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(c) The zona pellucida of an oocyte is made up of ZP proteins. ZP3, which does not occur anywhere else in the body, has a complex tertiary structure and acts as a receptor for sperm during fertilisation.

A new method of contraception, which does not involve the use of hormones, is in the early stages of development. It involves blocking the expression of the gene coding for ZP3.

(i) Explain how blocking the expression of the gene coding for ZP3 acts as a contraceptive.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [3]

(ii) Explain why it is desirable to devise a method of contraception that does not involve oestrogen and progesterone.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [2]

(iii) Explain why it is important, when blocking the expression of the gene coding for ZP3, that ZP3 is only found in the zona pellucida.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [2]

[Total: 15]

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4 Maize, Zea mays, is a major cereal food crop. Unlike most crop plants, maize seed is produced by hybridisation between two different inbred parental strains.

(a) (i) Explain why this is done.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [3]

(ii) Suggest one disadvantage of producing seed in this way.

..................................................................................................................................

.............................................................................................................................. [1]

(b) In the light-independent stage of photosynthesis, the enzyme rubisco catalyses the combination of carbon dioxide with ribulose bisphosphate, RuBP. When the carbon dioxide concentration within the leaf is very low, rubisco tends to combine oxygen, rather than carbon dioxide, with RuBP. This process is called photorespiration. It reduces carbon dioxide assimilation and therefore reduces crop yields.

Photorespiration is most likely to happen in hot, dry conditions.

(i) Suggest why photorespiration is most likely to take place in hot, dry conditions.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [3]

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(ii) Explain how the leaf anatomy of a maize plant reduces photorespiration, even in hot, dry conditions.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [4]

(c) It is expected that the carbon dioxide concentration in the atmosphere will increase in the future, which would be expected to increase rates of photosynthesis in many crop plants.

Investigations were carried out into the effect of increased carbon dioxide concentration on the rate of photosynthesis in maize.

• Maize plants were grown in open-air trials, in the same field and were exposed to the same changes in the weather.

• 50% of the plants were exposed to a normal carbon dioxide concentration. • 50% of the plants were exposed to an increased carbon dioxide concentration. • The rate of photosynthesis was measured as the net assimilation rate of

carbon dioxide. • Measurements were made at three-hourly intervals between 0700 hours and

1900 hours on three different days.


6 day 1 day 2 day 3

4

2

0

0700

1000

1300

1600

1900

6

4

2

0

net assimilationrate of CO2

/ arbitrary units

0700

1000

1300

1600

1900

6

4

2

0

0700

1000

1300

1600

1900

time of day

normal CO2 concentration

increased CO2 concentration

key

Fig. 4.1

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(i) Suggest an explanation for the lack of effect of carbon dioxide concentration on the rate of photosynthesis in maize plants, shown by these results.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [2]

(ii) Suggest one explanation for the changes in the rate of photosynthesis between 0700 hours and 1900 hours on day 1.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [2]

[Total: 15]

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Use

5 In the USA, about 35% of all maize that is grown has been genetically modified to produce a toxin, called Bt toxin, derived from the bacterium Bacillus thuringiensis. The genetically modified plants are known as Bt maize.

(a) Explain the advantages of growing Bt maize.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [2]

(b) An investigation was carried out into the potential effects of dead leaves from Bt maize on organisms living in streams that flow through areas where the maize is grown.

The researchers conducted a laboratory-based experiment in which larvae of one species of aquatic caddis fly, Lepidostoma liba, were fed on non-Bt maize leaves, or on leaves from Bt maize. The growth rates of the larvae were measured.

The results are summarised in Fig. 5.1.

0.0

0.5

1.0

non-Bt maize Bt maize

mean growthrate / arbitraryunits

Fig. 5.1

Describe the effect of eating leaves from Bt maize on the growth rate of L. liba larvae.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [2]

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(c) In a second laboratory-based experiment, three groups of larvae of a different species of caddis fly, Helicopsyche borealis, were fed on pollen containing:

A no Bt toxin

B Bt toxin at concentrations found in streams in maize-growing areas

C Bt toxin at concentrations twice as high as found in those streams.

The researchers measured the mortality rates of the caddis fly larvae.

Their results are summarised in Table 5.1.

Table 5.1

groups compared difference in mortality rate

groups A and B no significant difference

groups A and C significantly greater mortality in C than in A

The researchers were careful to state that their results showed the ‘potential ecological effects’ on the caddis fly larvae of growing Bt maize.

Suggest two reasons why ‘potential ecological effects’ is a suitable description of any conclusions that could be drawn from the results of this experiment.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [2]

(d) When the results of the experiments described in (b) and (c) were published, many other scientists criticised the research very strongly.

Suggest why some scientists might wish to suppress results such as these, even if there is no fault with the investigation itself.

..........................................................................................................................................

...................................................................................................................................... [1]

[Total: 7]

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Use

6 The Krebs cycle occurs in the matrix of the mitochondrion.

Fig. 6.1 outlines the steps of the Krebs cycle.

acetyl CoA( 2C )

CO2

CO2

2H

2HK

K

32

1

4

5

6

7

intermediates( 5C )

K

reducedFAD

ATP

2H

2Hcitrate( 6C )

L ( 4C )

Fig. 6.1

(a) With reference to Fig. 6.1 name the process occurring at:

(i) 1 and 3 ................................................................................................ [1]

(ii) 2, 4, 6 and 7 ............................................................................................... [1]

(iii) 5 ............................................................................................... [1]

(b) Name the compounds K and L.

K .......................................................................................................................................

L.................................................................................................................................... [2]

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(c) Most of the hydrogen atoms that are released by the Krebs cycle will take part in oxidative phosphorylation on the cristae of the mitochondria.

Outline the process of oxidative phosphorylation.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [5]

[Total: 10]

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7 Meiosis is a type of nuclear division, which produces gametes for sexual reproduction.

(a) Fig. 7.1 shows diagrams of the stages of meiosis, A to J, but they are not in the correct order.

A B C

D E F

G H I J

Fig. 7.1

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Complete the table below by writing the stages of meiosis in the correct order.

Some of the stages have already been written in the table.

nuclear division letter of stage

meiosis I

B

D

meiosis II

[4]

(b) Explain how meiosis can result in genetic variation amongst offspring.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [5]

[Total: 9]

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8 The following passage is a summary of the main principles of natural selection.

Some of the words have been omitted.

Write the most appropriate term in each space.

Individuals in a population have great ......................................................... potential and yet

the numbers in a population remain roughly ......................................................... . This is

because many die due to environmental factors and therefore do not reproduce. There is

......................................................... amongst members of a population and those with

the features best adapted to the environment survive. They reproduce and pass on their

......................................................... to their offspring. This may lead to a change in the

......................................................... pool of the population and over time may lead to

evolutionary change. [5]

[Total: 5]

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9 Huntington’s Disease (HD) is a severe neurological disorder in which symptoms usually appear after the person has reached sexual maturity. Symptoms include memory loss and changes in personality and mood.

HD is caused by a gene mutation on chromosome 4 in which the triplet code CAG is repeated many times. The resulting allele is dominant.

(a) Explain what is meant by the terms gene mutation and triplet code.

gene mutation ...................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

triplet code ........................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [4]

(b) A couple wish to start a family. The man does not have HD but the woman does have the disease. The woman’s father does not have the disease.

Complete the genetic diagram below to show the probability of the couple’s first child having HD.

key Huntington allele = T normal allele = t

parental phenotypes man without HD woman with HD

parental genotypes ............................ ............................

gametes .......................................... .........................................

offspring genotypes ........................................................................................

offspring phenotypes ........................................................................................

probability of first child having HD ............................................................................ [3]

[Total: 7]

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© UCLES 2011 9700/43/M/J/11

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Section B


10 (a) Describe the photoactivation of chlorophyll and its role in cyclic photophosphorylation. [8]

(b) Explain briefly how reduced NADP is formed in the light-dependent stage and how it is used in the light-independent stage. [7]

[Total: 15]

11 (a) Describe the role of abscisic acid (ABA) in the closure of a stoma. [8]

(b) Describe the role of gibberellins in the germination of barley seeds. [7]

[Total: 15]

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Question 1 © Stephen Dalton; www.nhpa.co.uk



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DC (SJF/DJ) 34867/6© UCLES 2011 [Turn over



Write your Centre number, candidate number and name on all the work you hand in.Write in dark blue or black ink.You may use a soft pencil for any diagrams, graphs or rough working.Do not use staples, paper clips, highlighters, glue or correction fluid.DO NOT WRITE IN ANY BARCODES.

Answer both questions.


*8814460582*

BIOLOGY 9700/51

Paper 5 Planning, Analysis and Evaluation May/June 2011

1 hour 15 minutes




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1 A student investigated the storage tissue in potato tubers of different ages

• a newly formed tuber

• an old tuber that was just beginning to form new shoots.

In one investigation, the water potential of different parts of the tubers was estimated using discs of potato tissue and sucrose solutions of different concentrations.

Fig. 1.1 shows

• the appearance of the tubers

• the places from where the tissues were removed.

tissue taken from theinside of the tubernext to a bud

bud

tuber tissue taken fromthe inside of the

centre of the tuber

newly formed tuber old tuber developingnew shoots

leaves

shoot new shoots

tissue taken from theinside of the tuber

next to a new shoot

tuber

Fig. 1.1

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The results of the investigation are shown in Fig. 1.2.

4

3

2

1

00 0.0 0 20.2 0 40.4 0 80.8 1 01.0 0 0 2 0 4 0 8 1 0

percentagechange in mass

–1

–2

–3

–4

0 60.60 6

old tuberKey

near new shoot central region

newly formed tuber near bud central region

concentration of sucrose solution / mol dm–3

Fig. 1.2

(a) Describe a procedure by which the student could have obtained the results in Fig. 1.2.

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...................................................................................................................................... [8]

(b) (i) State how the percentage change in mass is calculated.

..................................................................................................................................

.............................................................................................................................. [1]

(ii) Explain why the student used percentage change in mass rather than actual mass.

..................................................................................................................................

.............................................................................................................................. [1]

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Fig. 1.3 shows the same data as Fig. 1.2.

4

3

2

1

00.0.0 0 20.2 0 40.4 0 80.8 1 01.0.0 0 2 0 4 0 8 1 0

percentagechange in mass

–1

–2

–3

–4

0.60.60.6

old tuberKey

near new shoot central region

newly formed tuber near bud central region


Fig. 1.3

The student looked at the graphs in Fig. 1.3 and estimated the water potential from where there was no change in mass.

The student decided to find out if the difference in the water potential between the central region of the old tuber and the central region of the newly formed tuber was significant.

• 20 samples of tissue were taken from the central region of each tuber.

• The change in mass was measured separately for each sample using the same procedure as in the original investigation.

(c) (i) Give one reason why the t -test is a suitable statistical test for this investigation.

..................................................................................................................................

.............................................................................................................................. [1]

(ii) Explain how the student should use the value for t to find out if the difference in water potential between the tubers is significant.

..................................................................................................................................

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..................................................................................................................................

.............................................................................................................................. [2]

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From the readings in Fig. 1.3 the student concluded that

• the tissue in the old tuber close to the growing shoot has the lowest water potential.

• in the old tuber close to a growing shoot, starch reserves were being converted to sugar.

• in the old tuber central region, starch was being converted to sugar.

• in the newly formed tuber all the sugar had been converted to starch.

(d) With reference to Fig. 1.3, state the evidence that supports these conclusions and the evidence that does not support these conclusions.

evidence to support these conclusions

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

evidence that does not support these conclusions

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

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...................................................................................................................................... [3]

(e) Suggest what further investigations the student could do to provide more support for the conclusions about starch and sugar in the storage tissue.

..........................................................................................................................................

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...................................................................................................................................... [2]

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(f) The student found that newly formed tubers do not form shoots until a period of dormancy lasting several months has occurred.

The student investigated tissues taken from tubers of different ages to test the hypothesis

Dormancy in tubers is caused by an inhibitory growth regulator.

Suggest what results would be obtained if this hypothesis was valid.

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [2]

[Total: 20]

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2 Organo-mercury compounds are toxic. They are used as pesticides, as preservatives for vaccines and as surface antiseptics.

The effects of an organo-mercury compound on mitosis were investigated in a cell culture of human white blood cells. The cells were exposed to different concentrations of the compound for one hour.

Observations of the chromosomes in these cells were made using a light microscope at × 400 magnification. Two types of abnormal mitosis were seen.

Type 1 the chromosomes were clumped close together in the middle of the cell.

Type 2 the spindle had not formed in the cell.

The frequency of each type of abnormality was obtained by observing 100 cells.

Table 2.1 shows the results.

Table 2.1

concentration of organo-mercury compound / µmol dm–3

frequency of the type of mitosis observed

Type 1 Type 2 Normal

0 0 18 82

2 0 19 81

10 0 38 62

20 1 44 55

50 16 50 34

100 55 28 17

200 89 11 0

(a) Outline how the white blood cells may have been treated so that the chromosomes could be observed.

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...................................................................................................................................... [2]

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(b) (i) Identify the independent and dependent variables in the investigation.

independent .............................................................................................................

dependent ............................................................................................................ [2]

(ii) Identify the control for this investigation.

.............................................................................................................................. [1]

(iii) Use the grid and the data in Table 2.1 to plot a line graph showing the frequency of normal mitosis at each concentration of the organo-mercury compound.

[3]

(c) (i) Suggest an explanation for the effect of organo-mercury compounds on mitosis.

.................................................................................................................................

............................................................................................................................. [1]

(ii) The data in this investigation was considered to be reliable.

Suggest one reason why this is so.

..................................................................................................................................

.............................................................................................................................. [1]

[Total: 10]

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DC (SJF/DJ) 34868/6© UCLES 2011 [Turn over






*4956470491*

BIOLOGY 9700/52


1 hour 15 minutes




1

2

Total

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ForExaminer’s

Use

1 A student used the procedure outlined below to find the water potential of a plant storage tissue that has coloured cell sap.

• pieces of plant tissue are placed into different sucrose solutions of known concentrations to allow osmosis to occur

• damaged cells release pigment that colours the sucrose solutions that bathe the tissue

• the water potential of the sucrose solutions may change as a result of osmosis

• sucrose solutions become less dense if they gain water from the tissue

• a pipette is filled with the coloured sucrose solution that has bathed the plant tissue

• a drop of the coloured bathing sucrose solution is released half way down a tube of sucrose solution of the same concentration as the original bathing solution as shown in Fig. 1.1

• the direction and rate of movement of the drop of coloured solution is determined by its density

coloured sucrosesolution collectedin pipette

sucrose solution ofsame concentrationas original bathingsolution

released droplet

coloured bathingsucrose solution

Fig. 1.1

Fig. 1.2 shows the results that the student plotted from the investigation.

0.0.0 0 20.2 0 40.4 0 80.8 1 01.0.00.0

1.0

2.0

3.0

4.0

–1.0

–2.0

–3.0

–4.0

0 2 0 4 0 8 1 0

rate ofmovementof released droplet

0.60.60.6


Fig. 1.2

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ForExaminer’s

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(a) Describe how the student could use this procedure to find the water potential of the plant storage tissue that has coloured cell sap.

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...................................................................................................................................... [8]

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(b) (i) Suggest suitable units for the rate of movement of the drop.

.............................................................................................................................. [1]

(ii) State how the student would estimate the water potential of the plant tissue.

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [2]

(c) (i) Identify the independent and dependent variables in this investigation.

independent .............................................................................................................

..................................................................................................................................

dependent ................................................................................................................

.............................................................................................................................. [2]

(ii) Identify two variables which the student may not have adequately controlled during the investigation.

1. ...............................................................................................................................

2. ........................................................................................................................... [2]

(iii) State how one of the variables you have identified in (c)(ii) may have influenced the results.

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [1]

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ForExaminer’s

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(d) The student made direct observations of the cells of the tissues that had been immersed in 0.2 mol dm–3 and 0.8 mol dm–3 sucrose solutions.

(i) Predict the appearance of the cells under the microscope when immersed in

0.2 mol dm–3 sucrose solution ...................................................................................

..................................................................................................................................


.............................................................................................................................. [1]

Use the space below for any diagrams you include in your answer to (i).

(ii) Explain your answers to (d)(i).

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [2]

[Total: 19]

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ForExaminer’s

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2 One possible cause of infertility in women is the failure of immature oocytes to complete meiosis. Scientists studying the causes of infertility tested a naturally occurring compound, FF-MAS, to find out how it stimulates meiosis to restart in oocytes.

One hypothesis is that FF-MAS activates a specific membrane receptor, LXR alpha. This hypothesis was tested on mice using FF-MAS and three compounds known to activate this receptor in other cells.

The main stages of the experimental procedure were

• immature female mice were injected with follicle stimulating hormone (FSH) and their ovaries removed 48 hours later

• the oocytes were isolated and cultured in a medium that maintains them at the primary oocyte stage of development

• different concentrations of the test compounds were added to separate cultures of oocytes

• the whole procedure was repeated for each compound

• the effect of each test compound on meiosis was recorded after 24 hours

• the mean percentage of cells showing stimulation of meiosis was calculated together with the standard error (SM)

Table 2.1 shows the results of this investigation.

Table 2.1

mean percentage stimulation of meiosis ± SM

compoundconcentration of the activator compound added to the oocytes / μmol dm–3

0.00 0.07 0.70 7.00

FF-MAS 11.9 ± 2.6 11.5 ± 3.2 39.0 ± 5.6 86.1 ± 1.7

cholesterol 9.6 ± 1.6 13.8 ± 2.9 12.5 ± 2.7 15.5 ± 2.7

22R-HC 10.5 ± 1.3 14.7 ± 6.2 15.8 ± 1.6 6.0 ± 1.2

25-HC 15.1 ± 2.6 15.0 ± 2.2 9.8 ± 0.3 14.1 ± 1.7

(a) (i) Suggest why the mice were treated with FSH before the ovaries were removed.

..................................................................................................................................

.............................................................................................................................. [1]

(ii) Suggest the purpose of keeping the oocytes in a medium that maintains them at the primary oocyte stage.

..................................................................................................................................

.............................................................................................................................. [1]

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(b) Explain what SM shows about the mean percentage values.

..........................................................................................................................................

...................................................................................................................................... [1]

Statistical tests were carried out to compare the stimulatory effects on meiosis of FF-MAS with the effects of the other compounds at each of the three concentrations used.

(c) (i) State the null hypothesis for these tests.

..................................................................................................................................

.............................................................................................................................. [1]

(ii) State a statistical test that could be used and give the reason for your choice.

test ...........................................................................................................................

reason for your choice ..............................................................................................

.............................................................................................................................. [2]

(iii) The result of the statistical test comparing FF-MAS with 22R-HC at 0.70 μmol dm–3 was significant at 0.05 probability level. Explain what this means.

..................................................................................................................................

.............................................................................................................................. [1]

(d) (i) State whether or not the evidence in Table 2.1 supports the original hypothesis that FF-MAS activates the specific membrane receptor, LXR alpha.

Explain your answer.

..................................................................................................................................

.............................................................................................................................. [1]

(ii) State the conclusions that can be drawn from the results in Table 2.1.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

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..................................................................................................................................

.............................................................................................................................. [3]

[Total: 11]

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DC (NH/DJ) 43384© UCLES 2011 [Turn over






*6748637284*

BIOLOGY 9700/53


1 hour 15 minutes




1

2

Total

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2

9700/53/M/J/11© UCLES 2011

ForExaminer’s

Use

1 A student used the procedure outlined below to find the water potential of a plant storage tissue that has coloured cell sap.

• pieces of plant tissue are placed into different sucrose solutions of known concentrations to allow osmosis to occur

• damaged cells release pigment that colours the sucrose solutions that bathe the tissue

• the water potential of the sucrose solutions may change as a result of osmosis

• sucrose solutions become less dense if they gain water from the tissue

• a pipette is filled with the coloured sucrose solution that has bathed the plant tissue

• a drop of the coloured bathing sucrose solution is released half way down a tube of sucrose solution of the same concentration as the original bathing solution as shown in Fig. 1.1

• the direction and rate of movement of the drop of coloured solution is determined by its density

coloured sucrosesolution collectedin pipette

sucrose solution ofsame concentrationas original bathingsolution

released droplet

coloured bathingsucrose solution

Fig. 1.1

Fig. 1.2 shows the results that the student plotted from the investigation.

0.0.0 0 20.2 0 40.4 0 80.8 1 01.0.00.0

1.0

2.0

3.0

4.0

–1.0

–2.0

–3.0

–4.0

0 2 0 4 0 8 1 0

rate ofmovementof released droplet

0.60.60.6


Fig. 1.2

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3


ForExaminer’s

Use

(a) Describe how the student could use this procedure to find the water potential of the plant storage tissue that has coloured cell sap.

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

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..........................................................................................................................................

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..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

..........................................................................................................................................

...................................................................................................................................... [8]

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(b) (i) Suggest suitable units for the rate of movement of the drop.

.............................................................................................................................. [1]

(ii) State how the student would estimate the water potential of the plant tissue.

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [2]

(c) (i) Identify the independent and dependent variables in this investigation.

independent .............................................................................................................

..................................................................................................................................

dependent ................................................................................................................

.............................................................................................................................. [2]

(ii) Identify two variables which the student may not have adequately controlled during the investigation.

1. ...............................................................................................................................

2. ........................................................................................................................... [2]

(iii) State how one of the variables you have identified in (c)(ii) may have influenced the results.

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [1]

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ForExaminer’s

Use

(d) The student made direct observations of the cells of the tissues that had been immersed in 0.2 mol dm–3 and 0.8 mol dm–3 sucrose solutions.

(i) Predict the appearance of the cells under the microscope when immersed in


..................................................................................................................................


.............................................................................................................................. [1]

Use the space below for any diagrams you include in your answer to (i).

(ii) Explain your answers to (d)(i).

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [2]

[Total: 19]

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ForExaminer’s

Use

2 One possible cause of infertility in women is the failure of immature oocytes to complete meiosis. Scientists studying the causes of infertility tested a naturally occurring compound, FF-MAS, to find out how it stimulates meiosis to restart in oocytes.

One hypothesis is that FF-MAS activates a specific membrane receptor, LXR alpha. This hypothesis was tested on mice using FF-MAS and three compounds known to activate this receptor in other cells.

The main stages of the experimental procedure were

• immature female mice were injected with follicle stimulating hormone (FSH) and their ovaries removed 48 hours later

• the oocytes were isolated and cultured in a medium that maintains them at the primary oocyte stage of development

• different concentrations of the test compounds were added to separate cultures of oocytes

• the whole procedure was repeated for each compound

• the effect of each test compound on meiosis was recorded after 24 hours

• the mean percentage of cells showing stimulation of meiosis was calculated together with the standard error (SM)

Table 2.1 shows the results of this investigation.

Table 2.1

mean percentage stimulation of meiosis ± SM

compoundconcentration of the activator compound added to the oocytes / μmol dm–3

0.00 0.07 0.70 7.00

FF-MAS 11.9 ± 2.6 11.5 ± 3.2 39.0 ± 5.6 86.1 ± 1.7

cholesterol 9.6 ± 1.6 13.8 ± 2.9 12.5 ± 2.7 15.5 ± 2.7

22R-HC 10.5 ± 1.3 14.7 ± 6.2 15.8 ± 1.6 6.0 ± 1.2

25-HC 15.1 ± 2.6 15.0 ± 2.2 9.8 ± 0.3 14.1 ± 1.7

(a) (i) Suggest why the mice were treated with FSH before the ovaries were removed.

..................................................................................................................................

.............................................................................................................................. [1]

(ii) Suggest the purpose of keeping the oocytes in a medium that maintains them at the primary oocyte stage.

..................................................................................................................................

.............................................................................................................................. [1]

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Use

(b) Explain what SM shows about the mean percentage values.

..........................................................................................................................................

...................................................................................................................................... [1]

Statistical tests were carried out to compare the stimulatory effects on meiosis of FF-MAS with the effects of the other compounds at each of the three concentrations used.

(c) (i) State the null hypothesis for these tests.

..................................................................................................................................

.............................................................................................................................. [1]

(ii) State a statistical test that could be used and give the reason for your choice.

test ...........................................................................................................................

reason for your choice ..............................................................................................

.............................................................................................................................. [2]

(iii) The result of the statistical test comparing FF-MAS with 22R-HC at 0.70 μmol dm–3 was significant at 0.05 probability level. Explain what this means.

..................................................................................................................................

.............................................................................................................................. [1]

(d) (i) State whether or not the evidence in Table 2.1 supports the original hypothesis that FF-MAS activates the specific membrane receptor, LXR alpha.

Explain your answer.

..................................................................................................................................

.............................................................................................................................. [1]

(ii) State the conclusions that can be drawn from the results in Table 2.1.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [3]

[Total: 11]

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