CE Biology 2006 MS

8/6/2019 CE Biology 2006 MS

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~'-:arksI Section A I

1. (a) low .(b) gravity e (c) muscle .(d) valves .(e) close .

Total: 5 marks

2 . (a) 150mL 1(b) saliva, mucus, gastric juice, pancreatic juice, bile, intestinal juice (any two) 1, 1(c) (i) The small intestine is longer than the large intestine ..

so the time for water absorption is longer / surface area for water absorption is larger .. anyonesethe inner wall of the small intestine is highly folded / has a large number of villi ..

Thus the surface area for water absorption is larger ..(ii) The absorption of digested food into blood increases the water potential of the gut content

As a result, water is drawn into the blood b osmosis ..E ective Communication (C 1

Total: 7 marks

(a) *cerebellum .It is for coordinating the activities of muscles in maintaining body balance .

(b) Z protects Y from mechanical damage ..(c) Drawing of different neurones (D): correct position of cell bodies, presence of2 synapses only.. ' l 2 , Y z

* Labels (L): receptor / nerve ending, sensory neurone, interneurone, motor neurone,effector / biceps / muscle (any four) 4 x Y z

Correct pathway (P): Indicate the direction of nerve impulse transmissionOr direction can be identified from the label(s) of the component .

senso neurone

interneurone


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4. (a) * Mitotic cell division 1 +This ensures that all the GM corn plants produced carry the inserted gene / are genetically identical 1

(b) Itmay kill some other insects / lead to a drop in the insect population .thus resulting in the extinction of the species / reduction of biodiversity . r n[][ T I

anyoneset

Itmay kill some beneficial insects .which may help the pollination of other plants '" .If the corn grains are dispersed into the natural environment, .the plants formed will outcompete / displace some other species .'" .

due to its resistance to insects(accept other reasonable answers)

(c) Increase the ability of producing vitamins, e.g. vitamin A ~to increase the nutritive value of the food produced L ! J any

onesetncrease the ability to fix nitrogen / nitrogen fixation 1 1 l

to increase protein content of the food produced ~(accept other reasonable answers)Total: 6 marks

. (a) (i) slightly overweight .(ii) 49.0-56.5 kg .

(b) (i) apple shape '" .(ii) WHR ofMr Wong =0.90, thus he is of pear shape .

WHR of Mrs Wong =0.92, thus she is of apple shape .Mrs Wong has a higher health risk .

(c) This diet has high content of dietary fibre .which is indigestible / add bulks to the food to give the sense of fullness .Italso has low fat content .and hence the overall energy intake through this diet will be lowered .reducin the chance of obesity

Total: 10marks

. (a) Over-consumption of fossil fuels will generate a large amount of carbon dioxide .Deforestation leads to a decrease in the overall photosynthetic activity 00 and hence a reduction in the removal of carbon dioxide from the atmosphere .As a result, the carbon dioxide concentration in the atmosphere increases .This will trap more heat radiated from the Earth's surface / increase the greenhouse effect .resultin in lobal warming

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(b) Soil erosion increases as a result of deforestation .because rain falls onto the soil directly without the covering of canopy

/ there is no root systems to hold soil together .The riverbed of the lower course of the river rises due to sedimentation

/ rainwater tends to run off on the soil surface leading to a sudden rise in the volume of water .....Thus the river is more likely to floodSoil erosion occurs as a result of deforestation 0he riverbed in the lower course of the river rises due to increased sedimentation 1Due to deforestation, rainwater tends to run off on the soil surface resulting ina sudden rise in the volume of water :.......................... 1Thus the river is more likely to flood

anyoneset

(c) Because the rate of regeneration of the fossil fuels is too slow to have a sustainable supply forhuman consumption .

(d) solar energy / wind / tidal waves / hydroelectric power .It is not feasible becausethe production of energy from this source is not cost-effective in large scale power generation

/ there is not enough land available for large-scale electricity generation by wind / solar energy // the tidal waves or rivers in HK are too small for power generation .

(accept alternative answers / approaches)Total: II marks

(a) 4thto 8thMarch .There is a great drop in the thickness of the uterine lining in this period ..

(b) 12tht02IstMarch 1The rise in body temperature indicates that / Uterine lining is thickened and ready for implantation.. 1ovulation occurs at around day 17 1Also, sperms and the egg can survive for a couple of days in the female reproductive tract 1If sexual intercourse occurs in this eriod, there is a high chance of regnancy

E ective Communication (C 1(c) This method only allows her to detect ovulation when there is a rise in the body temperature .

But it fails to predict the fertile period before ovulation .Total: 8 marks

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I Section B I8. (a) (i) Measure the displacement of the solution level in the graduated tube .

(ii) Title (T) .Correct choice of axes (A) Y oCorrect labelling of axes together with units (L) ..Correct plotting and joining of points (P) I l iz

~' 7 : : : : 4 s"'66';;'3.u ;'l).:::. . . . ,~rn820.:::0..

4-


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(3) The X chromosome carries some vital genes r nthat are essential to the survival of the zygote and it subsequent development 1Trese genes are absent in the Y chromosome :.................................... 1 anyThe X chromosome carries more genes than the Y chromosome r nAbsence of the X chromosome will result in the Joss of some genes 1that may be essential to the survival of the zygote and its subsequent development 1(accept other reasonable answers)

oneset

Total: 7 marks

9. (a) (i) (1) 6566.7% .(2) The urea content in urine is much higher because a large amount of water

is reabsorbed / the amount of water reabsorbed along the kidneytubule is relatively much greater than that of urea .

(ii) The water content of glomerular filtrate is greater than that of the plasma .because protein is too large to pass the wall of the glomerulus and

that of the Bowman's capsule .The proportion of water in the glomerular filtrate thus increases ..

(iii) The person cannot produce sufficient insulin .to stimulate liver cells to convert glucose into glycogen ..The level of glucose in the blood may become so high / exceed the threshold value .that glucose cannot be completely reabsorbed in the kidney ..Thus it a ears in the urine

Total: 9 marks(b) (i) Living cells are not required in the transport of water up the stem .

(ii) Water is transported up the stem mainly by transpiration pull .which is resulted from a physical process and thus can occur outside living cells .The transport of water occurs in dead xylem vessels .

which remains functional even in the treated plants(iii) Immerse the cut end of the small plant in a dye solution .After a few hours, cut a thin section of the upper part of the stem .

Identify the cell type stained by the dye under the microscope .(iv) The woody stem is mainly supported by mechanical strength / rigidity / hardness .

of the thick-walled cells / xylem vessels .Total: 9 marks

10. (a) (i) The average dry mass of both samples decreases from day 0 to day 12 .because the stored food in seed .is used in respiration / is broken down to carbon dioxide and water ..


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Marks(ii) The average dry mass of the seedlings grown in daylight increases from day 12 to day 18,

while that of seedlings grown in darkness continues to decrease .because under daylight, the seedlings have developed green leaves .for pMtosynthesis .The rate of food production is faster than the rate of food consumption .resultin a net ain in d mass

(iii) The dry mass shows the actual biomass / organic matter of the seedlings /The water content of the seedlings varies and hence the fresh mass cannot indicatethe actual biomass .

Total: 8 marks(b) (i) Oxygen uptake increases with exercise of increasing energy requirement .

(ii) Oxygen content in aorta: 19 mL per 100 mL bloodOxygen content in vena cava: 5.6 mL per 100 mL blood (1 or 0)

(iii) Difference in oxygen content for running = = 19 - 6 = = 13 mL per 100 mL blood ..Difference in oxygen content for cycling = = 19 - 10 = = 9 mL per 100 mL blood .

(iv) The difference in blood oxygen content between the aorta and the vena cava increaseswith increased exercise intensity .

This is because that more oxygen is consumed by tissue .for respiration to release more energy for increased exercise intensity ..

(v) During vigorous exercise, there is an increase in ventilation rate / rate and depth of breathingThe oxygen content in air sac increases ..The diffusion gradient across alveolar wall increases / This

increases the diffusion of oxygen into the blood ..thus maintaining the blood oxygen content of the aorta at a constant and high levelTotal: 10 marks

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CE Biology 2006 MS