9700_s06_qp_4
A paper of Biology, 9700
Questions:
7
Year:
2006
Paper:
4
Variant:
0
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1
The metabolic pathway in which a hexose sugar, such as glucose, is broken down in respiration by cells starts with glycolysis. outlines the key stages of glycolysis. hexose triose phosphate 2ATP 2ADP 2ATP reduced NAD NAD pyruvate A State where in the cell glycolysis takes place. Name substance A. Explain why the hexose is converted to substance A. Examiner’s Use Briefly describe what happens to pyruvate if yeast is deprived of oxygen.
12. Energy and respiration  →  12.2. Respiration
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2
Use shows the results of experiments investigating the effect of different light intensities on the rate of photosynthesis of cucumber plants measured as mm3 CO2 uptake per cm2 leaf area per hour. The experiments were carried out at two different temperatures and two different carbon dioxide concentrations. light intensity / arbitrary units rate of photosynthesis /mm3 cm-2 h-1 A B C key A 0.04% C02 20°C B 0.04% C02 30°C C 0.13% C02 30°C With reference to , describe the shape of curve A, Examiner’s Use explain the reasons for the difference between curves B and C. Suggest two ways in which a commercial grower of cucumbers may increase the yield of the growing crop.
13. Photosynthesis  →  13.2. Investigation of limiting factors
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3
Use During the process of the excretion of nitrogenous waste in mammals, blood passes from the renal artery into networks of capillaries called glomeruli. is an electronmicrograph showing the relationship between the capillaries and the renal capsule cells, called podocytes. Name structures A and B. A B Draw an arrow, on , to show the passage of fluid out of the capillary. Name the fluid that collects in the capsular space. Describe how the composition of this fluid differs from blood plasma. Examiner’s Use Ultrafiltration involves the removal of small molecules, including urea, from the blood into the renal capsule. Explain what is required for ultrafiltration to occur.
14. Homeostasis  →  14.1. Homeostasis in mammals
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5
Use The summer squash plant produces fruit that are either white or yellow in colour and are either shaped like a disc or a sphere. The dominant phenotypes are white and disc- shaped fruit. Using the symbols A for white and a for yellow and B for disc and b for sphere, draw a genetic diagram to show what proportion of offspring will have yellow and sphere-shaped fruit if a white and disc-shaped fruit plant, heterozygous for both genes, is self-fertilised. Examiner’s Use Sickle cell anaemia is a blood disease that is frequently fatal when homozygous. It is caused by an autosomal recessive allele. Heterozygotes have sickle cell trait and appear normal. Malaria is a potentially fatal infectious disease of the blood caused by the protoctist, Plasmodium. In parts of the world where malaria is endemic the frequency of the sickle cell allele is high. Explain the possible health consequences, in such areas, for a person who is homozygous dominant and for a person who is homozygous recessive for the sickle cell allele. homozygous dominant for the sickle cell allele homozygous recessive for the sickle cell allele. Explain why heterozygotes have a strong selective advantage in areas where malaria occurs.
16. Inheritance  →  16.2. The roles of genes in determining the phenotype
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