0610_w10_qp_32
A paper of Biology, 0610
Questions:
6
Year:
2010
Paper:
3
Variant:
2
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1
For Examiner's Use A shows a buttercup, Ranunculus cymbalaria. B shows details of a flower of the same plant. A B Explain, using only features visible in , why Ranunculus cymbalaria is classified as a dicotyledonous plant rather than as a monocotyledonous plant. For Examiner's Use shows a transverse section through a buttercup root at the end of the cold winter (W) and at the end of the warm, moist summer (S). At the end of the winter, the cells contain very few starch grains. At the end of the summer, most of the root cells contain many starch grains. W S Suggest why there are few starch grains in the cells of W compared with a large number of starch grains in the cells of S. Describe how enzymes in root cells synthesise starch. For Examiner's Use As temperature is increased, for example from 10 oC to 30 oC, enzyme activity increases. Explain how increasing temperature affects enzyme activity.
3. Movement into and out of cells  →  3.2. Osmosis
6. Plant nutrition  →  6.2. Leaf structure
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2
For Examiner's Use Define the term excretion. shows a dialysis machine for treating people who have kidney failure. The dialysate (dialysis fluid) is a solution of glucose and salts. blood out blood in dialysate out blood vessels dialysate in dialysis membrane Explain how, when the patient is receiving dialysis treatment the loss of plasma proteins and red blood cells is prevented, For Examiner's Use the normal glucose concentration of the blood is maintained. For Examiner's Use A person with kidney failure received regular dialysis treatment for 17 days. shows how the concentration of urea in the blood changed over the 17 days. concentration of urea in the blood / mg per dm3 time / days State how many times the person received dialysis treatment. Calculate the decrease in the concentration of urea in the blood from the beginning of dialysis until the end of the treatment. For Examiner's Use Describe the changes that occur in the urea concentration in the blood over the period shown in . You will gain credit for using the data in in your answer. Explain the changes in urea concentration in the blood as shown in .
13. Excretion in humans  →  13.1. Excretion in humans
14. Coordination and response  →  14.4. Homeostasis
3. Movement into and out of cells  →  3.2. Osmosis
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3
For Examiner's Use In the space below write a balanced chemical equation for anaerobic respiration in muscles. …….…………………….………  ………………… … ………… Some students investigated the breathing of a 16-year old male athlete. shows the pattern of his breathing for 60 seconds when resting. shows the pattern of his breathing while he took some exercise for 60 seconds. time / s volume of air / dm3 time / s volume of air / dm3 For Examiner's Use Table 3.1 shows a summary of the results obtained by the students. Table 3.1 breathing at rest breathing during exercise volume of air breathed in with each breath / dm3 0.5 …………………………… rate of breathing / number of breaths per minute …………………………… volume of air breathed in per minute / dm3 5.5 …………………………… Using information from , complete Table 3.1. Write your answers in Table 3.1. Explain the effect of exercise on the student’s breathing. For Examiner's Use During strenuous exercise, the hormone adrenaline causes changes in the pulse rate and in the concentration of glucose in the blood. Explain the importance of these changes during strenuous exercise. pulse rate concentration of glucose in the blood
12. Respiration  →  12.3. Anaerobic respiration
11. Gas exchange in humans  →  11.1. Gas exchange in humans
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5
For Examiner's Use In many parts of the world, raw sewage drains into rivers. Raw sewage contains organic matter which acts as food for bacteria. The breakdown of organic matter by bacteria has an effect on the oxygen concentration and species of invertebrate animals in rivers. shows the changes in oxygen concentration along a river. A sampling stations B C D E F G distance downstream sewage enters river concentration of dissolved oxygen / % of maximum saturation Table 5.1 shows the invertebrate animals at seven sampling stations, A to G, along the river. invertebrate animal present A B C D E F G stonefly nymph freshwater shrimp caddis fly larva mayfly nymph midge larva rat-tailed maggot water louse wandering snail tubifex worm ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ invertebrate animals sampling stations key Table 5.1 For Examiner's Use Describe the changes that occur to the oxygen concentration in the river as shown in . You will gain credit for using the data in in your answer. Name the invertebrate animal that is only found in water with the highest oxygen concentration. Name the two invertebrate animals that tolerate the lowest oxygen concentrations. Suggest and explain the changes in the number of different species of invertebrate animals along the river, as shown in Table 5.1. For Examiner's Use Sewage treatment works receive raw sewage. This sewage contains food molecules, such as cellulose, starch, protein and fat. Explain how bacteria breakdown these nutrient molecules. The concentration of nitrate ions is often very high in the water leaving a sewage treatment works. In some places, the water passes through a series of reed beds as shown in . The water leaving the reed beds and entering the river contains very low concentrations of nitrate ions. water from sewage works river reeds gravel For Examiner's Use Explain two ways in which the concentration of nitrate ions may be reduced as the water flows through the reed beds. Some bacteria that live in reed beds release methane. Other sources of methane are cattle and flooded rice fields. Explain the environmental consequences of an increase in the methane concentration in the atmosphere.
20. Human influences on ecosystems  →  20.3. Pollution
3. Movement into and out of cells  →  3.2. Osmosis
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6
For Examiner's Use Define the term self-pollination. Snapdragon plants have flowers with three colours: red, pink and white. Some students investigated the inheritance of flower colour in snapdragons. In cross 1 they cross-pollinated plants that were homozygous for red flowers with plants that were homozygous for white flowers. They collected and planted the seeds from cross 1. All of the resulting plants had pink flowers. In cross 2 they self-pollinated all the pink-flowered plants and found that in the next generation there were red-flowered plants, white-flowered plants and pink-flowered plants. Complete the genetic diagrams to show how flower colour is inherited in snapdragon plants. Use the symbol IR for the allele for red flowers and IW for the allele for white flowers. cross 1 parental phenotypes parental genotypes gametes offspring genotypes offspring phenotypes red flowers × × pink flowers white flowers For Examiner's Use cross 2 parental phenotypes parental genotypes gametes pink flowers × × pink flowers offspring genotypes …………………………………………………………………………………………. ratio of offspring phenotypes ……………………………………………………………………………………… Another student cross-pollinated pink-flowered plants with white-flowered plants. Complete the genetic diagram to show the results that the student would expect. phenotypes genotypes gametes pink flowers × × white flowers offspring genotypes …………………………………………………………………………………………. ratio of offspring phenotypes ……………………………………………………………………………………… For Examiner's Use Explain the advantages of sexual reproduction to a species of flowering plant, such as the snapdragon.
16. Reproduction  →  16.3. Sexual reproduction in plants
17. Inheritance  →  17.4. Monohybrid inheritance
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