0610_s12_qp_32
A paper of Biology, 0610
Questions:
6
Year:
2012
Paper:
3
Variant:
2
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1
For Examiner's Use A shows a cell from the lining of the alimentary canal. B shows a cell from the lining of a kidney tubule. Both cells absorb substances into the blood. C C A B Name the structures labelled C on the cells in . List three substances that are absorbed by both cells shown in . Explain how both cells shown in are adapted for absorption of substances into the blood. Name the part of the alimentary canal that is lined by the cells shown in A.
13. Excretion in humans  →  13.1. Excretion in humans
7. Human nutrition  →  7.5. Absorption
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2
For Examiner's Use Define the term growth. Some students investigated the responses of tomato seedlings to receiving light from one side (unidirectional light). The students germinated tomato seeds in the dark and then placed the seedlings in test-tubes with water. The seedlings were treated in four different ways, E to H, as shown in . The responses of the seedlings are shown in . E F G H light cover that light cannot get through E F G H light For Examiner's Use Name the response shown by the tomato seedling, F, which has bent 90º towards the light. Using the results shown in , suggest what conclusions may be made about how the tomato seedlings detected the stimulus of unidirectional light. You may refer to the seedlings by the letters E to H. Explain the advantage of the response shown by seedlings to unidirectional light. Responses to light are coordinated by plant growth substances known as auxins. Explain the role of auxins in coordinating the response. For Examiner's Use Research workers in India tested the hypothesis that pigments in tomato seedlings detect blue light. They used a variety of tomato seedling that does not have the ability to make a certain pigment. These seedlings and a control group of seedlings were grown in the dark and then exposed to unidirectional blue light for 360 minutes. The scientists measured the degree of bending of the seedlings at intervals during the 360 minutes. Their results are shown in . time / min control group degree of bending no pigment Describe the results shown in . For Examiner's Use Suggest an explanation for the differences between the responses of the two groups of seedlings.
6. Plant nutrition  →  6.1. Photosynthesis
14. Coordination and response  →  14.5. Tropic responses
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3
For Examiner's Use The red slender loris, Loris tardigradus, is a nocturnal mammal that feeds at night on flowers, fruit and a variety of small animals. It is found in forest ecosystems in South Asia. shows a red slender loris. Explain the meaning of the term ecosystem. State three ways in which mammals, such as the red slender loris, differ from other groups of vertebrates. For Examiner's Use The large eyes of the red slender loris show that it is well adapted for a nocturnal way of life. Suggest other features that the animal is likely to have that are adaptations to being active at night. Two species of slender loris are found in Sri Lanka, the grey slender loris, L. lydekkerianus, and L. tardigradus. The International Union for Conservation of Nature describes the red slender loris as endangered. Horton Plains National Park in Sri Lanka is one of the few places where L. tardigradus is found. Discuss why areas of land, such as the Horton Plains National Park, must be conserved. State how scientists could show that two populations of slender loris belong to the same species or to two different species.
20. Human influences on ecosystems  →  20.4. Conservation
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4
For Examiner's Use shows a vertical section of a human heart. J M K L valve O valve N Identify the blood vessels labelled J to M. J K L M For Examiner's Use Sensors that detect changes in blood pressure were placed into the blood vessels surrounding the heart. Recordings were taken at the times when the ventricles contracted and when they relaxed. The blood pressures recorded are shown in Table 4.1. Table 4.1 blood pressure / kPa blood vessel contraction of the ventricles relaxation of the ventricles J 16.0 10.0 K 0.3 0.3 L 0.3 0.3 M 2.0 0.5 Explain why the pressure in blood vessel J is greater than the pressure in blood vessel M. Explain why the pressure in blood vessels K and L is much less than the pressure in blood vessels J and M. For Examiner's Use Explain how the valves at N and O maintain one-way flow of blood through the heart. Other than in the heart, state where valves similar to those at O are found in the circulatory system.
9. Transport in animals  →  9.2. Heart
9. Transport in animals  →  9.3. Blood vessels
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5
For Examiner's Use shows the human male reproductive system and part of the urinary system. A B C D E F G H J Complete Table 5.1 by identifying the structure in the male reproductive system shown in that carries out each of the functions listed. Write one letter only in each box. You may use the same letter more than once. There are some letters that you will not use. The first one has been done for you. Table 5.1 function structure stores urine A produces gametes produces seminal fluid moves gametes by peristalsis produces testosterone For Examiner's Use Describe how human male gametes differ from human female gametes. Some women have difficulty becoming pregnant. They can be helped by taking fertility drugs. They can also be helped by artificial insemination. Describe how fertility drugs help women to become pregnant. Describe how artificial insemination is carried out.
16. Reproduction  →  16.4. Sexual reproduction in humans
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6
For Examiner's Use Nitrogen gas makes up about 80 % of the Earth’s atmosphere. Only those organisms that are able to fix nitrogen can use it. All other organisms rely on the recycling of nitrogen from nitrogen-containing compounds, such as proteins and DNA. shows the nitrogen cycle on a small farm in Ghana. nitrogen (N2) in atmosphere ammonium ions (NH4 +) in bacteria in root nodules of legumes amino acids in bacteria in root nodules of legumes amino acids in legumes protein in legumes protein in goat urea in blood of goat amino acids in intestine of goat nitrate ions (NO3 –) in soil ammonium ions (NH4 +) in soil urea in urine of goat protein in faeces of goat Q P R S Q T U Complete Table 6.1 by identifying the processes, P to U, in the nitrogen cycle shown in . One process, S, has been completed for you. Table 6.1 stage process P Q R S deamination T U For Examiner's Use It is difficult to improve legume crops by traditional plant breeding methods. Scientists in Ghana have used a different approach. They exposed seeds of two varieties of winged bean, Psophocarpus tetragonolobus, to ionising radiation. Seeds that had been exposed to radiation (irradiated seeds) and seeds that had not been irradiated were grown under identical conditions. After 45 days, the numbers of root nodules on the plants that grew from these seeds were recorded. The dry mass of the root nodules on each plant was also determined and recorded. The results of the investigation are shown in Table 6.2. Table 6.2 variety 1 variety 2 feature non-irradiated irradiated non-irradiated irradiated mean number of nodules per plant at 45 days mean dry mass of nodules per plant at 45 days / g 0.09 0.21 0.14 0.24 Use the results in Table 6.2 to describe the effect of radiation on the plants in both varieties. For Examiner's Use Suggest and explain what happens to the seeds when they are exposed to ionising radiation. Researchers use plants that show useful features in selective breeding to improve varieties of the winged bean. The improvement of winged beans by selective breeding is an example of artificial selection. Suggest how selective breeding is carried out with plants. Scientists in Australia have put a gene from the bacterium Bacillus thuringiensis (Bt) into the cowpea, an important crop in Africa. This gene gives resistance against the cowpea pod borer, an insect pest that reduces the yield of cowpeas. Explain how the method used by the Australian scientists differs from the technique used by the Ghanaian scientists. For Examiner's Use Legumes, such as cowpeas and winged beans, are grown in between maize plants in a method known as intercropping. Suggest the advantages to farmers of growing legumes and maize together in the same field at the same time.
19. Organisms and their environment  →  19.3. Nutrient cycles
16. Reproduction  →  16.3. Sexual reproduction in plants
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