0610_s13_qp_33
A paper of Biology, 0610
Questions:
6
Year:
2013
Paper:
3
Variant:
3
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1
For Examiner's Use shows three annelid species and Ascaris lumbricoides, a species of nematode. Chaetopterus variopedatus Nereis diversicolor Lagisca flocculosa Ascaris lumbricoides annelids nematode not drawn to scale State three features shown by the three annelid species that are not shown by the nematode species. For Examiner's Use Organisms are given two names, e.g. Nereis diversicolor. State what is meant by the first name. N. diversicolor is a filter feeder. It filters plankton from sea water. Annelids like N. diversicolor form an important part of the ecosystems of estuaries. Fish feed on annelids when the sea covers the mud in the estuary. When the tide is out wading birds are the main predators of annelids. Birds of prey are the main predators of the wading birds. Explain the term ecosystem. Use the space below to draw a food chain for the estuary ecosystem when the tide is out. Describe the advantages of drawing a food web rather than a food chain for an ecosystem. For Examiner's Use The palolo worm is a species of annelid that lives on coral reefs in the Pacific Ocean. At certain times of the year, all the worms in an area leave their burrows to swim to the surface. They all release their gametes into the water at the same time. This is known as mass spawning. Suggest the advantages of having mass spawning occurring only at certain times of the year and not all year round. Meiosis is involved in producing gametes in palolo worms. Describe how meiosis differs from mitosis and explain why meiosis is important for the production of gametes.
19. Organisms and their environment  →  19.2. Food chains and food webs
1. Characteristics and classification of living organisms  →  1.1. Characteristics of living organisms
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2
For Examiner's Use Fanwort, Cabomba caroliniana, is an aquatic plant often used to provide oxygen in fish tanks. Some students investigated the effect of temperature on the rate of photosynthesis of C. caroliniana. The apparatus that they used is shown in . ruler oil droplet capillary tubing water with sodium hydrogencarbonate beaker of water Cabomba caroliniana thermometer bench lamp stopwatch Explain why: the lamp was kept at the same distance from the C. caroliniana throughout the investigation; the water was enriched with carbon dioxide by adding sodium hydrogencarbonate. For Examiner's Use The students determined the rate of photosynthesis by measuring the movement of the oil droplet along the glass tubing. Their results are shown in Table 2.1. Table 2.1 distance travelled by the droplet / mm per minute temperature / °C mean 3.7 12.0 15.0 20.0 40.0 4.3 0.7 Describe the effect of temperature on the rate of photosynthesis of C. caroliniana. For Examiner's Use Photosynthesis is a chemical process catalysed by enzymes. Explain how the results shown in Table 2.1 support the idea that enzymes are involved in photosynthesis. C. caroliniana originally grew only in Latin America. This plant has escaped into the wild in Australia where its rapid growth has reduced the biodiversity of many streams and rivers. Suggest why the growth of C. caroliniana in Australia is far greater than in Latin America.
6. Plant nutrition  →  6.1. Photosynthesis
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3
For Examiner's Use shows a diagram of a cell from the pancreas that secretes the hormone, insulin. A B C State one function of each of the parts of the cell labelled A, B and C. A B C Glucose in the blood is absorbed by liver cells and muscle cells. These cells convert glucose to glycogen for storage. Explain why glucose needs to be converted to glycogen for storage rather than remaining dissolved in the blood. For Examiner's Use Other cells in the pancreas secrete the hormone glucagon. Glucagon stimulates liver cells, but has no effect on muscle cells. State the effect that glucagon has on liver cells. State how hormones, such as glucagon and insulin, travel around the body. Hormone Growth Promotants (HGPs) are hormones. HGPs are used to improve the production of food from animals. Many of these HGPs are hormones that are secreted naturally by the gonads (ovaries and testes). Name two hormones that are secreted by the gonads. The hormones are given to cattle by placing implants behind the ears. These release the hormones slowly during the animal’s life time. The advantages of using HGPs in meat production are: • more meat is produced per animal; • a 15 to 30 % increase in growth rate; • a 5 to 15 % improvement in conversion of feed into meat; • a decrease in greenhouse emissions from cattle. Suggest: the advantages of an increase in the conversion of feed into meat for the farmer; For Examiner's Use how the use of HGPs leads to a decrease in greenhouse emissions from cattle. HGPs are used in animal production systems in North America and Australia. The European Union (EU) has banned the use of HGPs and the import of meat from countries where the hormones are used. Suggest reasons for the ban on the use of HGPs in the EU.
14. Coordination and response  →  14.3. Hormones
14. Coordination and response  →  14.4. Homeostasis
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4
For Examiner's Use Blood is distributed through the body of a mammal in blood vessels. The blood supply to muscles changes considerably at the start and at the end of exercise. shows a cross section of a blood vessel as seen with an electron microscope. cell X liquid Y Z Name: cell X; liquid Y; the type of blood vessel shown in . State three substances that move across the wall of the blood vessel at Z. For Examiner's Use Table 4.1 shows the distribution of blood to different organs at rest and during exercise. Table 4.1 blood flow / cm3 per minute regions of the body at rest during strenuous exercise percentage change / % heart muscle kidneys 1 200 -50 skeletal muscles 1 000 12 500 skin 1 900 liver and alimentary canal 1 400 -57 brain others -33 total 5 600 17 500 Calculate the percentage change in the blood supply to the skeletal muscles. Show your working. Write your answer in Table 4.1. For Examiner's Use Explain why it is necessary for the blood supply to muscles to increase during exercise. The volume of blood to different organs varies as shown in Table 4.1. During exercise, blood flow to the skin increases and to the kidneys decreases. Describe the changes that occur in blood vessels to cause blood flow to increase and to decrease. increase blood flow decrease blood flow
11. Gas exchange in humans  →  11.1. Gas exchange in humans
12. Respiration  →  12.3. Anaerobic respiration
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6
For Examiner's Use Many biologists study populations of organisms in their natural habitats. Define the term population. Question 6 continues on page 18. For Examiner's Use A 10-year study was carried out to investigate the relationship between voles and owls. Voles are small mouse-like mammals and owls are carnivorous birds. The results are shown in and . time / years 45 000 40 000 35 000 30 000 25 000 20 000 15 000 10 000 5 000 number of voles time / years number of owls For Examiner's Use Suggest three reasons for the decrease in the population of voles between years 5 and 6. State the evidence from and that supports the idea that voles form a large part of the food eaten by owls.
19. Organisms and their environment  →  19.4. Populations
20. Human influences on ecosystems  →  20.4. Conservation
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