0610_w14_qp_32
A paper of Biology, 0610
Questions:
6
Year:
2014
Paper:
3
Variant:
2
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1
is a photomicrograph of a leaf of the tea plant, Camellia sinensis. A B C D E Name A to E. A B C D E shows a cell from region B of the leaf shown in . F G H J K L Use the letters from to complete Table 1.1. Write one letter only in each box to identify the function. You may use each letter once, more than once or not at all. Table 1.1 function letter from controls movement of substances into and out of the cell exerts a pressure to help maintain the shape of the cell produces sugars using light as a source of energy withstands the internal pressure of the cell controls all the activities of the cell The enzyme catalase is found in lettuce leaves. A student investigated the activity of this enzyme by grinding some lettuce leaves and adding them to a solution of hydrogen peroxide. The volume of oxygen produced was measured until the reaction stopped. The student’s results are shown in . × × × × × × × × × × × × × volume of oxygen collected / cm3 time / s Describe the results shown in . You will gain credit if you use the data in your answer. Explain the action of enzymes during a reaction.
5. Enzymes  →  5.1. Enzymes
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2
Define the term excretion. is a diagram of a kidney tubule and its blood supply. blood blood The concentrations of solutes in the fluids at regions 1, 2, 3 and 4 were determined. The results are shown in Table 2.1. Table 2.1 substance concentration / g dm–3 region 1 region 2 region 3 region 4 glucose 0.9 0.9 0.2 0.0 protein 82.0 0.0 0.0 0.0 salts 8.0 8.0 9.6 16.5 urea 0.2 0.2 0.2 20.0 State the substance or substances in Table 2.1 which: has molecules which are too large to be filtered; has molecules which are small enough to be filtered but is completely reabsorbed from the fluid in the kidney tubule; increases in concentration as fluid moves along the kidney tubule. State three structures through which the fluid from region 4 passes as it leaves the body. One role of the kidney is to maintain the concentration of the blood plasma. Name the process of maintaining constant conditions within the body.
13. Excretion in humans  →  13.1. Excretion in humans
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3
Sewage treatment works use bacteria to digest the waste matter. Waste matter contains complex organic compounds, such as starch, cellulose, protein and fat. shows a diagram of a sewage works with an aerobic digestion tank. The sewage works discharges clean water into a river. Downstream from the sewage works, water is removed to be used as drinking water for a nearby village. chlorine solids removed solids removed grit to landfill compressed air air effluent screens grit tank sedimentation tank aerobic digestion tank final sedimentation tank chlorination tank mixing paddle collection and pumping river Explain the roles of bacteria in the aerobic digestion tank shown in . shows that chlorine is added to water before it leaves the sewage treatment works. Explain why chlorine is added to the water.
10. Diseases and immunity  →  10.1. Diseases and immunity
20. Human influences on ecosystems  →  20.3. Pollution
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4
Mammals have a double circulatory system. Blood flows between: • the heart and the lungs • the heart and the rest of the body (systemic circulation). shows a cross-section of an artery. Explain how the structure of an artery, as shown in , is related to its functions. shows the total cross-sectional area of the blood vessels in the systemic circulation. It also shows the changes that occur in blood pressure and the speed of blood in the different blood vessels. aorta mean blood pressure / kPa total cross- sectional area of the blood vessels / cm2 speed of the blood / cm s–1 arteriesarterioles capillaries veins vena cava tissue fluid pressure velocity aorta vena cava State the maximum mean blood pressure in the aorta. Describe how mean blood pressure and speed of blood change with cross-sectional area of blood vessels, as shown in . blood pressure speed of blood Describe how substances move from the blood in the capillaries into the tissue fluid. Blood flows from arteries into arterioles before entering capillaries. Explain the role of the arterioles in the skin when a person is very cold.
9. Transport in animals  →  9.3. Blood vessels
9. Transport in animals  →  9.1. Circulatory systems
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5
is a diagram of the human immunodeficiency virus (H. X Y cell membrane of host cell Name the parts of the virus labelled X and Y. X Y State three ways in which the structure of bacteria differs from the structure of viruses. Sub-Saharan Africa has the highest proportion of the population living with HIV in the world. The World Health Organization estimates both the total number of people who live with HIV and the total number of people that are newly infected each year. shows the estimated numbers for sub-Saharan Africa between 1990 and 2010. Number of people living with HIV, sub-Saharan Africa. 1990–2010 Number of people newly infected with HIV, sub-Saharan Africa. 1990–2010 0.5 1.0 1.5 2.0 2.5 3.0 year year millions of people millions of people Summarise the changes between 1990 and 2009 in the number of people living with HIV and the number of people newly infected with HIV. number of people living with HIV number of people newly infected with HIV Suggest why in 2010 the number of people living with HIV increased but the number of newly infected people decreased. Describe three ways in which HIV is transmitted from infected to uninfected people. Describe the effects of HIV on the immune system.
16. Reproduction  →  16.6. Sexually transmitted infections
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6
Some pollutants are not broken down easily and remain in the environment for a long time. These are described as persistent pollutants. PCBs are a waste material from the manufacturing of electrical insulation. PCBs are one of the most persistent pollutants in the environment. Between 1947 and 1976, factories dumped large quantities of PCBs into the Hudson River in the USA. Studies measured the concentrations of PCBs in the tissues of organisms in a food chain in the sea near the Hudson River, as shown in . 11 400 – 17 300 concentrations of PCBs in arbitrary units 6 – 45 1.56 0.85 porpoise herring zooplankton phytoplankton not to scale Describe the results shown in . Suggest an explanation for the different concentrations of PCBs in the organisms of the food chain. PCBs are toxic to many organisms because they bind to a protein molecule known as AHR. The Atlantic tomcod, Microgadus tomcod, is a fish that lives in the Hudson River and other rivers nearby. 90% of the tomcod population in the Hudson River is resistant to the effects of PCBs. This is because these fish have a different type of AHR compared with other tomcod populations. Suggest how this resistance came about. Scientists predict that the proportion of fish resistant to PCBs will decrease if the concentration of PCBs in the river decreases. Suggest reasons why the proportion of fish with the altered AHR protein might decrease. Describe the problems caused by non-biodegradable plastics in the environment.
20. Human influences on ecosystems  →  20.3. Pollution
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