9700_s05_qp_2
A paper of Biology, 9700
Questions:
6
Year:
2005
Paper:
2
Variant:
0
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2
is a drawing of a transverse section of a leaf. Use label lines and the letters X, S, E and D to indicate the following on : X – a xylem vessel S – a phloem sieve tube E – a lower epidermal cell D – a palisade mesophyll cell Calculate the magnification of . Show your working and express your answer to the nearest whole number. Answer 0.5 mm Use [T Name two assimilates that move from the palisade mesophyll cells to the vascular tissue to be exported from the leaf. Explain, using the term water potential, how water moves from the vascular tissue to the atmosphere. Examiner s Use
4. Cell membranes and transport  →  4.2. Movement into and out of cells
7. Transport in plants  →  7.2. Transport mechanisms
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3
As blood passes through the capillaries in the lungs it becomes oxygenated. Explain how the structure of haemoglobin aids the uptake of oxygen in the lungs. shows the dissociation curve of adult haemoglobin. Use partial pressure of oxygen / kPa Percentage saturation of haemoglobin with oxygen [T Use the information given in to complete the table below. During exercise the concentration of carbon dioxide in muscle tissue increases. This stimulates an increase in the release of oxygen from the blood. Explain how carbon dioxide stimulates the release of oxygen from the blood. Examiner s Use part of the circulation partial pressure of percentage saturation oxygen / kPa of haemoglobin capillaries in the lungs capillaries in muscle tissue at rest capillaries in muscle tissue during 2.0 strenuous exercise
8. Transport in mammals  →  8.2. Transport of oxygen and carbon dioxide
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4
Collagen is found in the extracellular matrix of muscles, tendons, ligaments and bones. Fibroblast cells in these tissues make collagen by synthesising polypeptides that form molecules with a triple helix shape. These are secreted from fibroblasts into the extracellular matrix where enzymes assemble them into collagen fibres. is a diagram summarising these events. Name the processes occurring at A, B and C. A B C Use fibroblast cell extracellular matrix triple helix molecules being assembled into collagen fibres endoplasmic reticulum DNA A F E B D C not drawn to scale cytoplasm nucleus [T Name structures D and E. D E Name molecule F. F Collagen is continuously broken down in the extracellular matrix by the enzyme collagenase, which catalyses the hydrolysis of the peptide bond between the amino acids glycine and isoleucine. Suggest how collagenase is only able to act on the peptide bond between glycine and isoleucine and not on peptide bonds between any other amino acids. Draw a diagram below to show how the peptide bond between glycine and isoleucine is broken by hydrolysis including the product or products. N C C N C H O H CH CH3 CH2 CH3 H H O C Examiner s Use
2. Biological molecules  →  2.3. Proteins
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5
The eelgrass, Zostera, is a marine plant that forms dense vegetation in shallow coastal waters. The primary consumers in this ecosystem eat the eelgrass and the photosynthetic algae that grow on its surface. shows the flow of energy through an eelgrass ecosystem. The figures in circles represent the energy transfer in kJ m–2 yr–1. carnivorous birds invertebrate predators, e.g. crabs fish 2.5 detritus feeders, suspension feeders, grazers 1.05 x 106 eelgrass and photosynthetic algae sunlight dead plants and animals from other ecosystems Use [T Calculate the percentage of energy transferred from primary consumers to the secondary consumers in the ecosystem shown in . Show your working and express your answer to the nearest whole number. Answer …………………… Explain why little of the energy present in producers is transferred to the secondary consumers. Dead plants contain nitrogen in the form of proteins. These are decomposed by bacteria. Outline how bacteria convert nitrogen in these proteins to a form that may be taken up by living plants. Examiner s Use
13. Photosynthesis  →  13.1. Photosynthesis as an energy transfer process
13. Photosynthesis  →  13.2. Investigation of limiting factors
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6
Substances are exchanged between the plasma, tissue fluid, lymph and red blood cells. Complete the table below to show which of the statements apply to each of these components of the body. Fill in each box using a tick (✓) to show that the statement applies or a cross (✗) if it does not. The first row has been completed for you. Nicotine is the drug in tobacco smoke. State two effects of nicotine on the cardiovascular system. Use cytoplasm statement plasma tissue fluid lymph of red blood cells formed by leakage from capillaries ✗ ✔ ✗ ✗ contains haemoglobin contains water contains antibodies in direct contact with muscle cells [T Table 6.1 shows information on smoking and lung cancer in six countries. Table 6.1 shows: • the percentage of male and female adults who smoke regularly in each country; • the death rates from lung cancer expressed as deaths per 100 000 of the population of each country. Table 6.1 Explain whether or not there is any evidence in Table 6.1 to support the following statements. Use the data in the table to support your answer. Men are more at risk of dying from lung cancer than women. Countries where a high percentage of the population smoke have high death rates from lung cancer. Examiner s Use percentage of the deaths from lung cancer / country population who smoke deaths per 100 000 males females males females China 53.4 4.0 22.7 10.5 France 33.0 21.0 73.3 14.4 Malaysia 49.2 3.5 5.6 2.3 New Zealand 25.1 24.8 47.3 29.2 South Africa 43.8 11.7 13.8 5.4 Trinidad and Tobago 42.1 8.0 12.3 4.2 Table 6.1 shows that a larger percentage of men in some countries, such as Malaysia, smoke compared with New Zealand. It also shows that the death rate from lung cancer for men in Malaysia is much lower. Suggest two other pieces of information about men who smoke that would be useful in evaluating the risks of developing lung cancer. Examiner s Use
9. Gas exchange  →  9.1. The gas exchange system
8. Transport in mammals  →  8.1. The circulatory system
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