9700_s07_qp_2
A paper of Biology, 9700
Questions:
6
Year:
2007
Paper:
2
Variant:
0
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1
is a drawing made from an electron micrograph of a cell from the ciliated epithelium of the bronchus. A B C D E F G H I J A B C D E F G H I J Examiner’s Use Complete the table below by writing the appropriate letter from to indicate the structure that carries out each of the functions listed. The first one has been completed for you. function structure facilitated diffusion of glucose B creates a current to move mucus aerobic respiration makes ribosomes a site of transcription packages proteins into lysosomes The alveoli in the lungs are lined by a squamous epithelium. Explain why gas exchange occurs in alveoli and not in the bronchus. Describe the likely appearance of the lining of the bronchus in a person who has been a heavy smoker for many years.
9. Gas exchange  →  9.1. The gas exchange system
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2
Use Describe how enzymes take part in chemical reactions. Starch phosphorylase is an enzyme found in plant cells. In potato tuber cells, the enzyme takes part in the breakdown of starch when the tuber begins to grow. starch phosphorylase starch + phosphate ions glucose 1-phosphate A student investigated the effect of pH on this reaction using two buffer solutions. The student prepared four test-tubes, A to D, as shown in Table 2.1 and described below. The student made an extract of potato tissue that contained the enzyme. Some of this extract was boiled. A solution of potassium dihydrogen phosphate was added to some tubes as a source of phosphate ions. The test-tubes were left for ten minutes in a water bath at 30 °C and then samples were tested with iodine solution. Examiner’s Use Table 2.1 test- tube contents volume of starch solution / cm3 volume of glucose 1-phosphate solution / cm3 volume of potassium dihydrogen phosphate solution / cm3 pH of buffer solution enzyme extract results with iodine solution after ten minutes A 0.5 6.5 unboiled negative B 0.5 2.0 unboiled positive C 0.5 6.5 boiled positive D 6.5 boiled negative State what the student would conclude from a positive result with iodine solution. Explain why the student boiled some of the extract in this investigation. Explain the results shown in Table 2.1.
3. Enzymes  →  3.2. Factors that affect enzyme action
2. Biological molecules  →  2.1. Testing for biological molecules
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3
Use Muntjac are small deer found throughout Asia. Cells at the base of the epidermis in the skin continually divide by mitosis. shows the chromosomes from a skin cell of a female Indian muntjac deer at metaphase of mitosis. X State the diploid chromosome number of the female Indian muntjac deer. Name X and state its role in mitosis. name role On , shade in a pair of homologous chromosomes. In the space below, draw one of the chromosomes shown in as it would appear during anaphase of mitosis. Examiner’s Use Outline what happens to a chromosome between the end of anaphase and the start of the next mitosis. During the formation of eggs in the ovary of the female Indian muntjac deer, the chromosome number changes. State what happens to the chromosome number and explain why this change is necessary.
5. The mitotic cell cycle  →  5.2. Chromosome behaviour in mitosis
16. Inheritance  →  16.1. Passage of information from parents to offspring
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4
shows the movement of sucrose from source to sink through the phloem in a plant. water water water water Key C source sink sucrose molecules chloroplast sucrose made in cytoplasm starch grain sucrose glucose + fructose water D Examiner’s Use With reference to , name an example of a source and a sink source sink name cells C and D. C D With reference to , explain how sucrose travels from, the source to cell C cell C to the sink. Explain why multicellular plants require transport systems for substances, such as water and sucrose.
7. Transport in plants  →  7.2. Transport mechanisms
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5
Use Two people took part in a study to find out the effectiveness of two types of immunisation. Person A received an injection of antibodies against tetanus and person B received a tetanus vaccination. Over the new few weeks, the blood from these two people was analysed for the presence of antibodies to tetanus. The results are shown in A and B. antibody concentration / arbitrary units time / days B antibody concentration / arbitrary units time / days A booster vaccination Name the types of immunity shown by A and B. A B Examiner’s Use Explain why the antibody concentration in person A, decreased during the study period did not increase. Sketch on B, on page 10, what you would expect to happen to the antibody concentration if person B received a booster vaccination at day 60. Put your answer to this question on B on page 10. Explain why, in this investigation, the experimenters had to measure the concentration of antibodies to tetanus rather than the concentration of all antibodies in the blood of A and B.
11. Immunity  →  11.2. Antibodies and vaccination
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6
Use shows a diagram of a plasma (cell surface) membrane. K L N M Indicate, by putting a circle, , around one of the following, the width of the membrane shown in . 0.7 nm 7.0 nm 70 nm 7 × 10–5 m 700 µm 7.0 µm Outline the functions of the following components of the plasma membrane. K L M N Examiner’s Use Some substances may cross plasma membranes by simple diffusion. Glucose, however, does not. Explain why glucose cannot pass across membranes by simple diffusion. In an investigation, animal cells were exposed to different concentrations of glucose. The rate of uptake of glucose into the cells across the plasma membrane was determined for each concentration. shows the results. concentration of glucose / arbitrary units rate of uptake of glucose by cells / arbitrary units Using the information in , explain how the results of the investigation support the idea that glucose enters cells by facilitated diffusion. QUESTION 6 CONTINUES ON PAGE 14 Examiner’s Use State how active transport differs from facilitated diffusion.
4. Cell membranes and transport  →  4.2. Movement into and out of cells
8. Transport in mammals  →  8.2. Transport of oxygen and carbon dioxide
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