Cambridge A Level Biology 9700 — 2013 May/June Paper 1 · Variant 1

1 Which size ranges can be viewed using a light microscope? 1 2 3 4 1 nm 100 nm 1 µm 100 µm 1 mm A 4 only B 1 and 2 only C 2 and 3 only D 3 and 4 only

Mark scheme: D

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2 The diagram shows a mitochondrion drawn from an electronmicrograph. Y X The length of the mitochondrion from X to Y is 3000 nm. What is the magnification of the drawing of the mitochondrion? A ×100 B ×1000 C ×10 000 D ×100 000

Mark scheme: C

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3 What is the function of nucleoli? A formation and breakdown of the nuclear envelope B formation of centromeres C formation of ribosomes D formation of the spindle during nuclear division

Mark scheme: C

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4 The diagram shows a stage micrometer, with divisions 0.1 mm apart, viewed through an eyepiece containing a graticule. 0 10 20 30 40 50 60 70 80 90 10 What is the area of the field of view of the microscope at this magnification? (π = 3.14) A π × 12.5 × 12.5 = 4.9 × 102 µm2 B π × 50 × 50 = 7.9 × 103 µm2 C π × 125 × 125 = 4.9 × 104 µm2 D π × 250 × 250 = 2.0 × 105 µm2

Mark scheme: C

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5 Which organelles are required for the formation of the hydrolytic enzymes found in lysosomes? mitochondria A B C D rough Golgi endoplasmic apparatus reticulum

Mark scheme: A

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6 The diagram is taken from an electronmicrograph of a cell which secretes enzymes. Where are these enzymes made? A B C D

Mark scheme: C

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7 X and Y show the structures of two hexose sugars. CH2OH CH2OH C O C O H OH H H H H C C C C HO H HO H HO H HO OH C C C C H OH H OH X Y Which statement is correct? A X is found in amylopectin. B X is found in amylose. C Y is found in cellulose. D Y is found in glycogen.

Mark scheme: D

More questions on Carbohydrates and lipids

8 The structural formula of a carbohydrate molecule can be shown as: H C O H C OH HO C H H C OH H C OH CH2OH Which of the molecules could be represented by this formula? 1 α glucose 2 deoxyribose 3 ribose A 1 only B 2 only C 2 and 3 only D 1, 2 and 3

Mark scheme: A

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9 What occurs when sucrose is broken down to monosaccharides? A condensation of reducing sugars releasing water B condensation of reducing sugars using water C hydrolysis, releasing reducing sugars and releasing water D hydrolysis, releasing reducing sugars and using water

Mark scheme: D

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10 One naturally occurring polysaccharide is an unbranched chain of the molecule acetylglucosamine linked by β-1, 4 glycosidic bonds. There are –CH2OH groups that alternate on each side of the polysaccharide chain. Many hydrogen bonds form between these unbranched chains. Which polysaccharide has a structure similar to that described? A amylose B amylopectin C cellulose D glycogen

Mark scheme: C

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11 Which molecules have properties that are dependent on hydrogen bonds? 1 cellulose 2 glycogen 3 haemoglobin 4 water A 1, 2 and 3 only B 1, 2 and 4 only C 1, 3 and 4 only D 2, 3 and 4 only

Mark scheme: C

More questions on Water

12 Features of four proteins, W, X, Y and Z, are described below. W consists of two polypeptides held together by disulfide bonds X consists of three polypeptides tightly coiled together Y consists of four polypeptides each with a prosthetic group Z consists of four polypeptides held together by disulfide bonds Which row correctly identifies the named proteins? antibody collagen haemoglobin A W X Y B W Y X C Z X Y D Z Y X

Mark scheme: C

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13 Why may fish living in ponds survive temperatures below 0 °C in winter? A Fish body tissues produce an enzyme which prevents blood from freezing. B The ice on the pond surface insulates the water in the pond. C The plants in the pond help to keep the water temperature above 0 °C. D The rocks in the pond warm up during the day and heat the water.

Mark scheme: B

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14 Four students, 1, 2, 3 and 4, counted the number of bubbles of oxygen given off in a minute when investigating the effect of catalase from plant tissue on hydrogen peroxide. Each student repeated the experiment five times and calculated the mean number of bubbles per minute. Which have correctly calculated the mean? raw data / number of bubbles minute–1 mean / number of student bubbles minute-1 1 12 10 11 13 9 10.5 2 8 19 16 18 19 18 3 8 10 11 9 8 9 4 21 18 17 6 18 18.5 A 1 and 4 only B 2 and 3 only C 1, 2, 3 and 4 D 3 only

Mark scheme: B

More questions on Factors that affect enzyme action

15 The diagram shows a metabolic pathway. enzyme 1 enzyme 2 enzyme 3 reactant substance X substance Y end product What would be the effect of adding a small amount of a non-competitive inhibitor of enzyme 2? A Enzyme 2 would be partially denatured. B Substance X would increase in concentration. C Substance Y would no longer be formed. D The initial reactant would no longer be metabolised.

Mark scheme: B

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16 Which of the following can increase the fluidity of the cell surface membrane at low temperatures? 1 double bonds between carbon atoms in the fatty acid chains 2 cholesterol 3 fatty acids having shorter chains A 1, 2 and 3 B 1 and 3 only C 2 and 3 only D 1 only

Mark scheme: A

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17 Which process allows the movement of molecules that are too large to enter through a cell surface membrane? A active transport B endocytosis C exocytosis D facilitated diffusion

Mark scheme: B

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18 The diagram shows the water potential of three cells. cell X –700 kPa –800 kPa –1000 kPa In which directions will there be net movement of water by osmosis to or from cell X? A B C D

Mark scheme: B

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19 Which statement describes a cell belonging to a haploid organism that is capable of reproduction? A It has chromosomes that contain one polynucleotide chain. B It is capable of carrying out a reduction division to form gametes. C It possesses two copies of each gene as a result of fertilisation. D It will undergo cell division by mitosis during asexual reproduction.

Mark scheme: D

More questions on Replication and division of nuclei and cells

20 Some chemicals, used to stop tumour growth, work by preventing the DNA double helix from uncoiling and separating. During which stage of the cell cycle would they act? A anaphase B interphase C metaphase D prophase

Mark scheme: B

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21 Nocodazole is a chemical used in the study of mitosis. It causes all mitotic cells to stop dividing at metaphase. Which statements correctly identify how this chemical might work? 1 inhibits chromatin condensing in the nucleus 2 prevents replication of the centrioles 3 stops sister chromatids migrating to opposite poles A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 3 only

Mark scheme: D

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22 What is the maximum number of hydrogen bonds in a length of DNA containing 700 base pairs? A 350 B 700 C 1400 D 2100

Mark scheme: D

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23 Which type of molecule is always the end product of transcription? A amino acid B functional protein C mRNA D polypeptide

Mark scheme: C

More questions on Protein synthesis

24 The table gives tRNA anticodons for four amino acids. amino acid tRNA anticodon asparagine UUA glutamic acid CUU proline GGA threonine UGG A cell makes a polypeptide with the amino acid sequence: glutamic acid – asparagine – threonine – proline What was the sequence of bases on the strand of the DNA which was complementary to the mRNA from which this polypeptide was formed? A CTTTTATGGGGA B CUUUUAUGGGGA C GAAAATACCCCT D GAAAAUACCCCU

Mark scheme: A

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25 The diagram shows a xerophytic leaf in different conditions, P and Q. X X P Q Which statements about the cells in layer X of the leaf in each of the conditions P and Q are correct? 1 less negative water potential in P than Q 2 cells may be turgid in P and plasmolysed in Q 3 cells less turgid in P than Q 4 no net diffusion of water into X in either P or Q A 1, 2, 3 and 4 B 1, 2 and 4 only C 1 and 4 only D 2 and 3 only

Mark scheme: B

26 The loading of sucrose into companion cells involves a number of processes listed below. Which is an active process? A the movement of H+ ions from companion cells B the movement of H+ ions into companion cells C the movement of sucrose from companion cells D the movement of sucrose into companion cells

Mark scheme: A

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27 Which statement concerning transpiration is correct? A On a humid day, the water potential gradient between the intercellular air space and the external atmosphere increases to stimulate water loss by evaporation. B Water arriving at the spongy mesophyll cells via the symplast pathway must move by osmosis through the cell surface membrane before evaporation from the surface of the cells. C Water diffuses down the water potential gradient from the saturated air space through the guard cells before evaporating from the surface of the cells into the atmosphere. D Water moves up the xylem in the apoplast pathway and can continue on this pathway by osmosis to reach the spongy mesophyll cells before evaporating into the intercellular air space.

Mark scheme: B

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28 Halophytes are plants that can survive in regions where they are regularly exposed to sea water. Sea water has a water potential of approximately –2500 kPa. What adaptations would you expect halophytes to show? 1 root hair cells that maintain a more negative water potential than sea water 2 root hair cells that accumulate salts and other solutes 3 stomata that are open most of the time A 1 and 2 only B 1 and 3 only C 2 and 3 only D 1, 2 and 3

Mark scheme: A

29 Which features enable the aorta to withstand ventricular systole? A collagen fibres and elastin fibres B collagen fibres and smooth muscle C elastin fibres and endothelium D endothelium and smooth muscle

Mark scheme: A

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30 Haemoglobin can bind to carbon dioxide, carbon monoxide and oxygen. Which statement about the binding sites of haemoglobin is correct? A Carbon dioxide and carbon monoxide bind to one site, oxygen binds to a different site. B Carbon dioxide and oxygen bind to one site, carbon monoxide binds to a different site. C Carbon monoxide and oxygen bind to one site, carbon dioxide binds to a different site. D Carbon monoxide, oxygen and carbon dioxide all bind to different sites.

Mark scheme: C

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31 The diagram shows the pressure changes in various structures of the left side of the heart during the cardiac cycle. At the end of which period, A, B, C or D, is the ventricle full of blood? A B C D pressure key / kPa left ventricle aorta left atrium 0 0 0.2 0.4 0.6 0.8 time / s

Mark scheme: A

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32 Which substances will displace oxygen from oxyhaemoglobin? 1 carbon dioxide 2 carbon monoxide 3 hydrogen carbonate ions 4 hydrogen ions A 1 and 2 only B 1 and 4 only C 2 and 3 only D 2 and 4 only

Mark scheme: D

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33 Which statement about chronic obstructive pulmonary disease is not correct? A The disease can often be reversed by treatment. B The patient coughs a lot, bringing up mucus. C The patients are normally over 30 years old. D The patient’s symptoms normally do not change.

Mark scheme: A

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34 Which statement about coronary by-pass surgery is correct? A It is carried out to reduce the effects of atherosclerosis, improving the delivery of oxygen and dissolved glucose to the cardiac muscle of the heart. B It is the surgical removal of one or more coronary arteries to reduce the strain on the heart of a person with coronary heart disease. C Surgeons are able to divert blood around the diseased sections of the coronary arteries so that more oxygenated blood can be pumped round the systemic circulation. D The diseased parts of the aorta are replaced by using a section of a main artery from elsewhere in the body of the same person, to avoid rejection.

Mark scheme: A

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35 How does smoking increase the risk of developing atherosclerosis? A by damaging artery walls B by decreasing blood pressure C by increasing the risk of blood clotting D by reducing the oxygen supply to cardiac muscle

Mark scheme: A

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36 Which development in vaccine production would be most important in the fight to eradicate measles in developing countries? A a combined vaccine to combat it and other diseases B a single vaccine, without the need for boosters C a vaccine containing only live measles viruses D a vaccine produced by genetic engineering techniques

Mark scheme: B

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37 What could cause an outbreak of malaria in a country where it had been eliminated? 1 mosquitoes became resistant to insecticides 2 migration of population due to war 3 malarial parasites became resistant to quinine A 1 and 2 only B 1 and 3 only C 2 and 3 only D 1, 2 and 3

Mark scheme: D

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38 Termites are insects that build large nests that contain millions of termites of the same species. These nests are common in tropical savanna, which typically consists of grasses with widely spaced trees. Here, the termites feed on wood and other dead plant material. Which statement is correct? A The termites in the nest form a community, the savanna is the ecosystem and they feed as decomposers. B The termites in the nest form a community, the savanna is the ecosystem and they feed as primary consumers. C The termites in the nest form a population, the savanna is both the ecosystem and the habitat and they feed as primary consumers. D The termites in the nest form a population, the savanna is their habitat and they feed as decomposers.

Mark scheme: D

More questions on Biodiversity

39 During the nitrogen cycle, microorganisms are involved in nitrogen fixation, nitrification and denitrification. What are the correct soil conditions for each process? nitrogen fixation nitrification denitrification A aerobic aerobic anaerobic B aerobic anaerobic aerobic C anaerobic anaerobic aerobic D anaerobic aerobic anaerobic

Mark scheme: A

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40 Which processes are essential in making nitrogen in dead plant material available to growing plants? 1 ammonification 2 deamination 3 nitrification 4 nitrogen fixation A 1, 2 and 3 only B 1, 2 and 4 only C 1, 3 and 4 only D 2, 3 and 4 only

Mark scheme: A

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