Cambridge A Level Biology 9700 — 2021 Oct/Nov Paper 1 · Variant 3

Question 1

1 A student was asked to use the scale bar shown to calculate the magnification of a cell on a photomicrograph. 2 μm Which method could the student use to calculate the magnification of the cell? A divide the diameter of the cell by the length of the scale bar, with both measured in the same units of length B measure the diameter of the cell in millimetres, multiply by 2000 and divide by the length of the scale bar measured in millimetres C measure the length of the scale bar in millimetres, convert to micrometres and divide by 2 D measure the length of the scale bar in millimetres, convert to micrometres and multiply by 2

Accepted Answer

C

Question 2

2 Which statements about light microscopy are always correct? 1 The greater the resolution of a light microscope, the greater the detail that can be seen. 2 The greater the magnification of a light microscope, the greater the detail that can be seen. 3 Increasing the magnification of a light microscope up to its limit of resolution allows more detail to be seen. 4 The shorter the wavelength of light used in a light microscope, the greater the detail that can be seen. A 1, 2, 3 and 4 B 1, 3 and 4 only C 1 and 2 only D 4 only

Accepted Answer

B

Question 3

3 What is the length of a typical prokaryote, such as the bacterium Escherichia coli ? A 1.5  101 nm B 1.5  102 nm C 1.5  100 m D 1.5  101 m

Accepted Answer

C

Question 4

4 Which cell structures are present in Plasmodium? B Golgi ribosomes body A C D mitochondria

Accepted Answer

A

Question 5

5 Which cell structures may contain nucleic acid? 1 cytoplasm 2 chloroplast 3 ribosome 4 Golgi body A 1, 2 and 3 B 1, 2 and 4 C 1, 3 and 4 D 2, 3 and 4

Accepted Answer

A

Question 6

6 Which row shows correct features of ATP? carbohydrate site of production of ATP in ATP A deoxyribose mitochondria and chloroplasts B pentose mitochondria and chloroplasts C hexose chloroplasts only D ribose mitochondria only

Accepted Answer

B

Question 7

7 Which tests will identify biological molecules that contain monomers with a carboxyl group? Benedict’s D A biuret ethanol C B

Question 8

8 Which polysaccharide is correctly described? polysaccharide monomer biological role A amylopectin -glucose storage molecule in animals B amylose -glucose storage molecule in plants C cellulose -glucose structural molecule in plants D glycogen -glucose structural molecule in animals

Accepted Answer

B

Question 9

9 Which formula represents a saturated fatty acid? A C18H36O2 B C18H34O2 C C18H32O2 D C18H30O2

Accepted Answer

A

Question 10

10 Which molecules always contain at least four double bonds? A triglyceride, collagen and haemoglobin B collagen and triglyceride only C haemoglobin and collagen only D triglyceride and haemoglobin only

Accepted Answer

C

Question 11

11 Which row about the structure of proteins is correct? primary structure secondary structure tertiary structure A the number the left-handed the result of of amino acids spiral formed by the cross-bonding between present in a protein primary structure specific amino acids in the primary structure B the order of the coiling of a the shape formed amino acids present chain of amino acids by folding of a in a protein to form a -pleated polypeptide and encoded by DNA sheet held together by hydrogen bonds C the result of occurs because of the result of ionic translation of an attraction between and hydrogen bonds, mRNA molecule by hydrogen and disulfide bridges a ribosome into a oxygen atoms in and hydrophobic chain of amino acids the side chains interactions between amino acids D the sequence formed by formed as a result of amino acids in hydrogen bonding of interaction of the a protein coded by between amino acids side chains of an mRNA molecule forming the amino acids in the primary structure primary structure

Accepted Answer

D

Question 12

12 Which statement about collagen is correct? A A collagen fibre is made of three parallel helices with hydrogen bonds holding them in place. B It is an insoluble fibrous protein with a quaternary structure. C One-third of the amino acids making up collagen are valine. D Collagen fibres are formed from several collagen molecules held together by ionic bonds.

Accepted Answer

B

Question 13

13 Which properties of water are the result of hydrogen bonding between water molecules? 1 solvent action 2 specific heat capacity 3 latent heat of vapourisation A 1 and 3 B 1 only C 2 and 3 D 2 only

Accepted Answer

C

Question 14

14 Which descriptions about all enzymes are correct? 1 catalyse the breakdown of large molecules into smaller molecules 2 only function inside cells 3 form temporary bonds with the substrate 4 have a tertiary structure A 1 and 2 B 1 and 3 C 2 and 3 D 3 and 4

Accepted Answer

D

Question 15

15 The cells in the roots of beetroot plants contain a red pigment. When pieces of root tissue are soaked in cold water, some of the red pigment leaks out of the cells into the water. An experiment was carried out to investigate the effect of temperature on the loss of red pigment from the root cells. It was found that the higher the temperature of the water, the higher the rate of loss of red pigment from the root cells. Which statements could explain this trend? 1 Enzymes in the cells denature as the temperature increases, so the pigment can no longer be used for reactions inside the cells and diffuses out. 2 As the temperature increases, the tertiary structure of protein molecules in the cell surface membrane changes, increasing the permeability of the membrane. 3 Phospholipid molecules gain kinetic energy as the temperature rises, increasing the fluidity of the phospholipid bilayer and allowing pigment molecules to diffuse out more easily. A 1 and 2 B 2 and 3 C 2 only D 3 only

Accepted Answer

B

Question 16

16 The diagram shows a partially plasmolysed plant cell. solution X Z solution Y What is found at Z? A air B solution X C solution Y D water

Accepted Answer

C

Question 17

17 A single-celled organism lives in freshwater. Water that enters the cytoplasm of the cell by osmosis is collected into a structure called the contractile vacuole. To remove the water the contractile vacuole fuses with the cell surface membrane. A student counted the number of times that the contractile vacuole filled and emptied when the cell was placed in solutions with different water potentials. The results are shown in the table. water potential of rate of contractile external solution vacuole emptying / kPa / min–1 0 31 –100 20 –200 13 –300 8 –400 6 –500 0 Which statement explains the pattern observed as the water potential of the external solution decreased? A The water potential gradient between the cell and the solution increased, causing water to move into the cell more rapidly and the contractile vacuole to empty more frequently. B The water potential gradient between the cell and the solution increased, causing water to move into the cell less rapidly and the contractile vacuole to empty less frequently. C The water potential gradient between the cell and the solution decreased, causing water to move into the cell more rapidly and the contractile vacuole to empty more frequently. D The water potential gradient between the cell and the solution decreased, causing water to move into the cell less rapidly and the contractile vacuole to empty less frequently.

Accepted Answer

D

Question 18

18 Which row shows the correct number of each component of a single chromatid during anaphase of mitosis? polynucleotide centromeres telomeres strands A 1 2 2 B 1 4 4 C 2 2 4 D 2 4 2

Accepted Answer

A

Question 19

19 Some processes are listed.  cytokinesis  differentiation  DNA replication  mitosis How many of the listed processes occur during tissue repair by stem cells? A 1 B 2 C 3 D 4

Accepted Answer

D

Question 20

20 The photomicrographs show cells in various stages of the cell cycle. Which stage of mitosis is not shown? A anaphase B prophase C metaphase D telophase

Accepted Answer

C

Question 21

21 Which letter in the key describes uracil? is a purine yes no is found has a single in RNA ring structure yes no yes no A B C D

Accepted Answer

C

Question 22

22 When a gene for protease is activated, which nucleic acid will be formed? A DNA B mRNA C rRNA D tRNA

Accepted Answer

B

Question 23

23 The diagram shows a vascular bundle from the stem of a plant. 3 2 1 Which row describes the functions of the labelled cells? transports transports stores sucrose mineral ions starch A 1 2 3 B 2 1 3 C 2 3 1 D 3 1 2

Accepted Answer

B

Question 24

24 Some of the features present in the transport tissues of plants are listed. 1 lignified walls 2 cytoplasm 3 mitochondria 4 chloroplasts 5 plasmodesmata Which features are present in sieve tube elements? A 1, 2 and 5 B 1, 3 and 4 C 2, 3 and 5 D 2, 4 and 5

Accepted Answer

C

Question 25

25 Which statements explain why transpiration is an inevitable consequence of gas exchange in plants? 1 Hydrolysis reactions are taking place in cells. 2 ATP production is occurring. 3 Stomata must be open. A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 3 only

Accepted Answer

D

Question 26

26 In an investigation, a leafy shoot was attached to a potometer and exposed to a variety of conditions. The time taken for the meniscus to move 50 mm along the capillary tubing was recorded for each set of conditions. time taken to temperature air humidity move 50 mm / C movement / s 20 dry not moving 125 20 dry moving 71 30 dry not moving 40 20 humid not moving 166 20 humid moving 83 30 humid not moving 55 Which row shows the slowest and fastest rates of water uptake for this investigation? slowest rate fastest rate / mm s–1 / mm s–1 A 0.3 1.3 B 0.3 3.3 C 3.3 0.3 D 1.3 0.8

Accepted Answer

A

Question 27

27 Proton pumps (H+ pumps) and co-transporters are used by plants when loading sucrose into a phloem sieve tube element at a source. Which row is correct? proton pump co-transporter A pumps protons into a the high concentration of protons in the companion cell raising its pH companion cell allows the transporter to be used for moving sucrose out of the cell B pumps protons into a the high concentration of protons in a mesophyll cell raising its pH mesophyll cell drives the transport of sucrose into the cell C pumps protons out of a the high concentration of protons outside companion cell into its cell wall a companion cell drives the transport of sucrose into the cell D pumps protons out of a the low concentration of protons in a mesophyll cell into its cell wall mesophyll cell allows the transporter to be used for moving sucrose out of the cell

Accepted Answer

C

Question 28

28 The statements list some of the events in the cardiac cycle. They are not in the correct order. 1 The impulse travels through Purkyne tissue. 2 A wave of excitation sweeps across the atria. 3 The atrioventricular node delays the impulse for a fraction of a second. 4 The sinoatrial node contracts. 5 The wave of excitation sweeps upwards from the base of the ventricles. 6 The ventricles contract. 7 The atria contract. Which statement describes the sixth of these events to occur in the cardiac cycle? A 1 B 3 C 4 D 5

Accepted Answer

D

Question 29

29 Which tissue types are present in the walls of all blood vessels? 1 collagen 2 elastic 3 endothelial 4 smooth muscle A 1, 2, 3 and 4 B 1, 2 and 4 only C 2 and 3 only D 3 only

Accepted Answer

D

Question 30

30 The photomicrograph shows three white blood cells labelled X, Y and Z. X Y Z Which row correctly identifies these cells? cell X cell Y cell Z A lymphocyte monocyte neutrophil B lymphocyte neutrophil monocyte C monocyte neutrophil lymphocyte D neutrophil monocyte lymphocyte

Accepted Answer

D

Question 31

31 When active tissues have high carbon dioxide concentrations, oxyhaemoglobin needs to release oxygen to the tissues. How is the carbon dioxide transported away by the blood from the tissues? 1 as carboxyhaemoglobin 2 as carbaminohaemoglobin 3 as hydrogencarbonate ions A 1, 2 and 3 B 1 and 3 only C 2 and 3 only D 2 only

Accepted Answer

C

Question 32

32 Which effect does increasing carbon dioxide concentration have on haemoglobin? A Haemoglobin is less efficient at taking up oxygen and less efficient at releasing oxygen. B Haemoglobin is less efficient at taking up oxygen and more efficient at releasing oxygen. C Haemoglobin is more efficient at taking up oxygen and less efficient at releasing oxygen. D Haemoglobin is more efficient at taking up oxygen and more efficient at releasing oxygen.

Accepted Answer

B

Question 33

33 The diagram shows a magnified section of part of the lungs containing specialised tissues. 1 2 3 4 5 6 Which row is correct for the structures labelled 1 to 6? contains high proportion of carbonic hydrogencarbonate lysosomes anhydrase ions A 1 3 4 B 2 4 5 C 3 5 6 D 4 6 1

Accepted Answer

C

Question 34

34 The table shows some parts of an animal’s lungs that contain different cell types.

cell type present

Partoflungs |) itiated | goblet smooin
trachea v v v
bronchus v v v
bronchiole v x v
alveoli x x x

key
/ = present

X = not present

Which parts of this animal’s lungs clean inhaled air and which carry out gas exchange?

clean inhaled air

gas exchange

0 0O WwW >

bronchiole and alveoli
bronchus and trachea only
bronchus and trachea only

bronchiole, bronchus, trachea

bronchus and trachea
bronchiole only
bronchiole and alveoli

alveoli only

Accepted Answer

D

Question 35

35 What helps to maintain a steep oxygen concentration gradient between the air in an alveolus and the blood? 1 Breathing in brings in a supply of air with a relatively high concentration of oxygen to the alveolus. 2 Blood flow brings blood with a relatively low concentration of oxygen to the alveolus. 3 The relatively low concentration of carbon dioxide in the alveolus results in the carbon dioxide leaving the red blood cell, allowing haemoglobin to combine with oxygen. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Accepted Answer

A

Question 36

36 Goblet cells are found in the trachea.

Which cell structures would be found extensively in a goblet cell?

Golgi body | mitochondria | ribosomes

v v v key

¥ = found extensively

00 WwW >

v v x
v Xx v X = not found extensively
x v v

Accepted Answer

A

Question 37

37 In a country where malaria has successfully been eliminated, an outbreak of malaria can occur years later. What could allow this later outbreak of malaria to occur? 1 mosquitoes become resistant to insecticides 2 migration of the population due to war 3 malarial parasites become resistant to quinine A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Accepted Answer

A

Question 38

38 Which row about a person with leukaemia only and about a person with measles only is correct? white blood cell bone marrow white blood cell count in a person function in a person count in a person with leukaemia only with leukaemia only with measles only A decreased increased decreased B decreased decreased increased C increased normal decreased D increased increased increased

Accepted Answer

D

Question 39

39 What is the cause of symptoms of people with myasthenia gravis? A antibodies block receptor molecules on the cell surface membrane of muscle cells B it is an autoimmune disease where self-antigens attack antibodies C the destruction of T-lymphocytes, which have receptors complementary to self-antigens D the loss of cell surface membrane receptors in nerve cells found in the spinal cord

Accepted Answer

A

Question 40

40 Tetanus is a bacterial infection. The graph shows the blood antibody concentration of two people. On day 0, person G was injected with antibodies to the tetanus toxin and person H was injected with the vaccine for tetanus. 25 G H 20 antibody 15 concentration / arbitrary units 10 5 0 0 5 10 15 20 time / days time of injection What could be the result if G and H were infected with the tetanus bacteria on day 20? A Tetanus antibodies would not be produced in person G. B Antibody production would peak after day 32 in person G. C Antibody concentration would stay constant in person H. D A second antibody peak would occur in person H that would be lower than the first peak.

Accepted Answer

B

Question paper20 pages

Mark scheme3 pages

Questions as text

Q1 · A student was asked to use the scale bar shown to calculate the magnification of a cell…

Q2 · Which statements about light microscopy are always correct?

Q3 · What is the length of a typical prokaryote, such as the bacterium Escherichia coli ?

Q4 · Which cell structures are present in Plasmodium?

Q5 · Which cell structures may contain nucleic acid?

Q6 · Which row shows correct features of ATP?

Q7 · Which tests will identify biological molecules that contain monomers with a carboxyl…

Q8 · Which polysaccharide is correctly described?

Q9 · Which formula represents a saturated fatty acid?

Q10 · Which molecules always contain at least four double bonds?

Q11 · Which row about the structure of proteins is correct?

Q12 · Which statement about collagen is correct?

Q13 · Which properties of water are the result of hydrogen bonding between water molecules?

Q14 · Which descriptions about all enzymes are correct?

Q15 · The cells in the roots of beetroot plants contain a red pigment

Q16 · The diagram shows a partially plasmolysed plant cell

Q17 · A single-celled organism lives in freshwater

Q18 · Which row shows the correct number of each component of a single chromatid during…

Q19 · Some processes are listed

Q20 · The photomicrographs show cells in various stages of the cell cycle

Q21 · Which letter in the key describes uracil?

Q22 · When a gene for protease is activated, which nucleic acid will be formed?

Q23 · The diagram shows a vascular bundle from the stem of a plant

Q24 · Some of the features present in the transport tissues of plants are listed

Q25 · Which statements explain why transpiration is an inevitable consequence of gas exchange…

Q26 · In an investigation, a leafy shoot was attached to a potometer and exposed to a variety…

Q27 · Proton pumps (H+ pumps) and co-transporters are used by plants when loading sucrose into…

Q28 · The statements list some of the events in the cardiac cycle

Q29 · Which tissue types are present in the walls of all blood vessels?

Q30 · The photomicrograph shows three white blood cells labelled X, Y and Z

Q31 · When active tissues have high carbon dioxide concentrations, oxyhaemoglobin needs to…

Q32 · Which effect does increasing carbon dioxide concentration have on haemoglobin?

Q33 · The diagram shows a magnified section of part of the lungs containing specialised tissues

Q34 · The table shows some parts of an animal’s lungs that contain different cell types

Q35 · What helps to maintain a steep oxygen concentration gradient between the air in an…

Q36 · Goblet cells are found in the trachea

Q37 · In a country where malaria has successfully been eliminated, an outbreak of malaria can…

Q38 · Which row about a person with leukaemia only and about a person with measles only is…

Q39 · What is the cause of symptoms of people with myasthenia gravis?

Q40 · Tetanus is a bacterial infection

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