Cambridge A Level Biology 9700 — 2017 Oct/Nov Paper 1 · Variant 2

Question 1

1 Which equation for calculating the actual size of a specimen, A, or image size, I, or magnification, M, is correct? A A = M ÷ I B A = I × M C I = M ÷A D M = I ÷ A

Accepted Answer

D

Question 2

2 One of the smallest viruses is the polio virus, which has a diameter of approximately 30 nm. In 2003, the Mimivirus was discovered which has a diameter of approximately 680 nm. In 2013, the Pandoravirus was discovered which has a diameter of approximately 1000 nm. Which row correctly matches a cell structure with a virus that has a similar approximate size? polio virus Mimivirus Pandoravirus A lysosome nucleolus nucleus B nucleolus lysosome mitochondrion C nucleolus mitochondrion lysosome D ribosome lysosome mitochondrion

Accepted Answer

D

Question 3

3. Which cell components are present in all prokaryotic cells?

cell surface

endoplasmic

membrane cell wall reticulum flagellum
A JV V x y
B JV JV x x
Cc JV x W, x
D x JV W, y

key
/ = present

X = not present

Accepted Answer

B

Question 4

4 The electron micrograph shows part of an animal cell. What will be synthesised in large quantities in this cell? 1 ATP 2 glucose 3 RNA A 1, 2 and 3 B 1 and 3 only C 1 only D 2 only

Accepted Answer

B

Question 5

5 Mitochondria are thought to have evolved from prokaryotic cells that were ingested by an ancestral cell. Which feature have the prokaryotes lost during their evolution into mitochondria? A cell wall B circular chromosome C endoplasmic reticulum D ribosomes

Accepted Answer

A

Question 6

6 Which statement is correct? A A virus is composed of a protein coat which may surround RNA or DNA. B Eukaryotic plant cell walls contain peptidoglycans in addition to cellulose. C Plasmodesmata and centrioles are found in all plant cells. D Prokaryotic cells contain 80S ribosomes which they use to manufacture proteins.

Accepted Answer

A

Question 7

7 A student carried out four tests for biological molecules on a sample of milk. The tests and their results were as follows. ● Heating to 80 °C with Benedict’s solution gave a brick red colour. ● Adding Biuret solution gave a purple colour. ● Adding iodine solution gave an orange colour. ● Boiling with acid, followed by neutralisation, then heating to 80 °C with Benedict’s solution gave a brick red colour. Which biological molecules must be present in the milk? 1 non-reducing sugars 2 protein 3 reducing sugars 4 starch A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 3 and 4

Accepted Answer

C

Question 8

8 Which features adapt a cellulose molecule for its function? 1 Long chains of glucose molecules coil into a helix. 2 Many hydrogen bonds form between adjacent chains. 3 It is insoluble in water. A 1, 2 and 3 B 1 and 3 only C 2 and 3 only D 2 only

Accepted Answer

C

Question 9

9 Two disaccharides are maltose and sucrose. Maltose is formed from two molecules of glucose, whilst sucrose is formed from fructose and glucose. Which row shows the molecular formulae of the two disaccharides? maltose sucrose A C12H22O11 C12H22O11 B C12H22O11 C12H24O12 C C12H24O12 C12H22O11 D C12H24O12 C12H24O12

Accepted Answer

A

Question 10

10 The diagram shows the structure of the polysaccharide chitin which is found in the cell wall of fungi. CH3 C O CH2OH N H CH2OH H C O C C H H C O C C O C C O C C C C H H C O C C H N H CH2OH N H O C O C CH3 CH3 Which statements are correct for chitin and for cellulose? 1 The monomers are joined by 1,4 glycosidic bonds. 2 Every second monosaccharide in the polysaccharide chain is rotated by 180°. 3 The polysaccharide contains the elements carbon, hydrogen, oxygen and nitrogen. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Accepted Answer

B

Question 11

11 Which row correctly matches the functional and structural features of cellulose, collagen,

glycogen or triglyceride?

structure
molecules held
molecule function fibrous together by branched chains

hydrogen bonds
A cellulose support Jv Jv x
triglyceride energy source x x x
B collagen strengthening Jv Jv x
cellulose support Jv x Jv
Cc collagen strengthening Jv Jv Jv
glycogen storage x x Jv
D glycogen storage x Jv Jv
triglyceride | energy source x Jv x

key J=true

X = false

Accepted Answer

A

Question 12

12 A polypeptide has a number of amino acids (n). How many peptide bonds and R groups (side chains) does this polypeptide have? A n – 1 peptide bonds and n – 1 R groups B n – 1 peptide bonds and n R groups C n peptide bonds and n – 1 R groups D n peptide bonds and n R groups

Accepted Answer

B

Question 13

13 What are the features of triglycerides?

lower proportion

A Jv Jv x
B Jv x J
Cc x v x
D x x J

key
J/ = yes
X =no

Accepted Answer

C

Question 14

14 Which of these statements describe the action of an extracellular enzyme? 1 synthesis of a polynucleotide in the nucleus during DNA replication 2 digestion of macromolecules in the lumen of the small intestine 3 synthesis of ATP molecules in the mitochondria A 1 and 2 B 1 and 3 C 2 and 3 D 2 only

Accepted Answer

D

Question 15

15 An experiment was carried out in which the enzyme lipase was used to hydrolyse a triglyceride. The pH was recorded at regular intervals during the reaction. The results are shown in the table. time / minutes pH 0 7.0 2 6.2 4 5.6 6 5.1 8 4.7 10 4.6 12 4.6 14 4.6 At 14 minutes unreacted triglyceride was still present. What explains the results after 10 minutes? A The end-products acted as competitive inhibitors. B The end-products acted as non-competitive inhibitors. C The enzyme reaction had reached Vmax. D The tertiary structure of the enzyme had been lost.

Accepted Answer

D

Question 16

16 Which statement about the effect of substrate concentration on the activity of an enzyme is correct? A Above a certain concentration of substrate an enzyme reaches its maximum rate of reaction. B At high concentration of competitive inhibitor increasing the substrate concentration has no effect. C At high substrate concentration a non-competitive inhibitor no longer affects the enzyme activity. D The higher the concentration of substrate the faster an enzyme can catalyse a reaction.

Accepted Answer

A

Question 17

17 Which row shows a correct function of the components of the cell surface membrane? phospholipids cholesterol proteins glycoproteins A prevent the entry of regulates allow exchange allow cell-to-cell non-polar molecules permeability of the of ions communication membrane between the cell and its environment B prevent the entry of stabilises the allow cell-to-cell provide sites polar molecules membrane by communication of attachment binding to water for hormones molecules C regulate the prevents the entry allow exchange stabilise the flexibility of protons of gases membrane by of the cell between the cell and binding to water membrane its environment molecules D regulate the fluidity stabilises the form channels for allow cell-to-cell of the cell membrane over a polar molecules recognition membrane range of temperatures

Accepted Answer

D

Question 18

18 The graph shows how the rate of entry of substance X into a cell changes as the concentration of substance X outside the cell increases. rate of entry of substance X concentration of substance X outside the cell The diagram shows part of a cell surface membrane. 1 2 3 Which pathways could substance X use to enter the cell? A 1 and 2 B 1 only C 2 and 3 D 2 only

Accepted Answer

A

Question 19

19 The photomicrographs show cells in various stages of the cell cycle. In which stage does semi-conservative replication of DNA take place? A B C D

Accepted Answer

C

Question 20

20 The diagram shows the structure of one chromosome. 1 2 Which row is correct? number of 1 2 DNA strands A centromere chromatid 2 B centromere telomere 4 C chromatid telomere 2 D telomere chromatid 4

Accepted Answer

B

Question 21

21 Cancer cells may divide by far more divisions than other cells found in humans. Which statement about cancer cells is correct? A They are able to synthesise the enzyme telomerase. B They have a mutation in the telomeres so DNA is not hydrolysed. C They have DNA polymerase so can replicate their DNA without telomere loss. D They increase the number of copies of repeated DNA sequences in the telomeres.

Accepted Answer

A

Question 22

22 What is the maximum number of hydrogen bonds in a length of DNA containing 700 nucleotides? A 350 B 700 C 1050 D 2100

Accepted Answer

C

Question 23

23 Which statements concerning DNA and RNA are correct? 1 Adenine and guanine are bases that have a double ring structure; cytosine, thymine and uracil are bases with a single ring structure. 2 An adenine nucleotide from DNA is the same as an adenine nucleotide from RNA; DNA adenine pairs with thymine and RNA adenine pairs with uracil. 3 The base pairing that occurs in a double DNA helix and when RNA is synthesised during transcription is always according to the rule that a purine pairs with a pyrimidine. 4 The two polynucleotides on a DNA molecule run in opposite directions so that the double helix formed has two strands that are parallel to each other. A 1, 2 and 3 B 1, 2 and 4 C 1, 3 and 4 D 2, 3 and 4

Accepted Answer

C

Question 24

24 Two sets of bacteria were grown using different types of nitrogen-containing growth media. One set was grown in a medium containing the ‘heavy’ isotope of nitrogen, 15N, until all the DNA was labelled. The other set was grown in a medium containing the ‘light’ isotope of nitrogen, 14N, until all the DNA was labelled. The DNA from each set of bacteria was extracted and centrifuged. The diagram shows the position in the centrifuge tubes of this DNA. DNA with 14N DNA with 15N Bacteria with 15N labelled DNA were transferred to a medium containing 14N and allowed to reproduce once. The DNA of the new generation of bacteria was extracted and centrifuged. Which tube shows the position of DNA from this new generation of bacteria? A B C D

Accepted Answer

D

Question 25

25 The diagram shows the nucleotide sequence of a small section of a gene which is transcribed. GCGCGCGGCGCG The table shows the amino acids coded for by 10 mRNA codons. mRNA codon amino acid AAG Lys ACG Thr CGG  CGC  CGU Arg CCG Pro GCC  GCG Ala GGC Gly UGC Cys What is the order of the four amino acids in the polypeptide translated from this small section of a gene? A Ala-Ala-Cys-Ala B Ala-Arg-Gly-Ala C Arg-Ala-Pro-Arg D Arg-Arg-Thr-Arg

Accepted Answer

C

Question 26

26 What contributes to the movement of water through the xylem vessel elements? A cohesion of water molecules through hydrogen bonding B ion movement followed by passive osmosis C negative water potential in the xylem D surface tension at the top of the plant

Accepted Answer

A

Question 27

27 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

Accepted Answer

B

Question 28

28 What are features that adapt root hair cells for efficient uptake of mineral ions? 1 a large number of mitochondria 2 a large number of protein carriers in the cell surface membrane 3 a large surface area to volume ratio A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Accepted Answer

A

Question 29

29 The transverse sections of two plant organs are shown. S Q T R Which pair of tissues contains proton pumps? A Q and S B Q and T C R and S D R and T

Accepted Answer

C

Question 30

30 Measurements of the stem of a young tree showed that the diameter varied slightly. It decreased during the day and increased during the night. Which statement explains these observations? A During the day, cohesion between water molecules and lignin in the walls of the xylem vessels pulls the walls of the vessels inwards. B During the day, the tension developed in a moving column of water molecules reduces the pressure inside the xylem vessels, so that their walls move inwards. C During the night, the adhesion of water molecules to the lignin in the walls of the xylem vessels pushes the walls of the vessels outwards. D During the night, the pressure of the column of water molecules adhering to one another increases and pushes the walls of the xylem vessels outwards.

Accepted Answer

B

Question 31

31 Which statement about the human circulatory system is correct? A Blood passes twice through the heart in one complete circulation. B Blood, tissue fluid and lymph are all parts of the circulatory system. C Capillaries have the lowest blood pressure. D Veins in the circulatory system all carry deoxygenated blood.

Accepted Answer

A

Question 32

32 The graph shows changes in the volume of the ventricles during the cardiac cycle. P volume / arbitrary units R ventricular diastole atrial systole systole stages of the cardiac cycle Which valves open and close at P and R? atrioventricular semilunar valve valve at P at R A closes closes B closes opens C opens closes D opens opens

Accepted Answer

A

Question 33

33 Haemoglobin can bind to carbon dioxide, carbon monoxide and oxygen. 1 carbon dioxide 2 carbon monoxide 3 oxygen Which gases share a binding site? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Accepted Answer

D

Question 34

34 A good gas exchange system maintains a steep diffusion gradient, has a large total surface area and a short diffusion distance. Which feature of the human gas exchange system helps to maintain a steep diffusion gradient? A A large number of alveoli are present in each lung. B Alveoli walls contain elastic fibres allowing expansion. C The air brought into the alveoli by ventilation is high in oxygen. D The endothelium of the capillary wall is made of flattened cells.

Accepted Answer

C

Question 35

35 Which statement about bronchioles is correct? A They have cartilage and ciliated cells. B They have cartilage and elastic tissue. C They have cartilage and muscle tissue. D They have elastic tissue and ciliated cells.

Accepted Answer

D

Question 36

36 In which regions of the human gas exchange system is the function of some types of cell directly affected by tar in cigarette smoke? A bronchioles and alveoli only B trachea, bronchus, bronchioles, alveoli C trachea and bronchus only D trachea, bronchus and bronchioles only

Accepted Answer

D

Question 37

37 What is the causative agent and method of transmission of smallpox? method of causative agent transmission A Morbillivirus direct contact B Morbillivirus waterborne C Variola direct contact D Variola waterborne

Accepted Answer

C

Question 38

38 A scientist investigated the effect of an antibiotic on the treatment of cholera. 320 people suffering with cholera were split into two groups. One group was treated with an antibiotic while the other group was not given antibiotics. Both groups were given fluids containing sugars and mineral salts (oral rehydration therapy). The scientist recorded the number of days that each person suffered from diarrhoea. The table shows the results. mean time person had treatment diarrhoea / days antibiotic and oral rehydration therapy 3.2 oral rehydration therapy 5.3 What is the percentage decrease in the mean time that a person suffered from diarrhoea when they were treated with the antibiotic? A 39.6% B 60.4% C 165.6% D 252.4%

Accepted Answer

A

Question 39

39 Which sequence of events occurs during an immune response? 1 development of plasma cells 2 mitosis of B-lymphocytes 3 recognition of non-self antigens 4 secretion of antibodies A 2 → 3 → 4 → 1 B 2 → 4 → 3 → 1 C 3 → 1 → 2 → 4 D 3 → 2 → 1 → 4

Accepted Answer

D

Question 40

40 An influenza vaccine can be made by growing the viruses in chicken eggs. The viruses are extracted in liquid from the eggs and inactivated. The purified egg extract containing the viruses is then used as the vaccine. What is a side-effect of using this vaccine in some people? A An auto-immune condition could occur. B An immune response to egg antigens could occur. C The egg antigens could cause infections. D The influenza viruses could cause infections.

Accepted Answer

B

Question paper20 pages

Mark scheme3 pages

Questions as text

Q1 · Which equation for calculating the actual size of a specimen, A, or image size, I, or…

Q2 · One of the smallest viruses is the polio virus, which has a diameter of approximately 30…

Q3 · Which cell components are present in all prokaryotic cells?

Q4 · The electron micrograph shows part of an animal cell

Q5 · Mitochondria are thought to have evolved from prokaryotic cells that were ingested by an…

Q6 · Which statement is correct?

Q7 · A student carried out four tests for biological molecules on a sample of milk

Q8 · Which features adapt a cellulose molecule for its function?

Q9 · Two disaccharides are maltose and sucrose

Q10 · The diagram shows the structure of the polysaccharide chitin which is found in the cell…

Q11 · Which row correctly matches the functional and structural features of cellulose…

Q12 · A polypeptide has a number of amino acids (n)

Q13 · What are the features of triglycerides?

Q14 · Which of these statements describe the action of an extracellular enzyme?

Q15 · An experiment was carried out in which the enzyme lipase was used to hydrolyse a…

Q16 · Which statement about the effect of substrate concentration on the activity of an enzyme…

Q17 · Which row shows a correct function of the components of the cell surface membrane?

Q18 · The graph shows how the rate of entry of substance X into a cell changes as the…

Q19 · The photomicrographs show cells in various stages of the cell cycle

Q20 · The diagram shows the structure of one chromosome

Q21 · Cancer cells may divide by far more divisions than other cells found in humans

Q22 · What is the maximum number of hydrogen bonds in a length of DNA containing 700…

Q23 · Which statements concerning DNA and RNA are correct?

Q24 · Two sets of bacteria were grown using different types of nitrogen-containing growth media

Q25 · The diagram shows the nucleotide sequence of a small section of a gene which is…

Q26 · What contributes to the movement of water through the xylem vessel elements?

Q27 · The diagram shows a xerophytic leaf in different conditions, P and Q

Q28 · What are features that adapt root hair cells for efficient uptake of mineral ions?

Q29 · The transverse sections of two plant organs are shown

Q30 · Measurements of the stem of a young tree showed that the diameter varied slightly

Q31 · Which statement about the human circulatory system is correct?

Q32 · The graph shows changes in the volume of the ventricles during the cardiac cycle

Q33 · Haemoglobin can bind to carbon dioxide, carbon monoxide and oxygen

Q34 · A good gas exchange system maintains a steep diffusion gradient, has a large total…

Q35 · Which statement about bronchioles is correct?

Q36 · In which regions of the human gas exchange system is the function of some types of cell…

Q37 · What is the causative agent and method of transmission of smallpox?

Q38 · A scientist investigated the effect of an antibiotic on the treatment of cholera

Q39 · Which sequence of events occurs during an immune response?

Q40 · An influenza vaccine can be made by growing the viruses in chicken eggs

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