Cambridge A Level Biology 9700 — 2019 May/June Paper 1 · Variant 2

Question 1

1 The actual length of a cell structure is 8 µm. Which steps are used to calculate the magnification of an electron micrograph of this cell structure? step 1 measure the length of the cell structure image on the micrograph in centimetres step 2 measure the length of the cell structure image on the micrograph in millimetres step 3 divide the image length by 1000 step 4 multiply the image length by 1000 step 5 divide by 8 step 6 multiply by 8 A steps 1, 3 and 6 B steps 1, 4 and 6 C steps 2, 3 and 5 D steps 2, 4 and 5

Accepted Answer

D

Question 2

2 What is the typical resolution of a microscope using daylight as a light source with a ×10 eyepiece lens and a ×40 objective lens? A 0.20 nm B 200 nm C 100 µm D 400 µm

Accepted Answer

B

Question 3

3 Two different types of cell, P and Q, were broken up using ultrasound and their contents analysed. Both types of cell contained small circular DNA. The circular DNA from P all carried the same base sequence, but those from Q were of two types, with different base sequences. What may be concluded about the identity of cell types P and Q? P Q A heart muscle fibres root cortical cells B lymphocytes mature red blood cells contaminated by bacteria C mature red blood cells phloem sieve tube element D root cortical cells leaf mesophyll cells

Accepted Answer

D

Question 4

4 Which features shown in the diagram can be present in viruses? 4 1 RNA DNA feature 3 2 70S protein coat ribosomes A 1, 2 and 3 B 1, 2 and 4 C 1, 3 and 4 D 2, 3 and 4

Accepted Answer

B

Question 5

5 After boiling a sample of milk with Benedict’s solution, a yellow colour is observed. Which conclusion about the sample of milk is correct? A Reducing sugars are not present. B Reducing sugars are present. C There is a high concentration of fructose. D There is a low concentration of sucrose.

Accepted Answer

B

Question 6

6 Which of the statements about polysaccharides can be used to describe amylose and cellulose? 1 contains 1,4 glycosidic bonds 2 contains 1,6 glycosidic bonds 3 polymer of glucose A 1 and 2 B 1 and 3 C 1 only D 2 and 3

Accepted Answer

B

Question 7

7 Which diagram shows the formation of a peptide bond? A B H H O H H O H H O O H H N C C N C C N C C C C N H H OH H H OH H H OH HO H H H2O H2O C D H H O H H O H H O O H H N C C N C C N C C C C N H H OH H H OH H H OH HO H H H2O H2O

Accepted Answer

A

Question 8

8

In enzyme-catalysed reactions, the position of the amino acids found at the active site is
important.

During the synthesis of enzymes, amino acids are brought together in the correct position to form
the active site.

Which levels of protein structure must be involved in forming the active site?

level of protein structure

primary | secondary tertiary quaternary

v v v v key
J = involved

X = not involved

0 OO WwW PY
x « &
S44
x KOK
\ <x

Accepted Answer

B

Question 9

9 Which features affect the tensile strength of collagen? 1 the helical structure of collagen chains 2 the small R group of the amino acids in collagen 3 the insoluble nature of collagen 4 the bonds between collagen molecules A 1, 2, 3 and 4 B 1, 2 and 4 only C 1 and 3 only D 2, 3 and 4 only

Accepted Answer

B

Question 10

10 A fixed volume of the enzyme catalase was added to a fixed volume of hydrogen peroxide solution. The diagram shows how the concentration of product changed over the course of the reaction. concentration of product 00 time What explains the shape of this graph? A The active sites become saturated. B The enzyme was denatured. C The hydrogen peroxide inhibited the reaction. D The substrate molecules were used up.

Accepted Answer

D

Question 11

11 A fixed volume and concentration of substrate and enzyme were mixed. All other variables were kept constant. The enzyme-catalysed reaction was left until it was complete. Which graph shows how the rate of reaction changes with time? A B rate of rate of reaction reaction 00 00 time time C D rate of rate of reaction reaction 00 00 time time

Accepted Answer

C

Question 12

12 The fatty acids elaidic acid and oleic acid have exactly the same structural formulae, with one double bond in the chain. However, the shapes of the chains are different, as shown in the diagram. elaidic acid oleic acid COOH COOH Which row shows the effect of the presence of these fatty acids on the structure and behaviour of a cell surface membrane? elaidic acid oleic acid A does not fit closely with other fits closely with other fatty fatty acids so that the membrane acids so that the membrane is is less fluid at high temperatures less fluid at low temperatures B does not fit closely with other fits closely with other fatty fatty acids so that the membrane acids so that the membrane is is more fluid at low temperatures less fluid at low temperatures C fits closely with other fatty does not fit closely with other acids so that the membrane is fatty acids so that the membrane less fluid at high temperatures is more fluid at low temperatures D fits closely with other fatty does not fit closely with other acids so that the membrane is fatty acids so that the membrane more fluid at low temperatures is more fluid at high temperatures

Accepted Answer

C

Question 13

13 The diagram shows a cell surface membrane. X Y W Z Which is a correct role for a labelled molecule? A W is involved in controlling membrane stability. B X is involved in active transport. C Y is involved in cell signalling. D Z is involved in diffusion of ions.

Accepted Answer

C

Question 14

14 The diagram shows a simple cell signalling pathway in which a signal molecule leads to a response, such as a secretion. signal → P → Q → response molecule Which row identifies P and Q? P Q A activated enzyme in cytoplasm target in cell surface membrane B lipid in cell surface membrane extracellular enzyme C protein in cell surface membrane activated enzyme in cytoplasm D target in cytoplasm protein in cell surface membrane

Accepted Answer

C

Question 15

15 Three parts of a chromosome and their functions are listed. part function P1 centromere F1 holds the coils of DNA together P2 histone proteins F2 holds two chromatids together P3 telomere F3 prevents loss of genes Which part is matched with its correct function? A P1 and F1 B P2 and F1 C P2 and F3 D P3 and F2

Accepted Answer

B

Question 16

16 The enzyme telomerase prevents loss of telomeres after many mitotic cell cycles. Which cells need to transcribe telomerase enzyme? 1 cancer cells 2 stem cells 3 activated memory B-lymphocytes A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Accepted Answer

A

Question 17

17 The diagram shows some of the stages which take place during the cell cycle. 1 number of DNA molecules in cell doubles 4 stages 2 nuclear envelope during cell cell grows disappears cycle 3 chromosomes become visible Which two stages take place during interphase? A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Accepted Answer

A

Question 18

18 Which statement correctly describes the base pairing in a molecule of DNA? A The purine adenine forms bonds with the pyrimidine thymine. B The purine adenine forms bonds with the pyrimidine uracil. C The purine cytosine forms bonds with the pyrimidine guanine. D The purine guanine forms bonds with the pyrimidine thymine.

Accepted Answer

A

Question 19

19 Which statements about complementary base pairing are correct? 1 It allows translation to occur. 2 Purines and pyrimidines are the same size. 3 The base pairs are of equal length. 4 Uracil forms two hydrogen bonds with adenine. A 1, 2, 3 and 4 B 1, 3 and 4 only C 1 and 4 only D 2 and 3 only

Accepted Answer

B

Question 20

20 The diagram shows the possible organisation of DNA molecules after one replication. Which organisation is correct? one strand of DNA A B C D

Accepted Answer

C

Question 21

21 The diagram shows part of the DNA sequence of a gene and a mutated sequence of the same gene. normal DNA sequence ... CCG GAT TAT TGC GAG AAA TGG CAT TCT AGG ... mutated DNA sequence ... CCG GAT GTA TTG CGA GAA ATG CAT TCT AGG ... What are possible effects of the mutated sequence? 1 the presence of mRNA stop codons, UAG, UAA or UGA 2 a change in the sequence of amino acids 3 a non-functional protein 4 ribosomes cannot translate the mRNA A 1, 2 and 3 B 1, 3 and 4 C 1 and 4 only D 2 and 3 only

Accepted Answer

D

Question 22

22 What is correct for phloem sieve tube elements? A Companion cells provide structural support to the phloem sieve tube elements. B Lignified walls of phloem sieve tube elements prevent transport of mineral salts by mass flow. C Phloem sieve tube elements become narrower as movement of sucrose occurs. D Plasmodesmata allow movement of water and solutes across cell walls of phloem sieve tube elements.

Accepted Answer

D

Question 23

23 The diagrams show transverse sections of parts of a plant.

Transport tissues are labelled 1 to 6.

leaf stem root

Which combination shows the tissues that have a main function of transporting water?

Accepted Answer

B

Question 24

24 The statements are descriptions of how water moves across the root to the xylem vessel elements. 1 Water enters cell walls. 2 Water enters cytoplasm by osmosis. 3 Water moves from cell to cell through plasmodesmata. 4 Water moves through cell walls. Which statements describe the apoplast pathway? A 1, 2, 3 and 4 B 1, 2 and 3 only C 1 and 4 only D 4 only

Accepted Answer

C

Question 25

25 Four plants, A, B, C and D, were grown in the same conditions and their transpiration rates measured. Which plant is most likely to be a xerophyte? transpiration A rate / mg cm–2 B C D 00:00 12:00 24:00 time of day / hours

Accepted Answer

D

Question 26

26 Sucrose moves from a mesophyll cell in a leaf into a phloem sieve tube element. Which changes to the water potential and the volume of liquid in the phloem sieve tube element are correct? water potential volume of liquid becomes A less negative decreases B less negative increases C more negative decreases D more negative increases

Accepted Answer

D

Question 27

27 The diagram shows a cross-section through a mammalian heart. W X Which chambers of the heart are represented by W and X? W X A left ventricle right ventricle B right atrium left atrium C right atrium right ventricle D right ventricle left ventricle

Accepted Answer

D

Question 28

28 At a certain point in a cardiac cycle, the pressure in the right ventricle is lower than that in the right atrium and lower than that in the pulmonary artery. Which row is correct? atrioventricular semilunar valve valve A closed closed B closed open C open closed D open open

Accepted Answer

C

Question 29

29 The diagram shows the pathway for the transport of carbon dioxide that occurs in red blood cells. CO2 1 H2O 2 haemoglobin 3 4 Which row is correct? 1 2 3 4 A carbaminohaemoglobin haemoglobinic hydrogen ions hydrogencarbonate acid ions B carbonic anhydrase carbonic acid hydrogen ions hydrogencarbonate ions C carboxyhaemoglobin carbonic carbonic acid carbon dioxide anhydrase D haemoglobinic acid carbonic acid hydrogencarbonate hydrogen ions ions

Accepted Answer

B

Question 30

30 The diagram shows a transverse section through an artery. X Which statement describes the tissues present in layer X? A collagen and smooth muscle only B elastic fibres and collagen only C elastic fibres and smooth muscle only D elastic fibres, collagen and smooth muscle

Accepted Answer

D

Question 31

31 The large arteries close to the heart have a thick elastic layer in their walls. Which statements about this layer are correct? 1 helps to maintain the blood pressure in arteries 2 reduces friction within the arteries 3 prevents too much pressure bursting the artery wall A 1, 2 and 3 B 1 and 3 only C 1 only D 2 and 3 only

Accepted Answer

B

Question 32

32 Which tissues are present in the walls of a trachea and an alveolus?

tissue
epithelium with
goblet cells

A trachea Jv
alveolus x

B trachea Jv
alveolus x

Cc trachea Jv
alveolus v

D trachea x
x

alveolus

smooth
muscle

<<

KK

key

v¥ = present
X = absent

Accepted Answer

A

Question 33

33 The surface tension of the layer of liquid lining the alveoli tends to pull the walls inwards so alveoli could collapse. Which statements could explain how this is prevented? 1 Alveolar fluid is moved around by cilia. 2 Elastic fibres keep the alveoli open. 3 Epithelial cells secrete a chemical that reduces the cohesion in water. A 1 and 2 B 1 and 3 C 2 and 3 D 3 only

Accepted Answer

D

Question 34

34 The diagram shows some of the effects of nicotine and carbon monoxide in cigarette smoke. 2 3 1 carbon nicotine monoxide Which row is correct? 1 2 3 A increase in heart rate short-term effect on combines more readily with cardiovascular system haemoglobin than oxygen B increases diameter can cause combines irreversibly of small arteries chronic bronchitis with haemoglobin C reduces the oxygen short-term effect on reduces the blood carrying capacity of blood gas exchange system supply to hands and feet D stimulates goblet cells highly addictive increases risk to secrete more mucus of blood clotting

Accepted Answer

A

Question 35

35 Which row correctly identifies the causative organism of each disease? cholera measles smallpox tuberculosis A Variola Morbillivirus Vibrio Mycobacterium B Variola Mycobacterium Vibrio Morbillivirus C Vibrio Morbillivirus Variola Mycobacterium D Vibrio Mycobacterium Variola Morbillivirus

Accepted Answer

C

Question 36

36 The following advice was given to a person travelling to a country where there had been an outbreak of an infectious disease. ● cook food well and eat it hot ● peel fruit and vegetables ● drink only cool, boiled water ● wash hands often with soap and cool, boiled water Which infectious disease would this advice help to protect against? A cholera B malaria C measles D tuberculosis

Accepted Answer

A

Question 37

37 What is a social factor that affects the spread of malaria? A an increase in drug resistant forms of malaria B climate change C difficulty in producing a vaccine D migration of people because of wars

Accepted Answer

D

Question 38

38 Which are specific immune responses? 1 phagocytosis 2 production of antibodies 3 production of memory cells A 1 and 3 only B 1 only C 2 and 3 only D 2 only

Accepted Answer

C

Question 39

39 Newborn babies have natural passive immunity.

What is correct for this type of immunity?

immunity is antibodies are
temporary broken down
A Jv Jv key
B v x ¥ = correct
Cc x v X = not correct
D x x

Accepted Answer

A

Question 40

40 The diagrams show three different types of antibody structure. IgG IgA IgM Which row is correct? IgG IgA IgM A one binding site for two light chains two heavy chains an antigen molecule B two heavy chains four binding sites five hinge regions for antigen molecules C two hinge regions four heavy chains five light chains D two light chains four hinge regions ten binding sites for antigen molecules

Accepted Answer

B

Question paper20 pages

Mark scheme3 pages

Questions as text

Q1 · The actual length of a cell structure is 8 µm

Q2 · What is the typical resolution of a microscope using daylight as a light source with a…

Q3 · Two different types of cell, P and Q, were broken up using ultrasound and their contents…

Q4 · Which features shown in the diagram can be present in viruses?

Q5 · After boiling a sample of milk with Benedict’s solution, a yellow colour is observed

Q6 · Which of the statements about polysaccharides can be used to describe amylose and…

Q7 · Which diagram shows the formation of a peptide bond?

Q8 · In enzyme-catalysed reactions, the position of the amino acids found at the active site…

Q9 · Which features affect the tensile strength of collagen?

Q10 · A fixed volume of the enzyme catalase was added to a fixed volume of hydrogen peroxide…

Q11 · A fixed volume and concentration of substrate and enzyme were mixed

Q12 · The fatty acids elaidic acid and oleic acid have exactly the same structural formulae…

Q13 · The diagram shows a cell surface membrane

Q14 · The diagram shows a simple cell signalling pathway in which a signal molecule leads to a…

Q15 · Three parts of a chromosome and their functions are listed

Q16 · The enzyme telomerase prevents loss of telomeres after many mitotic cell cycles

Q17 · The diagram shows some of the stages which take place during the cell cycle

Q18 · Which statement correctly describes the base pairing in a molecule of DNA?

Q19 · Which statements about complementary base pairing are correct?

Q20 · The diagram shows the possible organisation of DNA molecules after one replication

Q21 · The diagram shows part of the DNA sequence of a gene and a mutated sequence of the same…

Q22 · What is correct for phloem sieve tube elements?

Q23 · The diagrams show transverse sections of parts of a plant

Q24 · The statements are descriptions of how water moves across the root to the xylem vessel…

Q25 · Four plants, A, B, C and D, were grown in the same conditions and their transpiration…

Q26 · Sucrose moves from a mesophyll cell in a leaf into a phloem sieve tube element

Q27 · The diagram shows a cross-section through a mammalian heart

Q28 · At a certain point in a cardiac cycle, the pressure in the right ventricle is lower than…

Q29 · The diagram shows the pathway for the transport of carbon dioxide that occurs in red…

Q30 · The diagram shows a transverse section through an artery

Q31 · The large arteries close to the heart have a thick elastic layer in their walls

Q32 · Which tissues are present in the walls of a trachea and an alveolus?

Q33 · The surface tension of the layer of liquid lining the alveoli tends to pull the walls…

Q34 · The diagram shows some of the effects of nicotine and carbon monoxide in cigarette smoke

Q35 · Which row correctly identifies the causative organism of each disease?

Q36 · The following advice was given to a person travelling to a country where there had been…

Q37 · What is a social factor that affects the spread of malaria?

Q38 · Which are specific immune responses?

Q39 · Newborn babies have natural passive immunity

Q40 · The diagrams show three different types of antibody structure

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