Cambridge A Level Biology 9700 — 2017 Feb/March Paper 1 · Variant 2

Question 1

1 The diagram shows the ultrastructure of a typical animal cell. Which structure synthesises and transports lipids? D A B C

Accepted Answer

C

Question 2

2 A light microscope is used to observe two structures that are 200 nm apart. How far apart are the structures when the magnification is changed from ×40 to ×400? A 2 µm B 20 µm C 200 nm D 2000 nm

Accepted Answer

C

Question 3

3 The diagram shows a stage micrometer scale viewed through an eyepiece containing a graticule. The small divisions of the stage micrometer scale are 0.1 mm. 0 10 20 30 40 50 60 70 80 90 100 The stage micrometer scale is replaced by a slide of a plant cell. 0 10 20 30 40 50 60 70 80 90 100 What is the length of the nucleus in the plant cell? A 0.8 mm B 8 µm C 25 µm D 200 µm

Accepted Answer

C

Question 4

4 Some features of cells are listed. 1 cytoplasm 2 cell surface membrane 3 ribosomes Which features are found in both animal and prokaryotic cells? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Accepted Answer

A

Question 5

5 Which size of ribosomes is found in chloroplasts? A 60S B 70S C 80S D 90S

Accepted Answer

B

Question 6

6 In which of these organelles is ATP synthesised? Golgi body B A C mitochondrion D chloroplast

Accepted Answer

D

Question 7

7 A sample of milk is tested with Benedict’s solution. After boiling, a yellow colour is observed. Which conclusion is correct? A A high concentration of glucose is present. B A low concentration of sucrose is present. C No reducing sugars are present. D Reducing sugars are present.

Accepted Answer

D

Question 8

8 The table shows some information about carbohydrate polymers.

Which row describes amylose?

a-1,4

a-1,6

_ a shape of

glycosidic | glycosidic |  iolecule
bonds bonds

A W, JV branched

B V x helical

Cc x JV branched

D x x helical

key
/ = present
X = absent

Accepted Answer

B

Question 9

9 Which row about α-glucose and β-glucose molecules is correct? carbon atom on which cellulose contains both the OH position is different molecules A 1 no B 1 yes C 4 no D 4 yes

Accepted Answer

A

Question 10

10 Some of the molecules found in animal tissues are grouped into three lists. 1 glucose, cholesterol, triglycerides, water 2 glycogen, antibodies, adenine, phospholipids 3 haemoglobin, carbon dioxide, mRNA, monosaccharides Which lists include one or more molecules that always contain nitrogen atoms? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Accepted Answer

D

Question 11

11 Haemoglobin consists of two α chains and two β chains. Approximately 5% of all humans have one amino acid in the β chain that has been changed, affecting the structure and stability of haemoglobin. Which of the levels of protein structure could be changed in the haemoglobin of these humans? A primary only B primary and quaternary only C primary, secondary, tertiary and quaternary D secondary, tertiary and quaternary only

Accepted Answer

C

Question 12

12 Which row gives the correct description of both a collagen molecule and a collagen fibre? collagen molecule collagen fibre A α and β polypeptide chains molecules of collagen forming a double helix, held arranged randomly to each other, together by disulfide bonds linked by hydrogen bonds B a polypeptide chain, with repeating three molecules of collagen, amino acids, forming an α-helix forming a triple helix, held together by hydrogen bonds C a polypeptide chain, with three α helical collagen three repeating amino acids, molecules, forming a triple helix, forming a helix held together by ionic bonds D three helical polypeptide chains, molecules of collagen lying forming a triple helix, held parallel and cross-linked to each together by hydrogen bonds other

Accepted Answer

D

Question 13

13 The diagrams show the structures of two amino acids, each of which has two amine (–NH2) groups. 1 2 4 5 H2N CH COOH H2N CH COOH CH2 CH2 3 C CH2 O NH2 6 C O NH2 A peptide bond is formed between the two amino acids. Which groups could form the peptide bond? A 1 and 4 B 1 and 5 C 2 and 6 D 3 and 5

Accepted Answer

B

Question 14

14 An enzyme was added to a small excess of its substrate. All variables were kept constant. A student was asked to sketch a graph to show how the concentration of the enzyme-substrate complex changes over time. Which graph shows this correctly? A B concentration concentration 0 0 0 time 0 time C D concentration concentration 0 0 0 time 0 time

Accepted Answer

D

Question 15

15 The table contains results recorded by a student from an investigation into the effect of temperature on an enzyme-catalysed reaction. All other variables were standardised. rate of reaction temperature / °C / arbitrary units 10 3 20 7 30 16 40 33 50 32 60 14 What is the correct conclusion? A 40 °C was the optimum temperature. B The data for 50 °C was anomalous. C The optimum temperature was between 30 °C and 50 °C. D The optimum temperature was between 40 °C and 50 °C.

Accepted Answer

C

Question 16

16 What is the correct range of measurements for the width of the cell surface membrane? A 0.5–1.0 nm B 5–10 nm C 50–100 nm D 0.5–1 µm

Accepted Answer

B

Question 17

17 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 of these 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 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 18

18 The cell surface membrane structure is described as a ‘fluid mosaic’. Which statement describes the ‘mosaic’ part of the cell surface membrane? A the different patterns that are obtained by the moving phospholipid molecules B the random distribution of cholesterol molecules within the phospholipid bilayer C the regular pattern produced by the phospholipid heads and membrane proteins D the scattering of the different proteins within the phospholipid bilayer

Accepted Answer

D

Question 19

19 The diagram shows two pathways, X and Y, through which molecules can diffuse across a cell surface membrane. X Y Which row correctly shows possible pathways for lipids, water and glucose? lipids water glucose A X only X and Y Y only B X only Y only Y only C X and Y X only X and Y D X and Y X and Y X only

Accepted Answer

A

Question 20

20 Some stem cells divide and give rise to phagocytes. Where in the human body do these stem cells divide? 1 blood 2 bone marrow 3 lymph nodes A 1, 2 and 3 B 1 and 3 only C 2 only D 3 only

Accepted Answer

C

Question 21

21 What is the correct sequence of stages in the mitotic cell cycle? A G1 → G2 → mitosis → S → cytokinesis B G1 → G2 → S → mitosis → cytokinesis C G1 → S → G2 → mitosis → cytokinesis D S → G1 → mitosis → G2 → cytokinesis

Accepted Answer

C

Question 22

22 The enzyme telomerase repairs telomeres. It stops the telomeres from getting shorter each time a chromosome is replicated. Telomerase is not normally active in human body cells, but in some diseases telomerase can be activated. In which disease is the enzyme telomerase activated? A cancer B HIV/AIDS C malaria D myasthenia gravis

Accepted Answer

A

Question 23

23 The statements describe events during the mitotic cell cycle. 1 Chromosomes migrate to opposite poles of the spindle. 2 Chromosomes arrange themselves at the equator of the spindle. 3 Chromosomes condense and the nuclear membrane disappears. 4 Centromeres divide. What is the correct order of three of these events in the mitotic cell cycle? A 2 → 3 → 4 B 3 → 2 → 4 C 3 → 4 → 2 D 4 → 2 → 1

Accepted Answer

B

Question 24

24 Which statement about nitrogenous bases is correct? A Adenine is a pyrimidine with a double ring structure. B Cytosine is a purine with a double ring structure. C Guanine is a purine with a single ring structure. D Uracil is a pyrimidine with a single ring structure.

Accepted Answer

D

Question 25

25 Rifampicin is an antibiotic used to treat tuberculosis. It works by inhibiting RNA polymerase in bacteria. Which of these processes will be directly inhibited by this antibiotic? 1 ATP synthesis 2 transcription 3 translation A 1 and 2 B 1 and 3 C 2 only D 3 only

Accepted Answer

C

Question 26

26 Meselson and Stahl investigated DNA in bacteria. They grew bacteria in a medium with only heavy nitrogen, 15N, until all of the bacterial DNA contained only heavy nitrogen. These bacteria were then moved from the heavy nitrogen medium and cultured in a medium with only light nitrogen, 14N. Some bacteria were collected from each of the next three generations and their DNA was analysed. Hybrid DNA contains both heavy and light nitrogen. Which row shows the correct DNA of the first and third generations? DNA of first generation DNA of third generation A all hybrid half hybrid, half light B all hybrid one quarter hybrid, three quarters light C half hybrid, half heavy half hybrid, one quarter heavy, one quarter light D half hybrid, half light one quarter hybrid, three quarters light

Accepted Answer

B

Question 27

27 The diagram shows the stages in the production of part of a polypeptide. DNA nucleotide sequence template strand T A C G A C A A T C G C mRNA sequence A U G C U G U U A G C G amino acid sequence met     leu     leu      ala Which feature of the triplet code is illustrated by the information given? A An amino acid can be coded for by more than one triplet. B The triplet code is non-overlapping and is only read in one direction. C The triplet code is universal for the DNA of all organisms. D There are some triplets that code for ‘start’ and ‘stop’.

Accepted Answer

A

Question 28

28 Which combination of features is characteristic of a phloem sieve tube element as it unloads into a sink? lignification of water potential the cell wall A higher than sink absent B higher than sink present C lower than sink absent D lower than sink present

Accepted Answer

A

Question 29

29 Which statements correctly describe transport pathways in dicotyledonous plants? 1 In the symplast pathway, water may move through intercellular spaces. 2 The symplast pathway may be blocked by the tonoplast. 3 In the apoplast pathway, water does not move through plasmodesmata. 4 The apoplast pathway may be blocked by the Casparian strip. A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

Accepted Answer

D

Question 30

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

leaf

Which labelled structures transport mineral ions?

1 2 3 4
A Jv x v x key
B v x x v v/=yes
Cc x Jv J x xX =no
D x v x v

stem

Accepted Answer

A

Question 31

31 Which feature of transport in plants is correct for both xylem and phloem? A It is passive. B It occurs by mass flow. C It occurs from source to sink. D It occurs only in one direction.

Accepted Answer

B

Question 32

32 What is the main function of a companion cell in phloem tissue? A providing cytoplasmic contact with the sieve tube element for loading B providing structural support for the sieve tube element C providing the nucleus for cell division in the phloem D providing the source of assimilates for storage

Accepted Answer

A

Question 33

33 The contraction of the heart is coordinated through electrical impulses passing through the cardiac muscle. What is the correct order of part of the sequence of these impulses? A right and left atria → atrioventricular node → Purkyne tissue → ventricular walls B right and left atria → Purkyne tissue → ventricular walls → atrioventricular node C right and left atria → sinoatrial node → atrioventricular node → ventricular walls D sinoatrial node → right and left atria → Purkyne tissue → atrioventricular node

Accepted Answer

A

Question 34

34 As blood flows from an artery to a vein, the thickness of the walls of the vessels changes. Which bar chart shows these changes correctly? A B thickness thickness of wall of wall art a c v vn art a c v vn C D thickness thickness of wall of wall art a c v vn art a c v vn key art = artery a = arteriole (small artery) c = capillary v = venule (small vein) vn = vein

Accepted Answer

D

Question 35

35 The graph shows the oxygen dissociation curves of haemoglobin from two species of mammal, S and T. S percentage saturation of haemoglobin with oxygen T 00 partial pressure of oxygen / kPa Which statements could explain the difference in the oxygen dissociation curves of species S and species T? 1 Species T has a lower haemoglobin concentration in its red blood cells than species S. 2 The haemoglobin in species T has a lower affinity for oxygen than the haemoglobin in species S. 3 Species T lives at higher altitudes than species S. A 1, 2 and 3 B 1 and 2 only C 2 only D 3 only

Accepted Answer

C

Question 36

36 Which tissues may be found in bronchioles? A cartilage, ciliated epithelium, glandular tissue B ciliated epithelium, elastic fibres, smooth muscle C elastic fibres, cartilage, smooth muscle D smooth muscle, glandular tissue, cartilage

Accepted Answer

B

Question 37

37 Which of these statements could describe the effect of carbon monoxide in cigarette smoke? 1 It binds irreversibly to haemoglobin. 2 It causes mucus to accumulate in the bronchioles. 3 It results in more carbon dioxide being transported in the blood. 4 It temporarily increases the heart rate. A 1 and 2 B 1 only C 2 and 3 D 3 and 4

Accepted Answer

B

Question 38

38 The global mortality figures for some diseases in 2002 are shown in the table. cause of millions of percentage of death deaths all deaths HIV/AIDS 2.8 4.4 TB 1.6 2.7 malaria 1.3 2.2 measles 0.6 1.1 How many millions of people died from viral diseases listed in the table in 2002? A 2.2 B 3.4 C 3.8 D 4.4

Accepted Answer

B

Question 39

39 Which of the statements could describe both B-lymphocytes and T-lymphocytes? 1 They contain specific protein receptors in their cell surface membranes. 2 They differentiate into plasma cells. 3 They divide by mitosis. A 1 and 3 B 1 only C 2 and 3 D 2 only

Accepted Answer

A

Question 40

40 Two people, G and H, were each given an injection to protect them against a particular pathogen. One person was injected with antibodies. The other person was injected with a vaccine. The graph shows the concentrations of the antibody against this pathogen in the blood of the two people, G and H, over a period of 20 days following the injection. 25 H 20 G antibody 15 concentration / arbitrary units 10 5 0 0 5 10 15 20 time / days time of injection Which row correctly describes the type of immunity shown by G and H? G H A artificial active immunity artificial passive immunity B artificial passive immunity artificial active immunity C natural active immunity natural passive immunity D natural passive immunity artificial active immunity

Accepted Answer

B

Question paper20 pages

Mark scheme3 pages

Questions as text

Q1 · The diagram shows the ultrastructure of a typical animal cell

Q2 · A light microscope is used to observe two structures that are 200 nm apart

Q3 · The diagram shows a stage micrometer scale viewed through an eyepiece containing a…

Q4 · Some features of cells are listed

Q5 · Which size of ribosomes is found in chloroplasts?

Q6 · In which of these organelles is ATP synthesised?

Q7 · A sample of milk is tested with Benedict’s solution

Q8 · The table shows some information about carbohydrate polymers

Q9 · Which row about α-glucose and β-glucose molecules is correct?

Q10 · Some of the molecules found in animal tissues are grouped into three lists

Q11 · Haemoglobin consists of two α chains and two β chains

Q12 · Which row gives the correct description of both a collagen molecule and a collagen fibre?

Q13 · The diagrams show the structures of two amino acids, each of which has two amine (–NH2)…

Q14 · An enzyme was added to a small excess of its substrate

Q15 · The table contains results recorded by a student from an investigation into the effect of…

Q16 · What is the correct range of measurements for the width of the cell surface membrane?

Q17 · The cells in the roots of beetroot plants contain a red pigment

Q18 · The cell surface membrane structure is described as a ‘fluid mosaic’

Q19 · The diagram shows two pathways, X and Y, through which molecules can diffuse across a…

Q20 · Some stem cells divide and give rise to phagocytes

Q21 · What is the correct sequence of stages in the mitotic cell cycle?

Q22 · The enzyme telomerase repairs telomeres

Q23 · The statements describe events during the mitotic cell cycle

Q24 · Which statement about nitrogenous bases is correct?

Q25 · Rifampicin is an antibiotic used to treat tuberculosis

Q26 · Meselson and Stahl investigated DNA in bacteria

Q27 · The diagram shows the stages in the production of part of a polypeptide

Q28 · Which combination of features is characteristic of a phloem sieve tube element as it…

Q29 · Which statements correctly describe transport pathways in dicotyledonous plants?

Q30 · The diagrams show transverse sections of parts of a plant

Q31 · Which feature of transport in plants is correct for both xylem and phloem?

Q32 · What is the main function of a companion cell in phloem tissue?

Q33 · The contraction of the heart is coordinated through electrical impulses passing through…

Q34 · As blood flows from an artery to a vein, the thickness of the walls of the vessels changes

Q35 · The graph shows the oxygen dissociation curves of haemoglobin from two species of mammal…

Q36 · Which tissues may be found in bronchioles?

Q37 · Which of these statements could describe the effect of carbon monoxide in cigarette smoke?

Q38 · The global mortality figures for some diseases in 2002 are shown in the table

Q39 · Which of the statements could describe both B-lymphocytes and T-lymphocytes?

Q40 · Two people, G and H, were each given an injection to protect them against a particular…

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