Cambridge A Level Biology 9700 — 2018 May/June Paper 1 · Variant 1

Question 1

1 Which statements about resolution and magnification are correct? resolution magnification A the ability to distinguish between two the number of times larger an image is separate objects that are very close compared with the real size of the object together B the clarity of the image formed the power of the microscope to focus by the microscope on very small objects C the number of times larger an image is the ability to distinguish between two compared with the real size of the object separate objects that are very close together D the power of the microscope to focus the clarity of the image formed on very small objects by the microscope

Accepted Answer

A

Question 2

2 An eyepiece graticule has a scale with 100 divisions. A stage micrometer has a scale with 50 divisions, each of which is 0.040 mm apart. Using a ×40 objective lens, the whole length of this stage micrometer scale lines up with 15 divisions of the eyepiece graticule. What is the actual length of the 100 division scale of the eyepiece graticule? A 1.3 mm B 13 mm C 75 µm D 750 µm

Accepted Answer

B

Question 3

3 A prokaryotic cell which is 1 µm in diameter, is magnified 50 000 times in an electron micrograph. What is the diameter of the cell in the electron micrograph? A 5 × 10–1 mm B 5 × 100 mm C 5 × 101 mm D 5 × 102 mm

Accepted Answer

C

Question 4

4 A scientist carried out an experiment to separate cell structures in animal cells. The cells were broken open to release the cell structures. This extract was filtered into a centrifuge tube and then spun in a centrifuge. The heaviest cell structure sank to the bottom forming pellet 1, as shown in the diagram. liquid above pellet pellet 1 The liquid above pellet 1 was poured into a clean centrifuge tube and spun in the centrifuge at a higher speed to separate the next heaviest cell structure. This cell structure sank to the bottom, forming pellet 2. This procedure was repeated twice more to obtain pellet 3 and pellet 4, each containing a single type of cell structure. Which row shows the order in which the cell structures were collected? pellet 1 pellet 2 pellet 3 pellet 4 A nucleus lysosomes mitochondria ribosomes B nucleus mitochondria lysosomes ribosomes C ribosomes lysosomes mitochondria nucleus D ribosomes mitochondria lysosomes nucleus

Accepted Answer

B

Question 5

5 Radioactively-labelled nucleotides are introduced into a cell. 1 2 3 4 In which cell structures will the radioactivity first become concentrated? A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

Accepted Answer

C

Question 6

6 What is the general formula for amylose? A (C5H10O5)n B (C5H10O6)n C (C6H10O5)n D (C6H12O6)n

Accepted Answer

C

Question 7

7 The diagram shows relationships between some important molecules and bonds. 1 peptide glycosidic 3 ester 2 triglyceride cellulose vegetable oil amylopectin What is represented by circles numbered 1, 2 and 3? 1 2 3 A bonds formed carbohydrates lipids by condensation B bonds formed lipids carbohydrates by condensation C bonds formed carbohydrates lipids by hydrolysis D bonds formed lipids carbohydrates by hydrolysis

Accepted Answer

A

Question 8

8 In unsaturated lipid molecules, where are double bonds located? A between fatty acids and glycerol B within fatty acids and within glycerol C within fatty acids only D within glycerol only

Accepted Answer

C

Question 9

9 Phospholipids and triglycerides are important biological molecules. Which properties are correct for these molecules? non-polar partially hydrophobic A phospholipid phospholipid B phospholipid triglyceride C triglyceride phospholipid D triglyceride triglyceride

Accepted Answer

C

Question 10

10 The diagrams show two arrangements of amino acids in a protein. T S Which row correctly names the bonds at S or T? ionic bond hydrogen bond A absent S and T B S only T only C S and T absent D T only S and T

Accepted Answer

A

Question 11

11 Students were asked to highlight only the R groups of two ring-shaped amino acids. Which pair of diagrams are correct for both amino acids? H O H O H3N+ C C H2N+ C C A O– O– C NH H2C CH2 C CH2 C NH+ H O H O H3N+ C C H2N+ C C B O– O– C NH H2C CH2 C CH2 C NH+ H O H O H3N+ C C H2N+ C C C O– O– C NH H2C CH2 C CH2 C NH+ H O H O H3N+ C C H2N+ C C D O– O– C NH H2C CH2 C CH2 C NH+

Accepted Answer

D

Question 12

12 Which words from the table correctly complete the paragraph about enzymes? When the pH of an environment is decreased below the optimum pH of an enzyme, ««1«« bonds between adjacent ««2«« groups, holding the ««3«« structure, are disrupted. 1 2 3 A hydrogen and ionic R tertiary B hydrogen hydroxyl secondary C ionic and peptide R primary and tertiary D peptide amine primary

Accepted Answer

A

Question 13

13 The effect of substrate concentration on an enzyme-catalysed reaction was measured in three different conditions: ● with no inhibitor ● with a competitive inhibitor ● with a non-competitive inhibitor. The graph shows the results. enzyme with no inhibitor inhibitor X rate of reaction inhibitor Y 0 0 substrate concentration Which statement is correct? A X is a competitive inhibitor which binds to a site other than the active site of the enzyme. B X is a non-competitive inhibitor which has a similar shape to the active site of the enzyme. C Y is a competitive inhibitor which has a similar shape to the active site of the enzyme. D Y is a non-competitive inhibitor which binds to a site other than the active site of the enzyme.

Accepted Answer

D

Question 14

14 Which statements about the cell surface membrane are correct? 1 Channel proteins allow water soluble ions and molecules across the membrane. 2 Glucose can pass into the cell via carrier proteins. 3 Oxygen passes freely through the membrane as it is soluble in lipids. 4 Some glycoproteins act as antigens. A 1, 2, 3 and 4 B 1, 3 and 4 only C 1 and 2 only D 2, 3 and 4 only

Accepted Answer

A

Question 15

15 Which of these features increase the efficiency of ion uptake by a root hair cell? 1 many mitochondria in the cell 2 high concentration of ions in the vacuole 3 protein carriers in the cell surface membrane A 1, 2 and 3 B 1 and 3 only C 1 only D 2 and 3 only

Accepted Answer

B

Question 16

16 What 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 1 only D 2 and 3 only

Accepted Answer

A

Question 17

17 The diagrams show the shape and size of two types of cell. 50 μm 45 μm 10 μm 5 μm 10 μm 10 μm palisade mesophyll cell columnar epithelial cell surface area = 2200 μm2 volume = 2250 μm3 Which statement is correct about the palisade cell and epithelial cell shown in the diagrams? A An increase in surface area reduces the distance for gases to reach the centre of the cell. B The surface area of the palisade mesophyll cell is 500 µm2 greater than the columnar epithelial cell. C The surface area to volume ratio is greater in the columnar epithelial cell than the palisade mesophyll cell. D The volume of the palisade mesophyll cell is 2500 µm3 greater than that of the columnar epithelial cell.

Accepted Answer

C

Question 18

18 A student observed the cells in the growing region (meristem) of an onion root and obtained the data shown. stage number of cells interphase 886 prophase 73 metaphase 16 anaphase 14 telophase 11 Which percentage of cells contains chromosomes that appear as two chromatids? A 7.3 B 8.9 C 95.9 D 97.5

Accepted Answer

B

Question 19

19 Which of these events are part of mitosis? 1 interphase 2 telophase 3 cytokinesis A 1, 2 and 3 B 1 and 3 only C 1 only D 2 only

Accepted Answer

D

Question 20

20 During which phase of the cell cycle does DNA replication take place? A G1 B G2 C M D S

Accepted Answer

D

Question 21

21

Which row is correct for guanine?

has a joins its
double ring is a purine complementary base with
structure three hydrogen bonds
A WA J WA
B J x WA
Cc x Jv x
D x x JY

key
Y = correct
X = incorrect

Accepted Answer

A

Question 22

22 Meselsohn and Stahl investigated DNA in bacteria. They grew bacteria in a medium with only heavy nitrogen, 15N, until all of the bacterial DNA was heavy. These bacteria were moved from a heavy nitrogen medium and cultured in a medium with only light nitrogen, 14N. A sample of bacteria was collected from the first generation in the medium containing light nitrogen and their DNA was analysed. Hybrid DNA contains both heavy and light DNA. Which row shows the percentage of heavy DNA strands and the percentage of hybrid DNA molecules in the first generation produced in the medium containing light nitrogen? percentage of heavy percentage of hybrid DNA strands DNA molecules A 25 50 B 50 50 C 50 100 D 75 100

Accepted Answer

C

Question 23

23 Which is the correct DNA triplet on the original DNA template that codes for the amino acid histidine (His)? amino acid anticodon Ala CGU His GUA Ser UCA A CAU B CGT C GTA D GUA

Accepted Answer

C

Question 24

24 The photomicrograph shows tissues in a stained transverse section of a plant stem. Students are asked to draw four adjacent xylem vessel elements. Which drawing, all drawn to the same scale, is correct? A B C D

Accepted Answer

D

Question 25

25 What is a function of the hairs (trichomes) on xerophytic leaves? A adding a waterproof layer B protecting the stomata C reducing the surface area D trapping a layer of moist air

Accepted Answer

D

Question 26

26 Which features of companion cells are essential to their function? 1 They are connected by plasmadesmata to the sieve tube elements. 2 They have a thinner cell wall than a sieve tube element. 3 They contain a nucleus and mitochondria. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Accepted Answer

C

Question 27

27 The photomicrograph shows a human blood smear. 1 2 3 Which row identifies the labelled cells? 1 2 3 A lymphocyte monocyte neutrophil B lymphocyte neutrophil monocyte C monocyte lymphocyte neutrophil D monocyte neutrophil lymphocyte

Accepted Answer

D

Question 28

28 The diagram shows the changes in electrical activity in the heart muscle during one cardiac cycle. This is called an electrocardiograph (ECG). sinoatrial node stimulated stimulates ventricular systole Which electrocardiogram shows a rate of 75 beats per minute? A B 0 1 2 3 4 0 1 2 3 4 time / s time / s C D 0 1 2 3 4 0 1 2 3 4 time / s time / s

Accepted Answer

B

Question 29

29 Which effect could be due to a reduced concentration of carbonic anhydrase? A Carbaminohaemoglobin concentrations will decrease. B Less oxygen is released from oxyhaemoglobin for active tissues. C The pH of the blood will be lowered. D The rate of dissociation of carbonic acid is increased.

Accepted Answer

B

Question 30

30 Which statement correctly compares blood plasma and tissue fluid in a healthy person? A Blood plasma contains more protein than tissue fluid. B Both blood plasma and tissue fluid contain red blood cells. C Tissue fluid contains white blood cells whereas blood plasma does not. D Tissue fluid is formed from blood plasma and is not returned to blood plasma.

Accepted Answer

A

Question 31

31 The diagram shows three features found in tissues of the gas exchange system.

ciliated
epithelium

cartilage

Which tubes of the gas exchange system could be represented at position P in the diagram?

bronchus bronchiole trachea

v v v key
v= yes

0 Oo WwW >

J v x
Jv x Jv X =no
x v Jv

Accepted Answer

C

Question 32

32 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 structures labelled 1 to 6? contains high proportion of carbonic – ions HCO3 lysosomes anhydrase A 1 3 4 B 2 4 5 C 3 5 6 D 4 6 1

Accepted Answer

C

Question 33

33 A short-term effect of smoking is a decreased blood supply to the fingers and toes. Which component of cigarette smoke causes this effect? A carbon monoxide B carcinogens C nicotine D tar

Accepted Answer

C

Question 34

34 The symptoms of two diseases are listed. disease 1 disease 2 coughing up blood shortness of breath pain when breathing difficulty breathing out loss of weight fatigue Which row identifies diseases 1 and 2? disease 1 disease 2 A chronic bronchitis emphysema B emphysema lung cancer C lung cancer chronic bronchitis D lung cancer emphysema

Accepted Answer

D

Question 35

35 Which statements about a non-infectious disease may be correct? 1 It can result from a mutation. 2 It can be transmitted by an insect vector. 3 It can be transmitted from mother to child. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Accepted Answer

C

Question 36

36 The diagram shows one way of testing the effect of an antibiotic on bacteria. colonies of bacteria diameter of zone petri dish with measured every nutrient agar day for 5 days grown for containing 5 days bacteria disc of filter paper soaked in antibiotic The table shows the results of testing five different types of bacteria. Zones of less than 13.0 mm show the presence of resistant bacteria. type of diameter of zone / mm bacteria day 1 day 2 day 3 day 4 day 5 1 24.1 21.9 19.0 17.6 14.3 2 18.6 15.4 12.2 9.0 2.0 3 17.9 12.8 12.4 11.1 10.9 4 19.4 15.3 13.2 8.1 2.0 5 22.0 21.0 20.5 20.4 20.4 Which statement can be supported by this data? A All the types of bacteria become resistant to antibiotics over time. B Only types 2, 3 and 4 of the bacteria show resistance to the antibiotic. C The antibiotic can be used to treat types 1 and 3 only. D Type 5 of the bacteria can never become resistant to the antibiotic.

Accepted Answer

B

Question 37

37 Some animals have genes that code for small peptides called cathelicidins. These peptides kill a wide range of bacteria by attaching to lipids in bacterial membranes, so weakening or disrupting them. Scientists have produced a synthetic version of the cathelicidin that kills bacteria that are resistant to a number of antibiotics such as tetracycline. Which pair of statements explain how this synthetic cathelicidin might help with the problem of antibiotic resistance? 1 It is synthetic so bacteria can never become resistant to it. 2 It could be used instead of tetracycline, allowing tetracycline resistance to be reduced. 3 The only way a bacterium could develop resistance to it is by altering all the lipids in its membranes. 4 It could be used to kill multidrug-resistant strains of bacteria for which there is no effective antibiotic. A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Accepted Answer

D

Question 38

38 Hybridomas are used as a basis for the production of large numbers of monoclonal antibodies. Which statement describes how hybridomas are made? A fusing activated T-lymphocytes with cancer cells B fusing B-lymphocytes with cancer cells C fusing memory cells with cancer cells D fusing T-lymphocytes with cancer cells

Accepted Answer

B

Question 39

39 Which statement about the properties of the antigen binding sites in antibody molecules is correct? A They are located on the light chains only. B They have a hinge region to give flexibility for different antigens. C They have binding sites for receptors on phagocytes. D They have variable amino acid sequences for different antigens.

Accepted Answer

D

Question 40

40 The statements describe ways in which different types of monoclonal antibodies can work. 1 binding to proteins on cell surfaces and triggering the immune system 2 blocking molecules on cell surfaces that inhibit T-cells 3 blocking cell signalling receptors that trigger cell division 4 blocking cell signalling receptors that trigger the immune response Which types of monoclonal antibody could be used to treat cancer? A 1, 2, 3 and 4 B 1, 2 and 3 only C 1 and 4 only D 2, 3 and 4 only

Accepted Answer

B

Question paper20 pages

Mark scheme3 pages

Questions as text

Q1 · Which statements about resolution and magnification are correct?

Q2 · An eyepiece graticule has a scale with 100 divisions

Q3 · A prokaryotic cell which is 1 µm in diameter, is magnified 50 000 times in an electron…

Q4 · A scientist carried out an experiment to separate cell structures in animal cells

Q5 · Radioactively-labelled nucleotides are introduced into a cell

Q6 · What is the general formula for amylose?

Q7 · The diagram shows relationships between some important molecules and bonds

Q8 · In unsaturated lipid molecules, where are double bonds located?

Q9 · Phospholipids and triglycerides are important biological molecules

Q10 · The diagrams show two arrangements of amino acids in a protein

Q11 · Students were asked to highlight only the R groups of two ring-shaped amino acids

Q12 · Which words from the table correctly complete the paragraph about enzymes?

Q13 · The effect of substrate concentration on an enzyme-catalysed reaction was measured in…

Q14 · Which statements about the cell surface membrane are correct?

Q15 · Which of these features increase the efficiency of ion uptake by a root hair cell?

Q16 · What can increase the fluidity of the cell surface membrane at low temperatures?

Q17 · The diagrams show the shape and size of two types of cell

Q18 · A student observed the cells in the growing region (meristem) of an onion root and…

Q19 · Which of these events are part of mitosis?

Q20 · During which phase of the cell cycle does DNA replication take place?

Q21 · Which row is correct for guanine?

Q22 · Meselsohn and Stahl investigated DNA in bacteria

Q23 · Which is the correct DNA triplet on the original DNA template that codes for the amino…

Q24 · The photomicrograph shows tissues in a stained transverse section of a plant stem

Q25 · What is a function of the hairs (trichomes) on xerophytic leaves?

Q26 · Which features of companion cells are essential to their function?

Q27 · The photomicrograph shows a human blood smear

Q28 · The diagram shows the changes in electrical activity in the heart muscle during one…

Q29 · Which effect could be due to a reduced concentration of carbonic anhydrase?

Q30 · Which statement correctly compares blood plasma and tissue fluid in a healthy person?

Q31 · The diagram shows three features found in tissues of the gas exchange system

Q32 · The diagram shows a magnified section of part of the lungs containing specialised tissues

Q33 · A short-term effect of smoking is a decreased blood supply to the fingers and toes

Q34 · The symptoms of two diseases are listed

Q35 · Which statements about a non-infectious disease may be correct?

Q36 · The diagram shows one way of testing the effect of an antibiotic on bacteria

Q37 · Some animals have genes that code for small peptides called cathelicidins

Q38 · Hybridomas are used as a basis for the production of large numbers of monoclonal…

Q39 · Which statement about the properties of the antigen binding sites in antibody molecules…

Q40 · The statements describe ways in which different types of monoclonal antibodies can work

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