Cambridge A Level Biology 9700 — 2025 May/June Paper 1 · Variant 4

Question 1

1 Plant cells are stained and then viewed with a simple light microscope, using daylight as the only light source. Which cell structures are clearly visible at a magnification of  400? A chloroplast grana B lysosomes C nucleoli D ribosomes

Accepted Answer

C

Question 2

2 The diagram shows an image of a cell with a scale bar. The scale bar (Z) represents an actual size of 15 m. Distance Y represents the diameter of the cell image. Y Z Which calculation to find the actual diameter of the cell is correct? A 15  (Y + Z)  Z  B Y     15   Y  C    15  Z   Y  D    15 

Accepted Answer

C

Question 3

3 The diagram shows a stage micrometer, with divisions of 0.1 mm, viewed using an eyepiece graticule. 0 10 20 30 40 50 60 70 80 90 100 Pollen grains were grown in a sugar solution and viewed using the eyepiece graticule. Diagram 1 shows the pollen grains at the start. Diagram 2 shows the pollen grains after 4 hours. diagram 1 diagram 2 pollen tube 0 10 20 30 40 50 60 70 80 90 100 0 10 20 30 40 50 60 70 80 90 100 at start after 4 hours What is the growth rate of the pollen tubes? A 5 m h–1 B 10 m h–1 C 5 mm h–1 D 10 mm h–1

Accepted Answer

A

Question 4

4 What are found in chloroplasts and also in mitochondria? 1 DNA 2 70S ribosomes 3 mRNA A 1, 2 and 3 B 1 and 2 only C 1 only D 2 and 3 only

Accepted Answer

A

Question 5

5 A long-distance runner has become adapted to run faster for longer after regular training. Which cell structure in a muscle cell has increased in number to allow this adaptation? A lysosome B mitochondrion C nucleus D smooth endoplasmic reticulum

Accepted Answer

B

Question 6

6 Some functions carried out within eukaryotic cells are listed. 1 lysosome production 2 polypeptide modification 3 exocytosis Which functions are carried out by the Golgi body? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Accepted Answer

B

Question 7

7 The diagram shows the structure of a unicellular organism. nucleus mitochondria cell membrane vacuole cytoplasm Which statement is correct for this organism? A It contains a nucleus so it is not prokaryotic. B It contains mitochondria so it is not a plant. C It does not have a cell wall so it must be eukaryotic. D It is unicellular so it must be a bacterium.

Accepted Answer

A

Question 8

8 Diastase is an enzyme that breaks down starch into maltose. A sample of starch is treated with boiled diastase and left for 15 minutes. Samples of the mixture are then tested with iodine solution and with Benedict’s solution. What is the correct result? iodine solution Benedict’s solution A blue-black blue B blue-black red C brown blue D brown red

Accepted Answer

A

Question 9

9 Which molecule is required for this reaction to occur? C12H22O11  +  H2O    C6H12O6  +  C6H12O6 A catalase B copper sulfate C hydrochloric acid D sodium hydroxide

Accepted Answer

C

Question 10

10 Which molecules contain at least two double bonds? unsaturated fatty acid C A D collagen haemoglobin B

Accepted Answer

D

Question 11

11 Which description of globular proteins is correct? A They are only found in cell surface membranes. B They only contain amino acids with hydrophilic R groups. C They can change shape by using energy from ATP. D They always have a quaternary structure of at least three polypeptides.

Accepted Answer

C

Question 12

12 Which diagram shows where a hydrogen bond occurs between two water molecules? A B δ– δ– O O δ+ δ+ δ+ δ+ H H H H δ– δ+ δ+ O H H δ+ δ+ H H O δ– key C D hydrogen bond δ+ δ+ O O δ– δ– δ– δ– H H H H δ– δ– δ+ H H O δ– δ– O H H δ+

Accepted Answer

A

Question 13

13 Some detergents disrupt hydrogen bonds between water molecules. Which row shows the correct effects of detergent on the specific heat capacity and latent heat of vaporisation of water? specific heat latent heat of capacity vaporisation A decreases decreases B decreases increases C increases decreases D increases increases

Accepted Answer

A

Question 14

14 An investigation was carried out to see if compound X could improve the thermostability of an
enzyme. Thermostable enzymes will function well at high temperatures.

The results of the investigation are shown.

120

100

80
enzyme ‘ xperiment 2
activity 60 experiment 1——--*s without compound -X
I% with compound XC
40

©

20 ‘

@) =
10 20 30 40 50 60 70

temperature /°C

Which row is correct?

compound X makes the
enzyme more
thermostable

at 40°C in experiment 1
most of the enzyme
active sites will no longer
be complementary to the

at 45°C in experiment 2
approximately half of the
enzymes are forming
enzyme-—substrate

substrate complexes
A Jv x x
B Jv v x
Cc x v v
D x x v
key
¥ = correct

X = not correct

Accepted Answer

C

Question 15

15 The table shows the results 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 All the enzymes denatured at 60 °C.

Accepted Answer

C

Question 16

16 The graph shows how the rate of a reaction changes with substrate concentration in the presence of:  no inhibitor  inhibitor X  inhibitor Y. One of the inhibitors is competitive and the other inhibitor is non-competitive. 0.006 0.005 no enzyme inhibitor no enzyme inhibitor no enzyme inhibitor 0.004 with inhibitor X with inhibitor X with inhibitor X rate of reaction 0.003 / mol dm–3 s–1 0.002 with inhibitor Y with inhibitor Y with inhibitor Y 0.001 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 substrate concentration / mol dm–3 What is the correct estimate of Km for the reaction shown when a competitive inhibitor is present? A 0.11 mol dm–3 B 0.23 mol dm–3 C 0.38 mol dm–3 D 0.65 mol dm–3

Accepted Answer

B

Question 17

17 Which of these substances can pass directly through cell surface membranes without using a carrier protein or channel protein? 1 K+ and Cl – 2 CO2 3 C6H12O6 A 1 and 2 B 1 and 3 C 2 and 3 D 2 only

Accepted Answer

D

Question 18

18 Which of these statements about facilitated diffusion are correct? 1 It is limited by the number of transport proteins. 2 It transports molecules against their concentration gradient. 3 It requires a source of ATP. A 1, 2 and 3 B 1 and 3 only C 1 only D 2 and 3 only

Accepted Answer

C

Question 19

19 A cell absorbs amino acids. This cell then synthesises and exports a digestive enzyme. Different cell structures are involved with different stages of this process. Which row shows a possible sequence of cell structures that the amino acids pass through? rough cell surface secretory Golgi body endoplasmic membrane vesicle reticulum A 1st 2nd 3rd 4th B 1st 3rd 4th 2nd C 4th 2nd 1st 3rd D 4th 1st 2nd 3rd

Accepted Answer

C

Question 20

20 The diagram shows apparatus set up to investigate the effect of changing the initial concentration of glucose in the surrounding solution on the movement of molecules through a selectively permeable membrane (Visking tubing) in 15 minutes. Visking tubing surrounding solution (different concentrations 10% glucose from 1% to 10% solution glucose solution) Which statements are correct as the initial concentration of glucose solution in the surrounding solution increases? 1 Net diffusion of water increases. 2 Glucose molecules reach an equilibrium quicker. 3 There is less change in the volume of the surrounding solution. 4 Net diffusion of glucose increases. A 1, 2, 3 and 4 B 1, 2 and 4 only C 1 and 3 only D 2 and 3 only

Accepted Answer

D

Question 21

21 The epithelium that lines the stomach is damaged by acid and is renewed every two days. Why is mitosis required to repair the damage? A Mitosis repairs damaged cells. B Mitosis produces new genetically similar cells. C Mitosis provides genetically identical replacement cells. D Mitosis doubles the original cell number.

Accepted Answer

C

Question 22

22 What is the role of telomeres? A allowing the chromatids to reach the poles during mitosis B holding sister chromatids together C making sure that the sister chromatids are of identical length D preventing loss of genes during DNA replication

Accepted Answer

D

Question 23

23 Which features of mitosis help to maintain the genetic composition of the cell? 1 the longitudinal division of the centromeres 2 the DNA of the parent cells replicates before mitosis begins 3 the pulling apart of the chromatids to opposite poles A 1, 2 and 3 B 1 and 3 only C 1 only D 2 and 3 only

Accepted Answer

A

Question 24

24 DNA forms a leading strand and a lagging strand during semi-conservative replication. Which row correctly matches the strands to their properties? the strand that is replicated by joining the strand that together short requires DNA ligase sequences of DNA in a 3′ to 5′ direction A lagging lagging B lagging leading C leading leading D leading lagging

Accepted Answer

A

Question 25

25 How many genes could code for one collagen molecule? A 1 gene only B 2 genes only C 3 genes only D 1 gene or 2 genes or 3 genes

Accepted Answer

D

Question 26

26 The diagram shows some events during the formation of an mRNA molecule at transcription. P 5′ 3′ Q Q S R What is correctly identified in the diagram? A P are introns. B Q are exons. C R is a primary transcript. D S are non-coding sequences.

Accepted Answer

D

Question 27

27 Two plants, K and L, are parasites of other plants. Both species grow structures that invade the vascular tissue of plants. Plant K grows into xylem tissue of other plants. Plant L grows into phloem tissue of other plants. Which substances could plants K and L take from the plants that they parasitise? plant K plant L A water only water and sucrose only B water and minerals water, amino acids and sucrose C water only amino acids and sucrose only D water and minerals water and sucrose only

Accepted Answer

B

Question 28

28 Which statements are correct for the apoplast pathway? 1 Water enters the cell wall. 2 Water moves by osmosis. 3 Water moves from cell wall to cell wall. 4 Water moves through plasmodesmata. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Accepted Answer

B

Question 29

29 Mass flow is the bulk movement of materials from one place to another. Which vessels carry fluids by mass flow? 1 artery 2 phloem sieve tube element 3 vein 4 xylem vessel element A 1, 2, 3 and 4 B 1, 2 and 3 only C 1 and 3 only D 2 and 4 only

Accepted Answer

A

Question 30

30 Which features are present in companion cells and also in phloem sieve tube elements?

ribosomes plasmodesmata

v x key

/ = present

0 0O WwW >

v v
x v X = not present
x x

Accepted Answer

B

Question 31

31 Which two terms describe the mammalian circulatory system? A open and double circulation B closed and double circulation C closed and single circulation D open and single circulation

Accepted Answer

B

Question 32

32 One function of an arteriole is to increase or decrease the flow of blood to tissues. Which of these must be present in an arteriole wall to allow this function? 1 collagen 2 endothelium 3 smooth muscle A 1, 2 and 3 B 1 and 3 only C 2 only D 3 only

Accepted Answer

D

Question 33

33 The table shows the blood pressures in different parts of the circulatory system of a person sitting at rest. parts of the blood pressure circulatory system / kPa aorta 16.0 arteriole 11.3 arterial end of capillary 4.7 venous end of capillary 1.3 vein 0.6 What is the percentage decrease in blood pressure between the arteriole and the arterial end of a capillary? A 42% B 58% C 142% D 240%

Accepted Answer

B

Question 34

34 Which reaction is catalysed by carbonic anhydrase? A the dissociation of carbonic acid B the formation of carbaminohaemoglobin C the formation of hydrogencarbonate ions and hydrogen ions D the association of carbon dioxide and water

Accepted Answer

D

Question 35

35 What directly causes the percentage oxygen saturation of haemoglobin to decrease in actively respiring muscles? A hydrogencarbonate ions B carbon dioxide C carbonic acid D hydrogen ions

Accepted Answer

D

Question 36

36 Which row shows the tissues that are present in the wall of the trachea and also the wall of the

bronchus?
ciliated squamous smooth
epithelium | epithelium muscle
A J Jv Jv
B J Jv x
Cc Jv x JV
D x Jv Jv

key
/ = present in trachea and bronchus

X = not present in trachea or bronchus

Accepted Answer

C

Question 37

37 Outbreaks of cholera commonly occur in camps that are set up after a major natural disaster. The list shows some control measures that can be taken to limit the spread of cholera in the camps. 1 treating all drinking water supplies with a high concentration of chlorine 2 setting up an emergency treatment centre to isolate cases of cholera and treat them with antibiotics 3 using concentrated disinfectant to clean sewage disposal areas and infected bedding 4 health workers visiting regularly to detect cases 5 keeping good records of the number of cases and deaths at treatment centres Which features of these control measures involve an economic factor? A 1, 2, 3, 4 and 5 B 1, 3 and 5 only C 2, 3, 4 and 5 only D 2 and 4 only

Accepted Answer

A

Question 38

38 Antibiotics are used to treat many infections. Each antibiotic has one or more biochemical targets.

Tetracycline inhibits 70S ribosomes.

Rifamycin inhibits prokaryotic RNA polymerase.

Which antibiotics can be used to treat an infection caused by the influenza virus?

penicillin tetracycline rifamycin
A v v v
B v x v
Cc x x Jv
D x x x

key
/ =can be used

X = cannot be used

Accepted Answer

D

Question 39

39 Which cells involved in the primary immune response are phagocytes? A monocytes B plasma cells C T-helper cells D T-killer cells

Accepted Answer

A

Question 40

40 Some ways in which different types of monoclonal antibodies can work are described. 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 · Plant cells are stained and then viewed with a simple light microscope, using daylight as…

Q2 · The diagram shows an image of a cell with a scale bar

Q3 · The diagram shows a stage micrometer, with divisions of 0.1 mm, viewed using an eyepiece…

Q4 · What are found in chloroplasts and also in mitochondria?

Q5 · A long-distance runner has become adapted to run faster for longer after regular training

Q6 · Some functions carried out within eukaryotic cells are listed

Q7 · The diagram shows the structure of a unicellular organism

Q8 · Diastase is an enzyme that breaks down starch into maltose

Q9 · Which molecule is required for this reaction to occur?

Q10 · Which molecules contain at least two double bonds?

Q11 · Which description of globular proteins is correct?

Q12 · Which diagram shows where a hydrogen bond occurs between two water molecules?

Q13 · Some detergents disrupt hydrogen bonds between water molecules

Q14 · An investigation was carried out to see if compound X could improve the thermostability…

Q15 · The table shows the results from an investigation into the effect of temperature on an…

Q16 · The graph shows how the rate of a reaction changes with substrate concentration in the…

Q17 · Which of these substances can pass directly through cell surface membranes without using…

Q18 · Which of these statements about facilitated diffusion are correct?

Q19 · A cell absorbs amino acids

Q20 · The diagram shows apparatus set up to investigate the effect of changing the initial…

Q21 · The epithelium that lines the stomach is damaged by acid and is renewed every two days

Q22 · What is the role of telomeres?

Q23 · Which features of mitosis help to maintain the genetic composition of the cell?

Q24 · DNA forms a leading strand and a lagging strand during semi-conservative replication

Q25 · How many genes could code for one collagen molecule?

Q26 · The diagram shows some events during the formation of an mRNA molecule at transcription

Q27 · Two plants, K and L, are parasites of other plants

Q28 · Which statements are correct for the apoplast pathway?

Q29 · Mass flow is the bulk movement of materials from one place to another

Q30 · Which features are present in companion cells and also in phloem sieve tube elements?

Q31 · Which two terms describe the mammalian circulatory system?

Q32 · One function of an arteriole is to increase or decrease the flow of blood to tissues

Q33 · The table shows the blood pressures in different parts of the circulatory system of a…

Q34 · Which reaction is catalysed by carbonic anhydrase?

Q35 · What directly causes the percentage oxygen saturation of haemoglobin to decrease in…

Q36 · Which row shows the tissues that are present in the wall of the trachea and also the wall…

Q37 · Outbreaks of cholera commonly occur in camps that are set up after a major natural…

Q38 · Antibiotics are used to treat many infections

Q39 · Which cells involved in the primary immune response are phagocytes?

Q40 · Some ways in which different types of monoclonal antibodies can work are described

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