Cambridge A Level Biology 9700 — 2025 Oct/Nov Paper 1 · Variant 1

Question 1

1 In a photomicrograph of magnification 5000, a chloroplast measures 25 mm in diameter. What is the actual diameter of the chloroplast? A 0.2 m B 0.5 m C 2 m D 5 m

Accepted Answer

D

Question 2

2 What is a function of Golgi bodies? A formation of vesicles for endocytosis B modification of proteins for secretion C synthesis of ATP D synthesis of polypeptides

Accepted Answer

B

Question 3

3. Acell in the human body is specialised for synthesis and secretion of lipids.

Which row shows the organelles required by the cell for synthesis and secretion of lipids?

smooth
mitochondria | endoplasmic vesicles
reticulum
key
v = required

X = not required

Accepted Answer

A

Question 4

4 The photomicrograph shows part of a cell.

Which row is correct?

the organelles

this cell will this could be | shown could be
contain 70S part of a used to make
ribosomes plant cell antibodies
key
¥ = correct

X = not correct

Accepted Answer

A

Question 5

5 Which statement about viruses is correct? A They are cells with a capsid made of phospholipids. B They are cells with a capsid made of protein. C They are particles with a capsid made of phospholipids. D They are particles with a capsid made of protein.

Accepted Answer

D

Question 6

6 Solution X was tested for the presence of non-reducing sugars. It did not contain reducing sugars. Some steps that can be used to test for the presence of biological molecules are listed. 1 Add Benedict’s solution to the test-tube. 2 Add dilute hydrochloric acid to the test-tube. 3 Add sodium hydrogencarbonate to the test-tube. 4 Heat the test-tube in a water-bath. Which order of steps to identify the presence of non-reducing sugars in solution X is correct? A 1  4 B 2  3  1  4 C 2  4  3  1  4 D 3  2  4  1

Accepted Answer

C

Question 7

7 The diagram shows the structure of part of a biological molecule. HOH2C O O CH2 O HO CH2OH OH OH OH OH HOH2C O O HO CH2 OH HOH2C O O CH2 O O CH2 O O HO HO HO CH2OH CH2OH CH2 OH OH OH HOH2C O O HO CH2 OH HOH2C O O HO CH2 OH Which statements about this biological molecule are correct? 1 It has monomers joined by ester bonds. 2 It is a macromolecule. 3 It is a polysaccharide. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Accepted Answer

D

Question 8

8 Which diagram has a covalent bond that joins monomers together to form a biological polymer in eukaryotes? A B C D O R H O R O R R NH3 + –O C R C O R O R O P O R O–

Accepted Answer

D

Question 9

9 Which feature of storage polysaccharides means they do not change the water potential of cells? A They are easily hydrolysed. B They are compact. C They are insoluble. D They are branched molecules.

Accepted Answer

C

Question 10

10 Which molecules contain at least four double bonds? saturated triglyceride C A D collagen haemoglobin B

Accepted Answer

B

Question 11

11 In some people a mutation can affect the beta chains in their haemoglobin molecules. As a result polar amino acids on the outer surfaces of the chains are replaced by non-polar amino acids. What will be the effect on haemoglobin? A Haemoglobin will become less soluble. B Haemoglobin will become more soluble. C Hydrophobic interactions between amino acids will decrease. D More hydrogen bonds will form in the molecule.

Accepted Answer

A

Question 12

12 The graph shows the effect of substrate concentration on an enzyme-catalysed reaction with and without a competitive inhibitor. rate of key reaction with inhibitor without inhibitor substrate concentration What is the effect of the competitive inhibitor on Vmax and Km? A Vmax decreases and Km decreases. B Vmax stays the same and Km decreases. C Vmax stays the same and Km increases. D Vmax decreases and Km stays the same.

Accepted Answer

C

Question 13

13 The graph shows energy changes in a chemical reaction. 1 2 4 energy 3 progress of reaction What is the activation energy when an enzyme is added? A 1 + 2 B 2 only C 3 – 2 D 4

Accepted Answer

B

Question 14

14 The diagram shows an enzyme, its substrate and an enzyme–substrate complex. enzyme substrate enzyme–substrate complex Which statement explains how this substrate is able to enter the active site of this enzyme? A Contact between the substrate and the enzyme causes a change in the enzyme shape. B The shape of the active site and the shape of the substrate are complementary. C The substrate within the active site forms hydrogen bonds with amino acids. D When the enzyme–substrate complex forms, the tertiary structure of the enzyme changes.

Accepted Answer

A

Question 15

15 What are the main roles of glycolipids in cell surface membranes? 1 to help cells to attach to each other to form tissues 2 to act as antigens for cell-to-cell recognition 3 to increase fluidity for the cell surface membrane A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Accepted Answer

B

Question 16

16 A sample of healthy plant cells taken from the same tissue is placed in a beaker containing distilled water. The cells change in size. What would explain this change in size? A Water will leave the cells by active transport. B Water will enter the cells by osmosis. C Solutes will enter the cells by active transport. D Solutes will leave the cells by osmosis.

Accepted Answer

B

Question 17

17 A student studying surface area to volume ratio and diffusion made a cuboid, S1, using agar stained blue with a pH indicator. The dimensions of S1 are shown in the diagram. The student made a second agar cuboid, S2. Each dimension of S2, (the length, the width and the height), was half that of S1. S1 S2 30 mm not to scale 15 mm 5 mm 2.5 mm 8 mm 4 mm The student placed each cuboid in a test-tube and covered it in acid. The time taken for each cuboid to completely change colour was recorded. All variables other than the size of the cuboids were standardised. Which row shows the surface area to volume ratio of S1 and the time taken for S1 to change colour completely in acid compared to the time taken for S2 to change colour completely? time taken for S1 to change surface area to colour completely in acid volume ratio of S1 compared to S2 A 0.72 : 1 S1 takes less time than S2 B 0.72 : 1 S1 takes more time than S2 C 1.4 : 1 S1 takes less time than S2 D 1.4 : 1 S1 takes more time than S2

Accepted Answer

B

Question 18

18 Two test-tubes, labelled X and Y, were set up containing equal volumes of solution X or solution Y respectively. A large number of type P cells and a large number of type Q cells were added into test-tube X and also into test-tube Y. After a few minutes, samples of the solutions were taken and the cells were observed with a microscope. ● In solution X, all of cell type P had burst and cell type Q had not burst. ● In solution Y, no cells had burst. Which row correctly identifies cell type Q and solutions X and Y? cell type Q solution X solution Y A red blood cells 5% NaCl solution distilled water B goblet cells 5% glucose solution distilled water C liver cells distilled water 5% glucose solution D root hair cells distilled water 5% NaCl solution

Accepted Answer

D

Question 19

19 A human muscle cell contains 46 chromosomes. How many centromeres will be present in a cell during the stages of the mitotic cell cycle? early prophase metaphase anaphase A 46 46 92 B 46 92 92 C 46 46 46 D 92 46 46

Accepted Answer

A

Question 20

20 Telomeres become shorter during each cell cycle of a specialised cell. In which phase of the cell cycle do telomeres shorten? A cytokinesis B G1 C S D G2

Accepted Answer

C

Question 21

21 The photomicrographs show stages of mitosis. 1 2 3 4 5 What is the correct order for the stages of mitosis? A 2  3  5  1  4 B 2  4  1  5  3 C 3  2  5  4  1 D 5  1  4  3  2

Accepted Answer

A

Question 22

22 The gene that codes for protein R is 130 kb long. Protein R is 220 kDa in mass. The typical mass of an amino acid is 110 Da. (1000 base pairs = 1 kb, 1000 Da = 1 kDa) Which row is correct? approximate length approximate length of introns in this of mRNA for this gene / base pairs gene / base pairs A 6000 6000 B 6000 130 000 C 124 000 6000 D 124 000 130 000

Accepted Answer

C

Question 23

23 The diagram shows a section of DNA. Two of the bases in this section are labelled 1 and 2. O 1 O O O O O 2 Which row correctly identifies the bases 1 and 2? base 1 base 2 A purine adenine B purine guanine C pyrimidine adenine D pyrimidine guanine

Accepted Answer

B

Question 24

24 Which row describes the role of the enzymes DNA polymerase and DNA ligase? DNA polymerase DNA ligase A adds nucleotides in joins sections of DNA together a 5′ to 3′ direction on the lagging strand B adds nucleotides in joins sections of DNA together a 3′ to 5′ direction on the leading strand C adds nucleotides in joins sections of DNA together a 3′ to 5′ direction on the lagging strand D adds nucleotides in joins sections of DNA together a 5′ to 3′ direction on the leading strand

Accepted Answer

A

Question 25

25 The table shows some of the DNA triplet codes for some amino acids. amino acid DNA triplet code amino acid DNA triplet code arginine GCA glycine CCA arginine GCC glycine CCG arginine GCG glycine CCT asparagine TTA lysine TTC asparagine TTG lysine TTT cysteine ACA proline GGA cysteine ACG proline GGC STOP ATC valine CAC The base sequence on the template DNA strand coding for part of a polypeptide is shown. CCA TTC ACG GCG TTA GCA Two mutations occur in this sequence during DNA replication. Which mutated DNA would result in two different amino acids? A CCA ATC ACG GCG TTG GCA B CCA TTC ACA GCA TTA GCA C CCA TTC ACG CCG TTA GCC D CCA TTC ACG GCG TTC GGA

Accepted Answer

D

Question 26

26 The diagram shows a vertical section through part of the stem of a dicotyledonous plant. Three types of structures are labelled. U V W What are the structures U, V and W? companion phloem sieve xylem vessel cells tube elements elements A U W V B V U W C U V W D W V U

Accepted Answer

B

Question 27

27 Which features of xylem vessels help to reduce the resistance to water flow? 1 Lignin forms an incomplete secondary wall. 2 There are no cross walls between the vessel elements. 3 The xylem vessels form narrow tubes. A 1, 2 and 3 B 1 and 2 only C 2 only D 3 only

Accepted Answer

C

Question 28

28 What causes water to move from the root hair cells to the endodermis? A diffusion through cell walls and osmosis down a water potential gradient in the cytoplasm B diffusion through the symplast and osmosis and root pressure through the apoplast C osmosis from cell vacuole to cell vacuole and active transport into the endodermis D osmosis through the intercellular spaces and diffusion in cell walls and cytoplasm

Accepted Answer

A

Question 29

29 Which changes occur as carbohydrate is moved into a sink? water potential volume of liquid of the sieve tube of the sieve element becomes tube element A lower decreases B lower increases C higher decreases D higher increases

Accepted Answer

C

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 contain lymphocytes. D Tissue fluid is formed from blood plasma and is not returned to blood plasma.

Accepted Answer

A

Question 31

31 The body maintains an average normal blood pH of 7.4. Which row describes the conditions that would increase the dissociation rate of haemoglobin the most during periods of intense exercise? blood CO2 partial blood pH pressure / kPa A 7.2 5.6 B 7.2 9.5 C 7.6 5.6 D 7.6 9.5

Accepted Answer

B

Question 32

32 The graph shows changes in blood pressure during one cardiac cycle. 16 14 12 10 blood key pressure 8 aorta / kPa ventricle 6 atrium 4 2 0 0 X 0.75 time / s What is happening at time X? aortic semilunar atrium valve A closing emptying B closing filling C opening emptying D opening filling

Accepted Answer

D

Question 33

33 How many times must a carbon dioxide molecule pass through a cell surface membrane to travel from the tissue fluid into the blood plasma? (Assume there are no pores between the cells the carbon dioxide molecule must pass through.) A 1 B 2 C 3 D 4

Accepted Answer

B

Question 34

34 Two types of epithelial cells, 1 and 2, occur in the mammalian gas exchange system in a healthy human. 1 2 Which row shows the function and distribution of these types of epithelial cells? cell type 1 cell type 2 A absorption in bronchi secrete mucus in alveoli B exchange surface in alveoli secrete mucus in bronchi C absorption in bronchi move mucus in alveoli D exchange surface in alveoli move mucus in bronchi

Accepted Answer

D

Question 35

35 Which tissues would be seen in a photomicrograph of the wall of the trachea?

a elastic fibres smooth muscle

x v key

v x
v v
x x

/ = present

X = not present

0 ONO WwW >

Accepted Answer

C

Question 36

36 The graph shows the decrease in cases of tuberculosis (TB) in a country between 1910 and 2000. 90 000 80 000 70 000 60 000 number 50 000 of cases per year 40 000 30 000 20 000 10 000 0 1910 1920 1940 1960 1980 2000 year Which factors could have contributed to the fall over this period? 1 pasteurisation of milk 2 the provision of new housing to reduce overcrowding 3 removing large pools of stagnant water 4 identification of contacts of people infected with TB A 1, 2 and 4 B 1 and 3 C 1 and 4 only D 2, 3 and 4

Accepted Answer

A

Question 37

37 The pathogens for some diseases are transmitted by vectors. Which disease is transmitted with the help of a vector that could be controlled by the removal of pools of water? A cholera B HIV/AIDS C malaria D tuberculosis

Accepted Answer

C

Question 38

38 How does penicillin affect bacteria? A It inhibits DNA replication by binding to nucleotides. B It inhibits translation by preventing tRNA binding to ribosomes. C It is a competitive inhibitor of an enzyme in cell wall synthesis. D It is a competitive inhibitor of an enzyme in protein synthesis.

Accepted Answer

C

Question 39

39 The hybridoma method is used for the production of monoclonal antibodies. Which two types of cell are used in this method? A stem cell and B-lymphocyte B stem cell and T-lymphocyte C tumour cell and B-lymphocyte D tumour cell and T-lymphocyte

Accepted Answer

C

Question 40

40 What describes a non-specific immune response? A activation of killer T-lymphocytes by infected cells B cloning of B-lymphocytes to form plasma cells C ingestion of a bacterial cell by a neutrophil D recognition of antigens on the cell surface of macrophages

Accepted Answer

C

Question paper20 pages

Mark scheme3 pages

Questions as text

Q1 · In a photomicrograph of magnification 5000, a chloroplast measures 25 mm in diameter

Q2 · What is a function of Golgi bodies?

Q3 · Acell in the human body is specialised for synthesis and secretion of lipids

Q4 · The photomicrograph shows part of a cell

Q5 · Which statement about viruses is correct?

Q6 · Solution X was tested for the presence of non-reducing sugars

Q7 · The diagram shows the structure of part of a biological molecule

Q8 · Which diagram has a covalent bond that joins monomers together to form a biological…

Q9 · Which feature of storage polysaccharides means they do not change the water potential of…

Q10 · Which molecules contain at least four double bonds?

Q11 · In some people a mutation can affect the beta chains in their haemoglobin molecules

Q12 · The graph shows the effect of substrate concentration on an enzyme-catalysed reaction…

Q13 · The graph shows energy changes in a chemical reaction

Q14 · The diagram shows an enzyme, its substrate and an enzyme–substrate complex

Q15 · What are the main roles of glycolipids in cell surface membranes?

Q16 · A sample of healthy plant cells taken from the same tissue is placed in a beaker…

Q17 · A student studying surface area to volume ratio and diffusion made a cuboid, S1, using…

Q18 · Two test-tubes, labelled X and Y, were set up containing equal volumes of solution X or…

Q19 · A human muscle cell contains 46 chromosomes

Q20 · Telomeres become shorter during each cell cycle of a specialised cell

Q21 · The photomicrographs show stages of mitosis

Q22 · The gene that codes for protein R is 130 kb long

Q23 · The diagram shows a section of DNA

Q24 · Which row describes the role of the enzymes DNA polymerase and DNA ligase?

Q25 · The table shows some of the DNA triplet codes for some amino acids

Q26 · The diagram shows a vertical section through part of the stem of a dicotyledonous plant

Q27 · Which features of xylem vessels help to reduce the resistance to water flow?

Q28 · What causes water to move from the root hair cells to the endodermis?

Q29 · Which changes occur as carbohydrate is moved into a sink?

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

Q31 · The body maintains an average normal blood pH of 7.4

Q32 · The graph shows changes in blood pressure during one cardiac cycle

Q33 · How many times must a carbon dioxide molecule pass through a cell surface membrane to…

Q34 · Two types of epithelial cells, 1 and 2, occur in the mammalian gas exchange system in a…

Q35 · Which tissues would be seen in a photomicrograph of the wall of the trachea?

Q36 · The graph shows the decrease in cases of tuberculosis (TB) in a country between 1910 and…

Q37 · The pathogens for some diseases are transmitted by vectors

Q38 · How does penicillin affect bacteria?

Q39 · The hybridoma method is used for the production of monoclonal antibodies

Q40 · What describes a non-specific immune response?

What was in this paper

What you needed in this session

Other variants, same session

This paper, other years