Cambridge A Level Biology 9700 — 2021 Oct/Nov Paper 1 · Variant 1

Question 1

1 A student observes a cell using a light microscope. The student then draws the cell. Which items will the student need to calculate the magnification of the drawing? 1 eyepiece graticule 2 ruler 3 hand lens 4 stage micrometer scale A 1, 2, 3 and 4 B 1, 2 and 4 only C 1 and 3 only D 2 and 4 only

Accepted Answer

B

Question 2

2 Which equations correctly show the relationship between magnification, image size and actual size in microscopy? magnification = image size 1 actual size magnification = actual size 2 image size actual size = image size 3 magnification actual size = magnification 4 image size A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Accepted Answer

A

Question 3

3 In which cell structures does DNA transcription occur? chloroplast A D mitochondrion nucleus C B

Accepted Answer

D

Question 4

4 Which rows could correctly identify the nucleic acids present in two different virus particles in a

sample of air?

A

1 and 2

DNA RNA
1 v v key
2 Jv x ¥ = nucleic acid present
3 x Jv X = nucleic acid not present
4 x x
B 1and3 C 2and3 D 3and4

Accepted Answer

C

Question 5

5 Tests on four samples from a mixture of biological molecules gave the results shown in the table. boiled with boiled with excess excess Benedict’s solution after biuret iodine test Benedict’s acid hydrolysis and reagent solution solution neutralisation result blue red purple yellow Which biological molecules were in the mixture? A reducing sugar and protein B reducing sugar, non-reducing sugar and starch C non-reducing sugar and protein D non-reducing sugar and starch only

Accepted Answer

C

Question 6

6 One molecule of X is formed by a single condensation reaction releasing one molecule of water. What is molecule X? A a disaccharide B a phospholipid C a polysaccharide D a triglyceride

Accepted Answer

A

Question 7

7 The table shows some information about carbohydrate polymers.

Which row describes glycogen?

a-1,4

a-1,6

idi lvcosidic shape of function of
gIYCOSICIC glyco molecule molecule
bonds bonds
A v v branched storage key
B v x helical storage v¥ = present
Cc x Jv branched structural X = not present
D x x helical structural

Accepted Answer

A

Question 8

8 The diagrams show four phospholipid molecules. Which molecule could contribute most to the fluidity of a cell surface membrane? A B C D

Accepted Answer

D

Question 9

9 Which properties of phospholipids explain why single layers of phospholipids added to water immediately form bilayers? 1 The hydrophobic fatty acid chains repel water molecules so the tails pack together. 2 The non-polar fatty acid chains are attracted to each other by hydrophobic interactions. 3 Hydrogen bonds form between the phosphate groups and water. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Accepted Answer

A

Question 10

10 The diagrams show three examples of different bonds. bond 2 bond 1 bond 3 O NH O C C N CH2 S S CH2 H Which bonds hold the tertiary structure of proteins together? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Accepted Answer

C

Question 11

11 Which feature of collagen enables it to fulfil a structural role in skin and in tendons? A Adjacent collagen molecules are linked by ester bonds. B Collagen fibres form layers with the fibres in different directions. C Collagen molecules are formed as a triple helix of polypeptide chains. D Polypeptide chains of collagen are tightly folded into compact shapes.

Accepted Answer

C

Question 12

12 The graph shows how the concentrations of four components, 1, 2, 3 and 4, of an enzyme-catalysed reaction change with time. 1 concentration 2 3 4 time Which component is the enzyme–substrate complex? A 1 B 2 C 3 D 4

Accepted Answer

D

Question 13

13 The table shows the Michaelis–Menten constant, Km, for three enzymes. enzyme Km / mmol dm–3 C 1.5  10–2 P 3.0  10–4 F 5.0  10–6 Which interpretation of the information is correct? A Enzyme C has a Vmax which is half that of enzyme P. B Enzyme C will reach Vmax in the shortest time interval. C Enzyme F has the greatest affinity for its substrate. D Enzyme P has a Vmax of 6.0  10–3 mmol dm–3.

Accepted Answer

C

Question 14

14 What explains how a signal molecule produced by one cell can be detected by a target cell? A A signal molecule can bind to any type of cell surface receptor. B A signal molecule has a complementary shape to a cell surface receptor. C Signal molecules enter the cell by diffusion. D Signal molecules enter the cell by endocytosis.

Accepted Answer

B

Question 15

15 Some enzymes are produced in the cells of the pancreas. The enzymes are secreted when required. Which process is used to transport these enzymes out of the cells of the pancreas? A active transport B facilitated diffusion C endocytosis D exocytosis

Accepted Answer

D

Question 16

16 Plant cells were submerged in a solution with a water potential less negative than that found inside the cells. What describes the condition of the plant cells after 20 minutes? A burst B incipient plasmolysis C plasmolysed D turgid

Accepted Answer

D

Question 17

17 What will be present in each chromosome at the end of the G2 phase of the cell cycle? A two centrioles B two centromeres C two molecules of DNA D two telomeres

Accepted Answer

C

Question 18

18 Which events listed are part of the cell cycle? 1 interphase 2 metaphase 3 cytokinesis A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Accepted Answer

A

Question 19

19 Which features of an organism are affected by a drug that kills cells that are dividing mitotically? 1 cell repair 2 cell replacement 3 number of stem cells 4 tissue repair 5 tumour formation A 1, 2, 3, 4 and 5 B 1, 2 and 3 only C 1, 4 and 5 only D 2, 3, 4 and 5 only

Accepted Answer

D

Question 20

20 The graph shows how the distance between sister chromatids (curve P) and the distance between chromatids and centrioles (curve Q) changes during part of mitosis. 40 curve P distance / μm 20 curve Q 0 T V W X time Which statements could be correct? 1 T to V represents interphase. 2 T to W represents metaphase. 3 W to X represents anaphase. A 1 and 3 B 2 and 3 C 1 only D 2 only

Accepted Answer

B

Question 21

21 Which statement helps to explain why the two sugar-phosphate chains in a DNA molecule are a constant distance apart? A Adenine and thymine are held together by the same number of hydrogen bonds as cytosine and guanine. B Each nucleotide molecule is the same size. C Each purine base is linked to a pyrimidine base. D The sugar-phosphate strands of the helix are held together by sulfur bridges.

Accepted Answer

C

Question 22

22 During DNA replication, what must happen before a newly added nucleotide is bonded to the next nucleotide in the strand? 1 complementary base pairing 2 hydrogen bond formation 3 phosphodiester bond formation A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Accepted Answer

B

Question 23

23 An antibiotic enters bacterial cells through a membrane channel protein, P. Some bacterial cells have shown resistance to this antibiotic by acquiring a mutation which alters P. This mutation prevents the entry of the antibiotic into the cell. Which conclusions can be drawn about how resistance to this antibiotic developed in these bacteria? 1 The mutation changed the order of the amino acids in the gene coding for P. 2 The mutation resulted in the production of P with an altered tertiary structure. 3 The antibiotic is a hydrophobic molecule and so cannot cross the phospholipid bilayer to enter the cell. A 1, 2 and 3 B 1 and 3 only C 2 and 3 only D 2 only

Accepted Answer

D

Question 24

24 What is the correct tRNA anticodon coding for the amino acid proline? DNA triplet code amino acid on transcribed strand alanine CGT histidine GTG proline GGT A CCA B CCU C GGT D GGU

Accepted Answer

D

Question 25

25 The table shows the observations made by a student about three different cell types, P, Q and R, seen in a transverse section of a plant stem, using a light microscope. ratio of cell wall width to whole structures observed in cell contents cell width P 1 : 10 none Q 1 : 20 regular pattern of circles in some cells R 1 : 20 granular appearance of all cells What type of cells are P, Q and R? P Q R A companion cell phloem sieve tube element xylem vessel element B companion cell xylem vessel element phloem sieve tube element C xylem vessel element companion cell phloem sieve tube element D xylem vessel element phloem sieve tube element companion cell

Accepted Answer

D

Question 26

26 Water molecules are attracted to each other. This property is important in the upward movement of water in xylem. Which term is used to describe the attraction of water molecules to each other? A adhesion B cohesion C hydrophilic D polar

Accepted Answer

B

Question 27

27 The diagram shows a model to demonstrate mass flow. W water concentrated dilute sucrose solution Y X Z sucrose solution partially permeable partially permeable membrane membrane In a plant, what are the structures W, X, Y and Z and what is the direction of flow of solution along W? phloem xylem roots leaves direction of flow along W A W X Y Z from Z to Y B W X Z Y from Y to Z C X W Y Z from Y to Z D X W Z Y from Z to Y

Accepted Answer

B

Question 28

28 The parts of the heart that control heart action are listed. ● sinoatrial node (SAN) ● atrioventricular node (AVN) ● Purkyne tissue Which row is correct for atrial contraction and ventricular contraction? atrial contraction ventricular contraction A AVN produces SAN produces waves of excitation waves of excitation B Purkyne tissue carries AVN produces waves of excitation waves of excitation C SAN and AVN produce Purkyne tissue carries waves of excitation waves of excitation D SAN produces Purkyne tissue carries waves of excitation waves of excitation

Accepted Answer

D

Question 29

29 The diagram shows part of the circulatory system in a mammal. 1 2 3 4 direction of direction of blood flow vena cava vena cava vena cava blood flow aorta Where is the blood pressure and the speed of flow the lowest? lowest blood lowest speed pressure of flow A 1 4 B 2 3 C 3 2 D 4 1

Accepted Answer

D

Question 30

30 The photomicrograph shows human blood cells. X What type of blood cell is X? A B-lymphocyte B monocyte C phagocyte D T-lymphocyte

Accepted Answer

C

Question 31

31 The diagram shows some of the reactions of carbon dioxide when it enters the blood from cells in a metabolically active tissue. Which reaction is catalysed by the enzyme carbonic anhydrase? CO2 plasma A B CO2  +  H2O       H2CO3       H+  +  HCO3 − C D CO2  +  H2O       H2CO3       H+  +  HCO3 − red blood cell

Accepted Answer

C

Question 32

32 The graph shows the oxygen dissociation curves for haemoglobin in animals that live at high altitude and animals that live at low altitude. 100 high altitude percentage saturation of haemoglobin low with oxygen altitude 0 partial pressure of oxygen / kPa What explains the oxygen dissociation curve at high altitude? A Haemoglobin has a higher affinity for oxygen. B Haemoglobin releases oxygen more readily. C The change in partial pressure of carbon dioxide causes a Bohr effect. D The decrease in percentage of carbon dioxide causes the curve to shift to the left.

Accepted Answer

A

Question 33

33 The diagram shows three features found in the mammalian gas exchange system. ciliated goblet epithelium cells X cartilage Which structures of the gas exchange system could be represented by X in the diagram? A small bronchiole only B small bronchiole and bronchus C trachea only D trachea and bronchus

Accepted Answer

D

Question 34

34 What are short-term effects of nicotine on the cardiovascular system? 1 constriction of small arteries 2 increase in heart rate 3 increase in blood pressure A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Accepted Answer

A

Question 35

35 Some features of a disease are listed. ● It can be transmitted by animals to other animals, including humans. ● One mode of transmission is by transfusion with contaminated blood. ● The causative organism can show multiple drug resistance. ● The majority of humans who die from the disease are children. Which disease has all these features? A cholera B HIV / AIDS C malaria D tuberculosis

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 Which description of multiple drug resistance in bacteria is correct? A Bacteria have DNA with resistant genes for several different types of antibiotic. B Different species of bacteria have DNA with resistant genes for one type of antibiotic. C Large numbers of one species of bacteria are immune to several different types of antibiotic. D Many different species of bacteria are immune to one type of antibiotic.

Accepted Answer

A

Question 38

38 Which description of a T-lymphocyte is correct? A They are only found in blood and secrete cytokines in response to infection. B They can leave the blood and accumulate at sites of inflammation. C They can leave the blood and secrete cytotoxins when exposed to bacteria. D They circulate in the blood and always present antigens in response to infection.

Accepted Answer

B

Question 39

39 Where are antibodies found during an immune response?

on the surface in blood
of memory cells plasma
A J J
B Jv x
Cc x v
D x x

key
JY = antibodies found

X = antibodies not found

Accepted Answer

A

Question 40

40 Monoclonal antibodies are used in the diagnosis and treatment of disease. They are produced using a technique known as cell fusion. Which two structures are fused together in this technique? A antigens and hybridoma cells B T-lymphocytes and cancer cells C cancer cells and plasma cells D hybridoma cells and antibodies

Accepted Answer

C

Question paper16 pages

Mark scheme3 pages

Questions as text

Q1 · A student observes a cell using a light microscope

Q2 · Which equations correctly show the relationship between magnification, image size and…

Q3 · In which cell structures does DNA transcription occur?

Q4 · Which rows could correctly identify the nucleic acids present in two different virus…

Q5 · Tests on four samples from a mixture of biological molecules gave the results shown in…

Q6 · One molecule of X is formed by a single condensation reaction releasing one molecule of…

Q7 · The table shows some information about carbohydrate polymers

Q8 · The diagrams show four phospholipid molecules

Q9 · Which properties of phospholipids explain why single layers of phospholipids added to…

Q10 · The diagrams show three examples of different bonds

Q11 · Which feature of collagen enables it to fulfil a structural role in skin and in tendons?

Q12 · The graph shows how the concentrations of four components, 1, 2, 3 and 4, of an…

Q13 · The table shows the Michaelis–Menten constant, Km, for three enzymes

Q14 · What explains how a signal molecule produced by one cell can be detected by a target cell?

Q15 · Some enzymes are produced in the cells of the pancreas

Q16 · Plant cells were submerged in a solution with a water potential less negative than that…

Q17 · What will be present in each chromosome at the end of the G2 phase of the cell cycle?

Q18 · Which events listed are part of the cell cycle?

Q19 · Which features of an organism are affected by a drug that kills cells that are dividing…

Q20 · The graph shows how the distance between sister chromatids (curve P) and the distance…

Q21 · Which statement helps to explain why the two sugar-phosphate chains in a DNA molecule are…

Q22 · During DNA replication, what must happen before a newly added nucleotide is bonded to the…

Q23 · An antibiotic enters bacterial cells through a membrane channel protein, P

Q24 · What is the correct tRNA anticodon coding for the amino acid proline?

Q25 · The table shows the observations made by a student about three different cell types, P, Q…

Q26 · Water molecules are attracted to each other

Q27 · The diagram shows a model to demonstrate mass flow

Q28 · The parts of the heart that control heart action are listed

Q29 · The diagram shows part of the circulatory system in a mammal

Q30 · The photomicrograph shows human blood cells

Q31 · The diagram shows some of the reactions of carbon dioxide when it enters the blood from…

Q32 · The graph shows the oxygen dissociation curves for haemoglobin in animals that live at…

Q33 · The diagram shows three features found in the mammalian gas exchange system

Q34 · What are short-term effects of nicotine on the cardiovascular system?

Q35 · Some features of a disease are listed

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

Q37 · Which description of multiple drug resistance in bacteria is correct?

Q38 · Which description of a T-lymphocyte is correct?

Q39 · Where are antibodies found during an immune response?

Q40 · Monoclonal antibodies are used in the diagnosis and treatment of disease

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