Cambridge A Level Biology 9700 — 2019 May/June Paper 1 · Variant 3

Question 1

1 Which combination of lenses for a light microscope will give the greatest magnification? eyepiece lens objective lens A ×5 ×100 B ×10 ×40 C ×15 ×40 D ×15 ×100

Accepted Answer

D

Question 2

2 The photomicrograph shows some mesophyll tissue from a dicotyledonous leaf. 5 µm What is the magnification of the photomicrograph? A × 280 B × 2800 C × 3570 D × 7000

Accepted Answer

B

Question 3

3 The diagram shows a typical animal cell as seen using an electron microscope. 1 5 2 4 3 Which of the numbered structures are needed for proteins to be secreted at the cell surface membrane? A 2, 3, 4 and 5 B 1, 2 and 4 C 1 and 3 D 5 only

Accepted Answer

C

Question 4

4 Lysosomes vary in shape and size, making them difficult to identify. What describes a lysosome? A a vesicle containing enzymes, enclosed by a double membrane, that is budded off the endoplasmic reticulum B a vesicle containing hydrolytic enzymes and surrounded by a single membrane, found only in phagocytes C a vesicle enclosed by a single membrane, containing several different hydrolytic enzymes that may act inside or outside the cell D a vesicle surrounded by a double membrane, containing enzymes which can hydrolyse damaged organelles in a cell

Accepted Answer

C

Question 5

5 Which statements about ATP are correct? 1 It is produced in mitochondria only. 2 It can be hydrolysed to form ADP. 3 It contains deoxyribose. A 1 and 3 B 1 only C 2 and 3 D 2 only

Accepted Answer

D

Question 6

6 A single-celled organism lives inside the body of a fish. This single-celled organism is rod-shaped, 700 µm long, enclosed in a cell wall and has cytoplasm containing thousands of copies of small, circular DNA. Which statement about this single-celled organism is correct? A It is a eukaryote, because it can be seen without using a microscope. B It is a eukaryote, because it is too large to be a prokaryote. C It is a plant, because it is enclosed in a cell wall. D It is a prokaryote, because it has small, circular DNA in its cytoplasm.

Accepted Answer

D

Question 7

7 A solution of amylase was added to a suspension of starch. The mixture was stirred and kept at 40 °C for 45 minutes. Samples were then tested with various reagents. What is the expected set of results? test and resulting colour iodine test Benedict’s test biuret test A black blue blue B black orange purple C brown blue blue D brown orange purple

Accepted Answer

D

Question 8

8 The diagram shows three hexose sugars. CH2OH CH2OH CH2OH O C O C O H H H OH OH H H C C C C C C OH H OH H H OH HO OH HO H H CH2OH C C C C C C H OH H OH OH H 1 2 3 Which row correctly shows examples of carbohydrates in which these three hexose sugars occur? sucrose cellulose amylose A 1 2 3 B 1 3 2 C 2 3 1 D 3 2 1

Accepted Answer

D

Question 9

9 What can occur as a result of a condensation reaction? 1 A disaccharide is formed. 2 A glycosidic bond is broken. 3 A molecule of water is produced. 4 Two monosaccharides join together. A 1, 2 and 3 B 1, 2 and 4 C 1, 3 and 4 D 2, 3 and 4

Accepted Answer

C

Question 10

10 The diagram shows some relationships between features of carbohydrates. α-glucose 1,4 bonds 1 4 3 2 branched Which row correctly matches the carbohydrate with some of its features? 1 2 3 4 A amylopectin sucrose glycogen cellulose B amylose glycogen amylopectin cellulose C cellulose amylopectin glycogen sucrose D glycogen cellulose amylose amylopectin

Accepted Answer

B

Question 11

11 Which row describes a triglyceride?

v Jv key

v Xx ¥ = correct

x v X = not correct
x x

Accepted Answer

D

Question 12

12 The diagram shows three triglycerides, X, Y and Z. O H2COC O X HCOC O H2COC O H2COC O Y HCOC O H2COC O H2COC O Z HCOC O H2COC What is correct for these triglycerides? contains contains contains more saturated unsaturated than two different fatty acids fatty acids fatty acids A X, Y and Z X and Y X and Y B X, Y and Z Z X and Y C X and Y X, Y and Z X, Y and Z D Z X and Y X, Y and Z

Accepted Answer

A

Question 13

13 Which features of collagen result in it having high tensile strength? 1 Bonds form between adjacent molecules. 2 Each three-stranded molecule is held together by hydrogen bonds. 3 Every third amino acid in the polypeptide is small. 4 The primary structure is held together by peptide bonds. A 1, 2 and 3 B 1, 3 and 4 C 1 and 2 only D 2, 3 and 4

Accepted Answer

A

Question 14

14 Which levels of protein structure would always be changed if an enzyme works by the induced fit
hypothesis?

primary secondary tertiary quaternary

v v v v key

¥ = always changed

0 0O WwW D>

v v x
x Jv x X = not changed
x x x

< « x

Accepted Answer

D

Question 15

15 The enzyme β-galactosidase can catalyse the hydrolysis of four substrates, A, B, C and D, with similar structures. Each substrate has a different Km value. For which substrate does β-galactosidase have the lowest affinity? A Km = 4 × 10–3 mol dm–3 B Km = 1 × 10–3 mol dm–3 C Km = 2 × 10–4 mol dm–3 D Km = 1 × 10–4 mol dm–3

Accepted Answer

A

Question 16

16 Which is correct for competitive inhibitors of enzymes? 1 They occupy the active site of an enzyme. 2 They have exactly the same shape as the substrate. 3 They can be used to control the rate of enzyme activity. 4 They can bind to a site on an enzyme other than the active site. A 1, 2 and 3 B 1 and 3 only C 1 only D 2, 3 and 4

Accepted Answer

B

Question 17

17 The diagram represents the fluid mosaic model of membrane structure. 3 2 1 4 6 5 Which two of the numbered components contribute to the fluidity of the membrane? A 1 and 3 B 2 and 4 C 3 and 5 D 4 and 6

Accepted Answer

D

Question 18

18 The cell surface membranes of some cells are largely made up of phospholipids and cholesterol, with few proteins. Which transport mechanisms will be reduced across these membranes? 1 facilitated diffusion 2 active transport 3 diffusion A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Accepted Answer

B

Question 19

19 One of the glycoproteins present in the cell surface membrane of human cells is called ICAM-1. ICAM-1 is a cell adhesion molecule and it is also used by the common cold virus to attach to human cells. Which statements are true about ICAM-1? 1 A drug binding to ICAM-1 to block the common cold virus could stop cells attaching to each other. 2 Part of the ICAM-1 structure must be complementary to proteins in the coat of the common cold virus. 3 The ICAM-1 structure must have hydrophobic parts to stabilise it within the cell membrane. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Accepted Answer

A

Question 20

20 A student weighed a cylinder of potato and then put it into a test-tube containing a salt solution. The potato cylinder was removed from the salt solution after one hour. It was blotted dry and then reweighed. The student recorded that the potato had lost mass. Which row shows the correct explanation for the results the student collected? water potential condition of the of the potato cells potato cells before soaking after soaking A higher plasmolysed B higher turgid C lower plasmolysed D lower turgid

Accepted Answer

A

Question 21

21 Some parts of a typical human chromosome are more numerous than others. Which of the parts are listed in order from the most numerous to the least numerous? A centromere, nucleotide, histone B DNA molecule, telomere, centromere C histone, telomere, DNA molecule D telomere, centromere, nucleotide

Accepted Answer

C

Question 22

22 The enzyme telomerase prevents loss of telomeres after many mitotic cell cycles. Which cells need to transcribe telomerase enzyme? 1 stem cells 2 activated memory B-lymphocytes 3 helper T-lymphocytes secreting cytokines 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 The diagram shows a cell during mitosis. Which description correctly identifies the cell? A a plant cell during anaphase B a plant cell during metaphase C an animal cell during anaphase D an animal cell during metaphase

Accepted Answer

C

Question 24

24 A gene codes for the production of a protein, p53, that binds to damaged DNA during interphase and prevents its replication. A carcinogen in cigarette smoke mutates this gene. Which statement explains why this mutation may cause cancer? A Cells with no p53 are allowed to undergo mitosis. B Cells with no p53 allow their damaged DNA to replicate. C The carcinogen in cigarette smoke increases the rate of cell division. D The p53 causes uncontrolled cell division.

Accepted Answer

B

Question 25

25 What is the role of DNA polymerase? A condensation reactions to produce DNA nucleotides for replication B correct alignment of RNA nucleotides along a template strand of DNA C formation of bonds to complete the sugar-phosphate backbone D formation of glycosidic bonds between complementary base pairs

Accepted Answer

C

Question 26

26 Which row represents the correct features of the nitrogenous base thymine?

has a

forms two hydrogen

single ring is a purine bonds with its pars with
cytosine
structure complementary base
A v v x x key
B Jv x J x / = correct
Cc x v x v X = not correct
D x x v v

Accepted Answer

B

Question 27

27 Meselson 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 second generation and their DNA 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 second generation produced in the medium containing light nitrogen? percentage of heavy percentage of hybrid DNA strands DNA molecules A 25 25 B 25 50 C 50 25 D 50 50

Accepted Answer

B

Question 28

28 The table shows 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 STOP ATC proline GGA cysteine ACA proline GGC cysteine ACG valine CAC The base sequence on the DNA strand coding for a polypeptide is shown. CCA TTC ACG GCG TTA GCA Two mutations occur in this sequence during DNA replication. Which mutated DNA would have no effect on the polypeptide synthesised? A CCA ATC ACG GCG TTG GCA B CCA TTC ACA GCA TTA GCA C CCA TTC ACG CCG TTA GCC D CCT TTC ACG GCG TTA GGA

Accepted Answer

B

Question 29

29 A group of students were asked to look at the photomicrograph of a cross-section of unfamiliar material and make observations. X The students described X as: 1 circular 2 a hollow tube 3 a spherical structure. Which descriptions are correct? A 1, 2 and 3 B 1 and 2 only C 1 only D 3 only

Accepted Answer

C

Question 30

30 Irrigating crop plants with water containing low concentrations of salt causes an increase in the concentration of salt in the soil. What explains why the increase in salt concentration eventually kills the crop? water potential water potential direction of water in roots in soil movement A ↓ into the roots key B ↑ into the soil solution ↑ = water potential increases C ↓ out of the roots ↓ = water potential decreases D ↑ into the roots

Accepted Answer

C

Question 31

31 The photomicrograph shows a transverse section through part of a plant root. Which tissue inhibits the path of water through the apoplastic pathway? D A B C

Accepted Answer

B

Question 32

32 The table shows some information about three blood vessels, P, Q and R, from a mammal. wall percentage composition of wall diameter thickness / mm muscle collagen elastin / mm P 25 2 22 33 40 Q 20 1 25 40 25 R 4 1 35 25 30 Which row identifies blood vessels P, Q and R? P Q R A artery vein artery B artery vein capillary C vein artery capillary D vein artery vein

Accepted Answer

A

Question 33

33 Which row correctly identifies the locations in which a type of molecule or cell is present?

type of molecule or cell blood lymph tsue
antigen v v v
glucose v x v
lymphocyte x v Xx
neutrophil x v Jv

key
v¥ = is present

X = is not present

Accepted Answer

A

Question 34

34 The graph shows the percentage saturation of haemoglobin with oxygen at different partial pressures of oxygen. Which range of partial pressures of oxygen results in the greatest change of percentage saturation of haemoglobin per kPa? 100 D C 80 60 percentage B saturation of haemoglobin with oxygen 40 A 20 0 0 5 10 15 20 partial pressure of oxygen / kPa

Accepted Answer

B

Question 35

35 How many layers of cell surface membrane separate an oxygen molecule in the air space of an alveolus from the nearest haemoglobin molecule? A 3 B 4 C 5 D 6

Accepted Answer

C

Question 36

36 Which biochemical is formed and what happens to the oxygen dissociation curve of adult haemoglobin when carbon dioxide combines with haemoglobin? biochemical formed oxygen dissociation curve A carbaminohaemoglobin shifts to the left B carbaminohaemoglobin shifts to the right C carboxyhaemoglobin shifts to the left D carboxyhaemoglobin shifts to the right

Accepted Answer

B

Question 37

37 The diagram has been used to identify four infectious diseases. infectious disease waterborne not waterborne 1 virus not a virus 4 airborne not airborne 2 3 Which row correctly identifies the infectious diseases? 1 2 3 4 A cholera measles HIV / AIDS TB B cholera smallpox malaria measles C malaria HIV / AIDS TB cholera D malaria TB measles cholera

Accepted Answer

A

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 Growth factors are chemicals that stimulate a cell to divide. Growth factors are transported around the body in the blood, and they attach to cells that have complementary growth factor receptors on their surface. Some cells have too many growth factor receptors on their surface and so the cells continue to divide, forming a tumour. Trastuzumab is used as a treatment for some cancers. Trastuzumab works by binding to a specific growth factor receptor on a tumour cell. This stops the cell dividing and the cell dies. What is trastuzumab? A a monoclonal antibody B a vaccine C an antibiotic D an enzyme inhibitor

Accepted Answer

A

Question 40

40 What describes artificial active immunity? A protection against a pathogen by an injection of antibodies B protection against a pathogen by drinking colostrum containing antibodies C stimulation of lymphocytes by antigens contained in a vaccine D stimulation of lymphocytes by antigens on the surface of invading pathogens

Accepted Answer

C

Question paper20 pages

Mark scheme3 pages

Questions as text

Q1 · Which combination of lenses for a light microscope will give the greatest magnification?

Q2 · The photomicrograph shows some mesophyll tissue from a dicotyledonous leaf

Q3 · The diagram shows a typical animal cell as seen using an electron microscope

Q4 · Lysosomes vary in shape and size, making them difficult to identify

Q5 · Which statements about ATP are correct?

Q6 · A single-celled organism lives inside the body of a fish

Q7 · A solution of amylase was added to a suspension of starch

Q8 · The diagram shows three hexose sugars

Q9 · What can occur as a result of a condensation reaction?

Q10 · The diagram shows some relationships between features of carbohydrates

Q11 · Which row describes a triglyceride?

Q12 · The diagram shows three triglycerides, X, Y and Z

Q13 · Which features of collagen result in it having high tensile strength?

Q14 · Which levels of protein structure would always be changed if an enzyme works by the…

Q15 · The enzyme β-galactosidase can catalyse the hydrolysis of four substrates, A, B, C and D…

Q16 · Which is correct for competitive inhibitors of enzymes?

Q17 · The diagram represents the fluid mosaic model of membrane structure

Q18 · The cell surface membranes of some cells are largely made up of phospholipids and…

Q19 · One of the glycoproteins present in the cell surface membrane of human cells is called…

Q20 · A student weighed a cylinder of potato and then put it into a test-tube containing a salt…

Q21 · Some parts of a typical human chromosome are more numerous than others

Q22 · The enzyme telomerase prevents loss of telomeres after many mitotic cell cycles

Q23 · The diagram shows a cell during mitosis

Q24 · A gene codes for the production of a protein, p53, that binds to damaged DNA during…

Q25 · What is the role of DNA polymerase?

Q26 · Which row represents the correct features of the nitrogenous base thymine?

Q27 · Meselson and Stahl investigated DNA in bacteria

Q28 · The table shows the DNA triplet codes for some amino acids

Q29 · A group of students were asked to look at the photomicrograph of a cross-section of…

Q30 · Irrigating crop plants with water containing low concentrations of salt causes an…

Q31 · The photomicrograph shows a transverse section through part of a plant root

Q32 · The table shows some information about three blood vessels, P, Q and R, from a mammal

Q33 · Which row correctly identifies the locations in which a type of molecule or cell is…

Q34 · The graph shows the percentage saturation of haemoglobin with oxygen at different partial…

Q35 · How many layers of cell surface membrane separate an oxygen molecule in the air space of…

Q36 · Which biochemical is formed and what happens to the oxygen dissociation curve of adult…

Q37 · The diagram has been used to identify four infectious diseases

Q38 · How does penicillin affect bacteria?

Q39 · Growth factors are chemicals that stimulate a cell to divide

Q40 · What describes artificial active immunity?

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