Biology 9700/12 May/June 2019: question paper and mark scheme

Question

The actual length of a cell structure is 8 µm. Which steps are used to calculate the magnification of an electron micrograph of this cell structure? step 1 measure the length of the cell structure image on the micrograph in centimetres step 2 measure the length of the cell structure image on the micrograph in millimetres step 3 divide the image length by 1000 step 4 multiply the image length by 1000 step 5 divide by 8 step 6 multiply by 8 A steps 1, 3 and 6 B steps 1, 4 and 6 C steps 2, 3 and 5 D steps 2, 4 and 5

Question

What is the typical resolution of a microscope using daylight as a light source with a ×10 eyepiece lens and a ×40 objective lens? A 0.20 nm B 200 nm C 100 µm D 400 µm

Question

Two different types of cell, P and Q, were broken up using ultrasound and their contents analysed. Both types of cell contained small circular DNA. The circular DNA from P all carried the same base sequence, but those from Q were of two types, with different base sequences. What may be concluded about the identity of cell types P and Q? P Q A heart muscle fibres root cortical cells B lymphocytes mature red blood cells contaminated by bacteria C mature red blood cells phloem sieve tube element D root cortical cells leaf mesophyll cells

Question

Which features shown in the diagram can be present in viruses? 4 1 RNA DNA feature 3 2 70S protein coat ribosomes A 1, 2 and 3 B 1, 2 and 4 C 1, 3 and 4 D 2, 3 and 4

Question

After boiling a sample of milk with Benedict’s solution, a yellow colour is observed. Which conclusion about the sample of milk is correct? A Reducing sugars are not present. B Reducing sugars are present. C There is a high concentration of fructose. D There is a low concentration of sucrose.

Question

Which of the statements about polysaccharides can be used to describe amylose and cellulose? 1 contains 1,4 glycosidic bonds 2 contains 1,6 glycosidic bonds 3 polymer of glucose A 1 and 2 B 1 and 3 C 1 only D 2 and 3

Question

Which diagram shows the formation of a peptide bond? A B H H O H H O H H O O H H N C C N C C N C C C C N H H OH H H OH H H OH HO H H H2 O H 2O C D H H O H H O H H O O H H N C C N C C N C C C C N H H OH H H OH H H OH HO H H H 2O H 2O

Question

In enzyme-catalysed reactions, the position of the amino acids found at the active site is important. During the synthesis of enzymes, amino acids are brought together in the correct position to form the active site. Which levels of protein structure must be involved in forming the active site? level of protein structure primary secondary tertiary quaternary A key B = involved C = not involved D

Question

Which features affect the tensile strength of collagen? 1 the helical structure of collagen chains 2 the small R group of the amino acids in collagen 3 the insoluble nature of collagen 4 the bonds between collagen molecules A 1, 2, 3 and 4 B 1, 2 and 4 only C 1 and 3 only D 2, 3 and 4 only

Question

A fixed volume of the enzyme catalase was added to a fixed volume of hydrogen peroxide solution. The diagram shows how the concentration of product changed over the course of the reaction. concentration of product 0 0 time What explains the shape of this graph? A The active sites become saturated. B The enzyme was denatured. C The hydrogen peroxide inhibited the reaction. D The substrate molecules were used up.

Question

A fixed volume and concentration of substrate and enzyme were mixed. All other variables were kept constant. The enzyme-catalysed reaction was left until it was complete. Which graph shows how the rate of reaction changes with time? A B rate of rate of reaction reaction 0 0 0 time 0 time C D rate of rate of reaction reaction 0 0 0 time 0 time

Question

The fatty acids elaidic acid and oleic acid have exactly the same structural formulae, with one double bond in the chain. However, the shapes of the chains are different, as shown in the diagram. elaidic acid oleic acid COOH COOH Which row shows the effect of the presence of these fatty acids on the structure and behaviour of a cell surface membrane? elaidic acid oleic acid A does not fit closely with other fits closely with other fatty fatty acids so that the membrane acids so that the membrane is is less fluid at high temperatures less fluid at low temperatures B does not fit closely with other fits closely with other fatty fatty acids so that the membrane acids so that the membrane is is more fluid at low temperatures less fluid at low temperatures C fits closely with other fatty does not fit closely with other acids so that the membrane is fatty acids so that the membrane less fluid at high temperatures is more fluid at low temperatures D fits closely with other fatty does not fit closely with other acids so that the membrane is fatty acids so that the membrane more fluid at low temperatures is more fluid at high temperatures

Question

The diagram shows a cell surface membrane. X Y W Z Which is a correct role for a labelled molecule? A W is involved in controlling membrane stability. B X is involved in active transport. C Y is involved in cell signalling. D Z is involved in diffusion of ions.

Question

The diagram shows a simple cell signalling pathway in which a signal molecule leads to a response, such as a secretion. signal → P → Q → response molecule Which row identifies P and Q? P Q A activated enzyme in cytoplasm target in cell surface membrane B lipid in cell surface membrane extracellular enzyme C protein in cell surface membrane activated enzyme in cytoplasm D target in cytoplasm protein in cell surface membrane

Question

Three parts of a chromosome and their functions are listed. part function P1 centromere F1 holds the coils of DNA together P2 histone proteins F2 holds two chromatids together P3 telomere F3 prevents loss of genes Which part is matched with its correct function? A P1 and F1 B P2 and F1 C P2 and F3 D P3 and F2

Question

The enzyme telomerase prevents loss of telomeres after many mitotic cell cycles. Which cells need to transcribe telomerase enzyme? 1 cancer cells 2 stem cells 3 activated memory B-lymphocytes A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

The diagram shows some of the stages which take place during the cell cycle. 1 number of DNA molecules in cell doubles 4 stages 2 nuclear envelope during cell cell grows disappears cycle 3 chromosomes become visible Which two stages take place during interphase? A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Question

Which statement correctly describes the base pairing in a molecule of DNA? A The purine adenine forms bonds with the pyrimidine thymine. B The purine adenine forms bonds with the pyrimidine uracil. C The purine cytosine forms bonds with the pyrimidine guanine. D The purine guanine forms bonds with the pyrimidine thymine.

Question

Which statements about complementary base pairing are correct? 1 It allows translation to occur. 2 Purines and pyrimidines are the same size. 3 The base pairs are of equal length. 4 Uracil forms two hydrogen bonds with adenine. A 1, 2, 3 and 4 B 1, 3 and 4 only C 1 and 4 only D 2 and 3 only

Question

The diagram shows the possible organisation of DNA molecules after one replication. Which organisation is correct? one strand of DNA A B C D

Question

The diagram shows part of the DNA sequence of a gene and a mutated sequence of the same gene. normal DNA sequence ... CCG GAT TAT TGC GAG AAA TGG CAT TCT AGG ... mutated DNA sequence ... CCG GAT GTA TTG CGA GAA ATG CAT TCT AGG ... What are possible effects of the mutated sequence? 1 the presence of mRNA stop codons, UAG, UAA or UGA 2 a change in the sequence of amino acids 3 a non-functional protein 4 ribosomes cannot translate the mRNA A 1, 2 and 3 B 1, 3 and 4 C 1 and 4 only D 2 and 3 only

Question

What is correct for phloem sieve tube elements? A Companion cells provide structural support to the phloem sieve tube elements. B Lignified walls of phloem sieve tube elements prevent transport of mineral salts by mass flow. C Phloem sieve tube elements become narrower as movement of sucrose occurs. D Plasmodesmata allow movement of water and solutes across cell walls of phloem sieve tube elements.

Question

The diagrams show transverse sections of parts of a plant. Transport tissues are labelled 1 to 6. leaf stem root 3 1 4 5 6 2 Which combination shows the tissues that have a main function of transporting water? 1 2 3 4 5 6 A key B = transporting water is a main function C = transporting water is not a main function D

Question

The statements are descriptions of how water moves across the root to the xylem vessel elements. 1 Water enters cell walls. 2 Water enters cytoplasm by osmosis. 3 Water moves from cell to cell through plasmodesmata. 4 Water moves through cell walls. Which statements describe the apoplast pathway? A 1, 2, 3 and 4 B 1, 2 and 3 only C 1 and 4 only D 4 only

Question

Four plants, A, B, C and D, were grown in the same conditions and their transpiration rates measured. Which plant is most likely to be a xerophyte? transpiration A rate / mg cm–2 B C D 00:00 12:00 24:00 time of day / hours

Question

Sucrose moves from a mesophyll cell in a leaf into a phloem sieve tube element. Which changes to the water potential and the volume of liquid in the phloem sieve tube element are correct? water potential volume of liquid becomes A less negative decreases B less negative increases C more negative decreases D more negative increases

Question

The diagram shows a cross-section through a mammalian heart. W X Which chambers of the heart are represented by W and X? W X A left ventricle right ventricle B right atrium left atrium C right atrium right ventricle D right ventricle left ventricle

Question

At a certain point in a cardiac cycle, the pressure in the right ventricle is lower than that in the right atrium and lower than that in the pulmonary artery. Which row is correct? atrioventricular semilunar valve valve A closed closed B closed open C open closed D open open

Question

The diagram shows the pathway for the transport of carbon dioxide that occurs in red blood cells. CO2 1 H 2O 2 haemoglobin 3 4 Which row is correct? 1 2 3 4 A carbaminohaemoglobin haemoglobinic hydrogen ions hydrogencarbonate acid ions B carbonic anhydrase carbonic acid hydrogen ions hydrogencarbonate ions C carboxyhaemoglobin carbonic carbonic acid carbon dioxide anhydrase D haemoglobinic acid carbonic acid hydrogencarbonate hydrogen ions ions

Question

The diagram shows a transverse section through an artery. X Which statement describes the tissues present in layer X? A collagen and smooth muscle only B elastic fibres and collagen only C elastic fibres and smooth muscle only D elastic fibres, collagen and smooth muscle

Question

The large arteries close to the heart have a thick elastic layer in their walls. Which statements about this layer are correct? 1 helps to maintain the blood pressure in arteries 2 reduces friction within the arteries 3 prevents too much pressure bursting the artery wall A 1, 2 and 3 B 1 and 3 only C 1 only D 2 and 3 only

Question

Which tissues are present in the walls of a trachea and an alveolus? tissue epithelium with smooth goblet cells muscle A trachea alveolus key B trachea = present alveolus = absent C trachea alveolus D trachea alveolus

Question

The surface tension of the layer of liquid lining the alveoli tends to pull the walls inwards so alveoli could collapse. Which statements could explain how this is prevented? 1 Alveolar fluid is moved around by cilia. 2 Elastic fibres keep the alveoli open. 3 Epithelial cells secrete a chemical that reduces the cohesion in water. A 1 and 2 B 1 and 3 C 2 and 3 D 3 only

Question

The diagram shows some of the effects of nicotine and carbon monoxide in cigarette smoke. 2 1 3 carbon nicotine monoxide Which row is correct? 1 2 3 A increase in heart rate short-term effect on combines more readily with cardiovascular system haemoglobin than oxygen B increases diameter can cause combines irreversibly of small arteries chronic bronchitis with haemoglobin C reduces the oxygen short-term effect on reduces the blood carrying capacity of blood gas exchange system supply to hands and feet D stimulates goblet cells highly addictive increases risk to secrete more mucus of blood clotting

Question

Which row correctly identifies the causative organism of each disease? cholera measles smallpox tuberculosis A Variola Morbillivirus Vibrio Mycobacterium B Variola Mycobacterium Vibrio Morbillivirus C Vibrio Morbillivirus Variola Mycobacterium D Vibrio Mycobacterium Variola Morbillivirus

Question

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

Question

What is a social factor that affects the spread of malaria? A an increase in drug resistant forms of malaria B climate change C difficulty in producing a vaccine D migration of people because of wars

Question

Which are specific immune responses? 1 phagocytosis 2 production of antibodies 3 production of memory cells A 1 and 3 only B 1 only C 2 and 3 only D 2 only

Question

Newborn babies have natural passive immunity. What is correct for this type of immunity? immunity is antibodies are temporary broken down A key B = correct C = not correct D

Question

The diagrams show three different types of antibody structure. IgG IgA IgM Which row is correct? IgG IgA IgM A one binding site for two light chains two heavy chains an antigen molecule B two heavy chains four binding sites five hinge regions for antigen molecules C two hinge regions four heavy chains five light chains D two light chains four hinge regions ten binding sites for antigen molecules