Biology 9700/13 May/June 2021: question paper and mark scheme

Question

Which set of measurements is correct? thickness of cell diameter of diameter of red surface membrane capillary blood cell of red blood cell A 7 μm 7 μm 7 nm B 7 μm 7 nm 7 nm C 0.7 mm 7 μm 7 nm D 0.7 mm 0.7 mm 7 μm

Question

The diagram shows an eyepiece graticule and part of a stage micrometer scale as seen using ×100 magnification. eyepiece graticule stage micrometer scale 0.1 mm Which is the correct method for calculating the value of one eyepiece graticule unit in micrometres (μm)? A divide 100 by 0.1 then multiply by 1000 B divide 100 by 0.1 then multiply by 1000 divided by 100 C multiply 0.1 by 1000 then divide by 100 D multiply 0.1 by 1000 then divide by 100 then divide again by 100

Question

A prokaryotic cell, 1 μm in diameter, is magnified 50 000 times on an electron micrograph. What is the diameter as shown in the electron micrograph? A 0.5 mm B 5 mm C 50 mm D 500 mm

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Which cell structures contain DNA? 1 mitochondria 2 chloroplasts 3 centrioles 4 nucleolus A 1, 2 and 3 B 1, 2 and 4 C 1, 3 and 4 D 2, 3 and 4

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Four students were asked to match the function with the appearance of some cell structures in an animal cell. The functions were listed by number. 1 mRNA passes through to the ribosome 2 synthesis of polypeptides 3 synthesis of lipids The appearances were listed by letter. V membranes which surround an enclosed inner cavity W non-membrane bound, spherical structures X a double membrane interspersed with pores Y non-membrane bound, cylindrical structures Z membrane-bound sacs, arranged as a flattened stack Which student correctly matched the numbered function with the appearance of the cell structure? 1 2 3 A V X Z B V Z W C X W V D X Z V

Question

Which row is correct for structures found in eukaryotic cells? circular DNA 70S ribosomes 80S ribosomes A present present present B present present absent C present absent present D absent present absent

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Four solutions were tested for the presence of four different biological molecules. The appearance of the solutions after each test are shown in the table. Benedict’s solution following acid Benedict’s biuret emulsion hydrolysis 1 blue blue purple cloudy 2 green blue purple clear 3 red green purple cloudy 4 yellow yellow blue clear Which solutions contained molecules with ester bonds? A 1, 2 and 3 B 1 and 3 only C 2, 3 and 4 D 2 and 4 only

Question

The diagrams represent two monosaccharides with the same molecular formula (C6H12O6). Both can exist in an alpha (α) or beta (β) form as shown. CH2OH CH2OH CH2OH CH2OH C O C O C O C O HO OH H OH HO H H H H H H H C C C C C C C C OH H OH H OH H OH H H H HO H H OH HO OH C C C C C C C C H OH H OH H OH H OH β-galactose β-glucose α-galactose α-glucose The diagram shows a lactose molecule formed by condensation between glucose and galactose. CH2OH CH2OH O O HO H OH H H O OH H OH H H H H H OH H OH Which molecules have condensed to form lactose? A α-glucose and α-galactose B α-glucose and β-galactose C β-glucose and α-galactose D β-glucose and β-galactose

Question

One type of covalent bond between two monomers is shown. CH2OH O H H H OH H ...O O CH2 H OH O H H H OH H ...O O... H OH Which molecules contain this type of covalent bond? A amylopectin, amylase, glycogen and starch B amylopectin, amylase and glycogen only C amylopectin, glycogen and starch only D amylase, glycogen and starch only

Question

Which statements about carbohydrates and triglycerides are correct? 1 They form polymers. 2 They contain carbon, hydrogen and oxygen. 3 They are used as energy stores. A 1, 2 and 3 B 1 and 3 only C 1 only D 2 and 3 only

Question

Which molecules contain at least three double bonds? A saturated fatty acid, collagen and haemoglobin B collagen and saturated fatty acid C haemoglobin and collagen D saturated fatty acid and haemoglobin

Question

The diagrams show the structures of two amino acids. One contains two amino (–NH2) groups, labelled 1 and 2. The other contains two carboxylic (–COOH) groups, labelled 3 and 4. 2 3 H 2N CH COOH H 2N CH COOH CH2 CH2 C 1 COOH 4 O NH2 A peptide bond is formed between the two amino acids. Which groups form the peptide bond? A 1 and 4 B 2 and 3 C 2 and 4 D 1 and 3

Question

Which row about the structure of proteins is correct? primary structure secondary structure tertiary structure quaternary structure A is the number is the right-handed is the result of is the sub-unit of amino acids spiral formed by the cross-bonding polypeptides that present in a protein primary structure between specific link together to amino acids in form a protein the primary structure B is the order of is the coiling of a is the shape formed contains two types amino acids present chain of amino acids by the folding of a of polypeptide that in a protein to form a β-pleated polypeptide and is interact forming the encoded by DNA sheet or an α-helix held together by shape of a protein hydrogen bonds C is the result of occurs because of an is the result of ionic is formed by four translation of an attraction between and hydrogen bonds, polypeptides and mRNA molecule by hydrogen and disulfide bridges an additional a ribosome into a oxygen atoms in and hydrophobic reactive group chain of amino acids the peptide bonds interactions between attached to the amino acids protein D is the sequence is formed by is formed as a result is formed by the of amino acids in hydrogen bonding of interaction of the linking together a protein coded by between amino acids side chains of of more than one an mRNA molecule forming the amino acids in the polypeptide to primary structure primary structure form a protein

Question

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

Question

An investigation was carried out on the effect of temperature on the activity of an enzyme when it is immobilised and when it is non-immobilised (free in solution). The product of the enzyme- catalysed reaction causes a decrease in pH. The graph shows the results of the investigation. key non-immobilised, 75 °C pH immobilised, 75 °C immobilised, 37 °C non-immobilised, 37 °C time Which would give the highest yield of product? A immobilised, 37 °C B immobilised, 75 °C C non-immobilised, 37 °C D non-immobilised, 75 °C

Question

An indicator mixed with agar forms a pink colour. The pink-coloured agar becomes colourless when put in acid. Blocks of pink-coloured agar are cut to different sizes and put in acid. All other variables are kept constant. Which block becomes colourless most quickly? A 3 mm × 30 mm × 30 mm B 6 mm × 6 mm × 6 mm C 6 mm × 12 mm × 12 mm D 12 mm × 12 mm × 12 mm

Question

Three identical plant cells were put into one of three different concentrations of sugar solution, 10%, 5% and 2.5%. The cells were left for 50 minutes and then observed using a light microscope. cell X cell Y cell Z vacuole Which statement is not correct? A Cell X has the same water potential as the sugar solution it was put into. B Cell Y is turgid and cell Z is plasmolysed. C Cell Y was put into the 2.5% sugar solution. D Cell Z had a more negative water potential than the sugar solution it was put into.

Question

How many copies of each different DNA molecule are found in a cell at the start of each of these stages of the mitotic cell cycle? G2 of prophase cytokinesis interphase A 1 1 2 B 1 2 1 C 2 1 2 D 2 2 2

Question

Hydra are simple animals which can reproduce asexually. The photomicrograph shows an adult hydra with a new hydra developing while attached to the side of the adult animal. Which processes have occurred in the two hydra? 1 DNA replication 2 growth 3 mitosis A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

The diagram represents a nucleotide containing thymine. base Which statements about this nucleotide are correct? 1 Thymine is a pyrimidine. 2 Base pairing occurs with two hydrogen bonds. 3 The carbohydrate can be ribose or deoxyribose. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

Some of the events that occur during transcription are listed. 1 Bonds break between complementary bases. 2 Bonds form between complementary bases. 3 Sugar-phosphate bonds form. 4 Free nucleotides pair with complementary nucleotides. Before the mRNA molecule leaves the nucleus, which events occur twice during transcription? A 1, 2 and 3 B 1, 3 and 4 C 2, 3 and 4 D 1 and 2 only

Question

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 cysteine ACA proline GGA cysteine ACG proline GGC STOP ATC valine CAC The base sequence on the DNA template 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 a polypeptide with one different amino acid? 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 GCC

Question

A gene codes for the sequence of amino acids in a single polypeptide. Haemoglobin consists of two α-globins and two β-globins. How many genes are needed to code for a single haemoglobin molecule? A 1 B 2 C 4 D 8

Question

Which properties of water molecules are important in the upward flow of water through the xylem? 1 Water molecules are attracted to each other by hydrogen bonding. 2 Water molecules are attracted to cellulose by adhesion. 3 Water molecules have high cohesion in water columns. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

The graph shows the rate of water absorption and the rate of water loss by a plant during one 24-hour period. The plant was growing in natural conditions. water loss rate of water absorption or loss water absorption 0 00:00 04:00 08:00 12:00 16:00 20:00 24:00 night day night time What may be concluded from the graph? 1 The rate of water absorption and the rate of water loss peak at 16:00. 2 The rate of water loss is greater than the rate of water absorption for 12 hours. 3 The rate of water absorption is greater than the rate of water loss at night. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

Which statements explain why a stem is cut under water and connected to a potometer under water? 1 to prevent plasmolysis of xylem vessel elements 2 to prevent the collapse of xylem vessel elements 3 to prevent air entering xylem vessel elements A 1, 2 and 3 B 2 and 3 only C 1 only D 3 only

Question

Sucrose moves into an actively dividing shoot tip from 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

Sucrose is loaded into phloem sieve tubes from companion cells. What is the correct order of statements that explains this mechanism? 1 Hydrogen ions diffuse into companion cells through co-transporter proteins. 2 Hydrogen ions are pumped out of companion cells by active transport. 3 Sucrose diffuses into phloem sieve tubes via plasmodesmata. 4 Sucrose is co-transported along with hydrogen ions. A 1→2→4→3 B 1→4→2→3 C 2→1→4→3 D 4→1→2→3

Question

Which components are found in arteries? collagen A C B smooth endothelium D muscle

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Which diagram correctly shows the direction of the flow of blood through the heart? A B C D

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Which row correctly identifies the pulmonary artery? thickness of blood oxygen content of blood vessel wall / mm blood inside vessel pressure / mmHg A 1.30 deoxygenated 15–30 B 2.10 oxygenated 80–120 C 0.15 oxygenated 5–15 D 0.20 deoxygenated 3–8

Question

What is found in all blood vessels, lymph and tissue fluid? 1 carbon dioxide 2 glucose 3 white blood cells 4 antibodies A 1, 2, 3 and 4 B 1, 2 and 3 only C 1, 3 and 4 only D 2 and 4 only

Question

At high altitudes, the oxygen content of the air may be a third of that at sea level. As a person slowly climbs a mountain, their body gradually adjusts to the high altitude. What is increased during this period of adjustment? A the concentration of haemoglobin in the red blood cells B the oxygen-carrying capacity of the haemoglobin C the number of red blood cells per mm3 of blood D the rate at which haemoglobin releases oxygen into the tissues

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Which row correctly shows features present in terminal bronchioles? smooth cartilage cilia muscle A key B = present C = not present D

Question

The photomicrograph shows a section through lung tissue. Which structures are present in this photomicrograph? artery vein bronchus trachea A key B = present C = not present D

Question

The symptoms of two diseases are listed. disease 1 disease 2 coughing up blood shortness of breath pain when breathing difficulty breathing out loss of weight fatigue Which row identifies diseases 1 and 2? disease 1 disease 2 A chronic bronchitis emphysema B emphysema lung cancer C lung cancer chronic bronchitis D lung cancer emphysema

Question

Disease transmission can be reduced in different ways. antibiotic therapy for sufferers vaccination for non-sufferers more living space per person The transmission of which disease can be reduced by all of these methods? A cholera B TB C malaria D measles

Question

What do pathogens of HIV / AIDS, malaria and TB have in common? cell surface genes ribosomes membrane A key B = common to all three pathogens C = not common to all three pathogens D

Question

The diagram shows the immune response following infection by a virus. activated cells F activated cell chemical stimulation E H G host cell infected with virus secretion of antibodies Which row identifies the cells labelled E, F, G and H? E F G H A B-memory cell T-helper cell T-killer cell plasma cell B B-memory cell T-memory cell macrophage plasma cell C plasma cell T-memory cell T-helper cell B-memory cell D T-killer cell B-memory cell macrophage T-helper cell

Question

Monoclonal antibodies are used to test for the presence of the hormone HCG in the urine of a human female during early pregnancy. Which statements describe how the monoclonal antibodies used in this test are produced? 1 HCG is injected into a mouse, and plasma cells in the mouse produce antibodies specific to HCG. 2 Antibodies are extracted from the mouse and then fused with cancer cells to produce hybridoma cells. 3 Single hybridoma cells are cultured and they divide by mitosis to produce a clone of hybridoma cells. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only