Biology 9700/11 May/June 2023: question paper and mark scheme

Question

The electron micrograph shows onion root cells prepared using a freeze-fracture technique. The cells were quickly frozen and then physically broken apart. Freeze fracture breaks apart cells along weak areas, such as membranes and the surfaces of organelles. structure X ×20 000 Which statement best explains the appearance of the electron micrograph? A The cells were broken apart at the endoplasmic reticulum; structure X is a ribosome. B The cells were broken apart at the nuclear envelope; structure X is a nuclear pore. C The cells were broken apart at the nuclear envelope; structure X is a ribosome. D The cells were broken apart at the tonoplast; structure X is a plasmodesma.

Question

Which cell structures can form vesicles? cell surface endoplasmic Golgi body membrane reticulum A key B = can form vesicles C = cannot form vesicles D

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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 synthesis of polypeptides 2 synthesis of lipids 3 packaging of hydrolytic enzymes that will remain in the cell 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 W V Z B W Z Y C Z W Z D Z V W

Question

Which cells contain a tonoplast? sieve tube root hair companion endodermis element A key B = contain tonoplast C = do not contain tonoplast D

Question

Which organelles found in animal or plant cells are surrounded by double membranes? A chloroplasts, mitochondria, vacuoles B chloroplasts, mitochondria, nuclei C chloroplasts, nuclei, vacuoles D mitochondria, nuclei, vacuoles

Question

Some scientists think that mitochondria evolved from bacteria that entered the cytoplasm of a different cell and were able to survive there. Which structural features of mitochondria support this hypothesis? folded internal circular DNA 70S ribosomes membrane A key B = supports C = does not support D

Question

What is present in all viruses, all prokaryotes and all eukaryotes? A ribose B deoxyribose C cytosine D thymine

Question

The table shows some steps that can be made in carrying out the Benedict’s test. Which combination of steps is required to carry out a semi-quantitative test on a reducing sugar solution? standardise boiling standardise volume boil with time with Benedict’s of Benedict’s hydrochloric acid solution and solution and volume and then neutralise compare final colour of test solution with alkali with numbered colour standards A key B = step made C = step not made D

Question

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

Question

Insulin is a globular protein involved in cell signalling. It is transported in the blood plasma from the cells that synthesise it to its target cells. A molecule of insulin contains six sulfur-containing amino acids and has two polypeptide chains. Which statements about insulin are correct? 1 An insulin molecule has a quaternary structure. 2 Insulin polypeptides are held together by six disulfide bonds. 3 Amino acids with hydrophobic R groups would be found in the centre of an insulin molecule. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

Which statement correctly explains why blood plasma can be maintained at a stable temperature? A It has a low specific heat capacity. B It has a high specific heat capacity. C It has a low latent heat of vaporisation. D It has a high latent heat of vaporisation.

Question

Which region on the graph shows the activation energy of an enzyme-catalysed reaction? A C B energy of molecules in a reaction without D with enzyme enzyme time

Question

The graph shows the effect of an increasing substrate concentration on the rate of an enzyme-catalysed reaction. maximum rate of reaction rate of reaction P Q substrate concentration Line P represents the result when the enzyme is used at its optimum pH and optimum temperature and without an inhibitor. Line Q represents the result when the reaction conditions are changed. Which descriptions of changes to the reaction conditions could result in line Q if all other conditions were kept the same? 1 Add an inhibitor that attaches to a site other than the active site. 2 Add an inhibitor that has a similar shape to the substrate. 3 Add an inhibitor that blocks the active site of the enzyme. 4 Carry out the reaction at a higher temperature. A 1, 3 and 4 B 1 and 4 only C 2, 3 and 4 D 2 and 3 only

Question

Which statement about cell signalling is correct? A One type of receptor molecule will recognise all ligands in the body. B The binding of a ligand may cause a change to the shape of the receptor. C The receptors for ligands are always found on the inside of cells. D The same ligand is made by all of the cells in the body.

Question

Four students, A, B, C and D, observed plant epidermal cells that had been placed in a concentrated sucrose solution for 30 minutes. They were asked to identify the partially permeable layer and to explain the appearance of the cells in terms of water potential and movement of water. Which student is correct? partially water potential movement of water permeable layer at start of experiment during experiment A cell surface cell contents have a lower water moved out of the cell membrane water potential than the and no water moved in sucrose solution B cell surface cell contents have a higher more water moved out membrane water potential than the of the cell than moved in sucrose solution C cell wall cell contents have a lower more water moved out water potential than the of the cell than moved in sucrose solution D cell wall cell contents have a higher water moved out of the cell water potential than the and no water moved in sucrose solution

Question

The table compares the surface area to volume ratios of five agar blocks that differ in dimensions but which all have the same volume. The agar blocks can be used to measure the efficiency of diffusion, where efficiency is measured as the time taken for a dye to reach all parts of the block. length width height surface volume surface area : / mm / mm / mm area / mm2 / mm3 volume ratio 1 8 8 8 384 512 0.75 2 16 16 2 640 512 1.3 3 32 4 4 544 512 1.1 4 32 32 0.5 2112 512 4.1 5 64 4 2 784 512 1.5 Which prediction can be made about the way in which size and dimensions of these blocks affect the efficiency of diffusion? A The efficiency of diffusion will decrease as the width of a block increases. B The efficiency of diffusion will increase as the height of a block increases. C The efficiency of diffusion will increase as a block of fixed volume is flattened. D The efficiency of diffusion will decrease as a block of fixed volume is elongated.

Question

The cell cycle includes mitosis. What are features of this type of nuclear division? 1 forms cells of equal size to the parent cell 2 forms genetically identical nuclei 3 semi-conservative replication of DNA A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 only

Question

A student observed the cells in the growing region (meristem) of an onion root and obtained the data shown. number stage of cells interphase 886 prophase 73 metaphase 16 anaphase 14 telophase 11 Which percentage of cells contains chromosomes that appear as two chromatids? A 7.3% B 8.9% C 95.9% D 97.5%

Question

Which statement about messenger RNA is correct? A In eukaryotic cells, mRNA is made by removing exons from the primary RNA transcript. B mRNA is a single-stranded polynucleotide containing a different purine base than DNA. C mRNA molecules contain ribose sugars joined to phosphate groups by phosphodiester bonds. D The monomers of mRNA contain a phosphate group, deoxyribose sugar and a nitrogenous base.

Question

Which structures are involved in transcription only? DNA template RNA anticodons strand polymerase A key B = involved C = not involved D

Question

One gene provides the code for the production of which type of molecule? A amino acid B DNA C nucleotide D polypeptide

Question

The table shows some mRNA codons that code for certain amino acids. mRNA codon amino acid GCG, GCA, GCC, GCU alanine ACG, ACA, ACC, ACU threonine UGC, UGU cysteine UAC, UAU tyrosine CAG, CAA glutamine CGG, CGA, CGC, CGU arginine A DNA template strand has the base sequence shown. ACAGTATTATTTGCAACG What would the change in the amino acid be if the first base in the fifth DNA triplet was substituted for an A base? A alanine to cysteine B alanine to threonine C arginine to cysteine D arginine to threonine

Question

Which structures contain cytoplasm with mitochondria and a nucleus? xylem vessel element B companion phloem cell A D C sieve tube element

Question

What is the correct term to describe intermolecular hydrogen bonding between water molecules? A adhesion B cohesion C osmosis D diffusion

Question

The diagram shows the outline of a xerophytic leaf that had been left for 45 minutes in different conditions, P and Q. Y Y P Q Which statements about the cells in layer Y of the leaf in each of the conditions P and Q after 45 minutes are correct? 1 There is a less negative water potential in P than in Q. 2 The cells may be turgid in P and plasmolysed in Q. 3 The cells are less turgid in P than in Q. 4 There is no net diffusion of water into Y in either P or Q. A 1, 2 and 4 B 1, 3 and 4 C 1 and 3 only D 2 and 4 only

Question

How does sucrose move from chloroplasts to the phloem? 1 diffusion 2 apoplast pathway 3 symplast pathway A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

How are companion cells involved in loading sucrose into phloem sieve tube elements? A actively through cotransporter proteins and passively through plasmodesmata B actively through cotransporter proteins and plasmodesmata C passively through cotransporter proteins only D actively through plasmodesmata only

Question

The photomicrograph shows blood cells as seen using a high-power light microscope. 1 3 2 Which row correctly identifies the different types of white blood cell? 1 2 3 A lymphocyte monocyte neutrophil B monocyte neutrophil macrophage C neutrophil monocyte lymphocyte D phagocyte lymphocyte monocyte

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Plan diagrams of two blood vessels are shown. fatty tissue 3 4 5 1 2 Which labels are correct? 1 2 3 4 5 A aorta vena cava elastic smooth epithelium fibres muscle B artery vein collagen smooth endothelium fibres muscle and elastic tissue C vein artery collagen elastic squamous fibres fibres cells D coronary coronary elastic smooth epithelium artery vein fibres muscle and elastic tissue

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What are found in blood and tissue fluid? 1 carbon dioxide 2 fatty acids 3 white blood cells 4 proteins A 1, 2, 3 and 4 B 1, 2 and 3 only C 1, 2 and 4 only D 3 and 4 only

Question

Which reactions would be slowed down by an inhibitor of carbonic anhydrase? 1 CO2 + haemoglobin → carbaminohaemoglobin 2 CO2 + H2O → H2CO3 3 H2CO3 → H+ + HCO3– A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

Which sequence of letters correctly identifies the order of events during the cardiac cycle? T atrial walls contract U impulse is delayed by a fraction of a second V wave of excitation enters the atrioventricular node W wave of excitation passes down the Purkyne tissue X wave of excitation spreads from the sinoatrial node Y ventricles contract A B C D V X V X Y W T U T U Y V X U W V X W W T T Y Y U

Question

The diagram gives information about blood pressure in the left side of the heart during the cardiac cycle. 3 pressure key 2 aorta / kPa atrium ventricle 1 4 0 0.1 0.2 0.3 0.4 0.5 0.6 time / s Valves open and close at the points numbered. Which row identifies the valves opening or closing at the points numbered? atrioventricular semilunar atrioventricular semilunar valve opens valve opens valve closes valve closes A 1 3 4 2 B 2 4 3 1 C 3 1 2 4 D 4 2 1 3

Question

A person with no breathing conditions rests for an hour. Their breathing in this time is shallow and slow, so little air from outside the body reaches the alveoli. The person’s heart rate remains constant. Which statement is correct? A The carbon dioxide concentration in the blood in the pulmonary vein will be higher than in the pulmonary artery. B Carbon dioxide molecules in the air of the alveoli move out of the blood by active transport. C The air in the alveoli has a lower concentration of oxygen than the blood in the pulmonary vein. D Oxygen molecules diffuse from the air in the alveoli into the blood at a slower rate than when the person is active.

Question

Which statements about all bronchioles are correct? 1 They have epithelium. 2 They have goblet cells. 3 They have muscle tissue. A 1, 2 and 3 B 1 and 3 only C 2 only D 3 only

Question

The diagram shows some of the pathogens that cause disease in humans and some of the ways they are transmitted. 1 2 W bacterium protoctist contaminated water pathogen method of transmission 3 X Y virus mosquito bite coughs and sneezes What is the correct pathogen and method of transmission for malaria? A 1 and X B 2 and W C 2 and X D 3 and Y

Question

Some of the processes which result in the formation of a population of bacteria that are resistant to a new antibiotic are listed. 1 change in reproductive success of bacteria 2 increase in frequency of the resistance allele in the population 3 increase in genetic variation within the population 4 random mutation occurs in bacterial DNA What is the correct order of these processes? A 1→3→2→4 B 2→1→3→4 C 3→4→1→2 D 4→3→1→2

Question

When bacteria are grown in a Petri dish containing discs with antibiotics, there will be zones of inhibition of bacterial growth. antibiotic disc zone of inhibition area of bacterial growth The chart shows the size of the zones of inhibition when a species of bacteria was incubated on five different plates of agar, each containing a disc with a different antibiotic. 30 25 20 zone of inhibition 15 / mm 10 5 0 1 2 3 4 5 antibiotic Which conclusions can be made about the most and least effective antibiotics on this species of bacteria? most effective least effective antibiotic antibiotic A 3 2 B 4 3 C 3 1 D 2 3

Question

Which blood cell type does not recognise, engulf and digest non-self particles? A macrophages B neutrophils C phagocytes D T-killer cells

Question

Repeated infections with malaria result in more effective immunity to malaria. Which type of immunity is responsible for the more effective immunity? A artificial active B artificial passive C natural active D natural passive