Biology 9700/12 October/November 2022: question paper and mark scheme

Question

The diagram shows a stage micrometer, with divisions 0.10 mm apart, viewed through an eyepiece containing a graticule. 0 10 20 30 40 50 60 70 80 90 10 The area of the field of view of the microscope can be calculated using this formula. area = πr2 A student calculated the area of the field of view of the microscope using the information provided and a value for π of 3.142. Which answer has been rounded correctly to an appropriate number of significant figures? A 0.04909 mm2 B 5 × 10–2 mm2 C 4.909 × 104 µm2 D 4.91 × 104 µm2

Question

Where are cisternae found in a cell? 1 endoplasmic reticulum 2 Golgi body 3 mitochondria A 1 and 2 B 1 and 3 C 1 only D 2 and 3

Question

Which row matches the functions to the cell structures? vacuole nucleolus ribosomes lysosomes A stores water, manufactures protein involved in cell sugar and messenger RNA synthesis recognition pigment B exports proteins manufactures lipid synthesis involved in cell ribosomal RNA recognition C stores water, manufactures protein contains sugar and ribosomal RNA synthesis enzymes pigment D exports proteins manufactures lipid synthesis contains messenger RNA enzymes

Question

Which structures are found in prokaryotes and eukaryotes? A cell membrane and nucleus B cell membrane and ribosomes C nucleus and mitochondria D mitochondria and ribosomes

Question

Which molecules are present in all viruses? 1 thymine 2 adenine 3 cytosine A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

The table shows the observations recorded from tests for biological molecules on four samples, A, B, C and D. Which conclusion is correct? Benedict’s biuret iodine conclusion solution reagent solution A blue blue blue-black contains starch only B blue purple orange contains reducing sugar only C green blue orange contains reducing sugar and protein D red blue blue-black contains starch and protein

Question

The diagrams show some biological molecules. Which biological molecule forms a polymer with a structural role in plants? A B CH2OH H C O H C OH H H H C C H C OH OH H HO OH C C H C OH H OH H C D NH2 CH2OH N C O N H OH H C C HO OH H N N HO H O C C C C H OH C C OH OH

Question

Which molecule is a disaccharide and a reducing sugar? A fructose B glucose C maltose D sucrose

Question

The diagram shows bonding in part of a polysaccharide. CH2OH O H OH O X OH CH2OH CH2OH CH2 CH2OH O H O H O H O H OH OH OH OH O O O OH OH OH OH Which type of glycosidic bond is shown at position X? A α-1,4 B α-1,6 C β-1,4 D β-1,6

Question

Which statements about triglycerides and phospholipids are correct? 1 Fatty acids in a triglyceride may be saturated or unsaturated but in a phospholipid they are always saturated. 2 Triglycerides and phospholipids both have a hydrophobic region. 3 Triglycerides are non-polar molecules and phospholipids are polar molecules. A 1 and 2 B 1 only C 2 and 3 D 3 only

Question

Silk moth caterpillars have been genetically modified to produce a mixture of their own silk and the much stronger spider silk of the golden orb web spider. The spider silk polypeptide chain has many repeated sequences of two amino acids, glycine and alanine, arranged in a crystalline structure. What correctly describes the structure of spider silk? A primary protein structure with regions of α-helices B secondary protein structure with regions of β-pleated sheets C tertiary protein structure with regions of α-helices D quaternary protein structure with regions of β-pleated sheets

Question

Which property of the tertiary structure of a globular protein enables it to catalyse a metabolic reaction? A It has hydrophobic amino acid R groups on the outside. B It will be denatured by high temperatures. C The R groups of some amino acids form bonds with a substrate. D The three-dimensional shape depends on hydrogen bonding.

Question

A student investigated the effect of substrate concentration on the activity of an enzyme. The graph shows the results of this investigation. X activity of enzyme substrate concentration An increase in which factors could lead to a change in the activity of the enzyme at point X on the graph? 1 pH 2 substrate concentration 3 temperature A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

The Michaelis–Menten constant, Km, is the substrate concentration at which an enzyme works at half its maximum rate. What is correct when the Km value is low? A The enzyme has a low affinity for the substrate and the quicker the reaction will proceed to its maximum rate. B The enzyme has a low affinity for the substrate and the slower the reaction will proceed to its maximum rate. C The enzyme has a high affinity for the substrate and the quicker the reaction will proceed to its maximum rate. D The enzyme has a high affinity for the substrate and the slower the reaction will proceed to its maximum rate.

Question

Which functions are performed by glycoproteins on the surface of a cell surface membrane? 1 to act as enzymes catalysing reactions in the membrane 2 to have a specific site where chemicals can bind 3 to secrete specific chemicals used for cell signalling A 1, 2 and 3 B 2 and 3 only C 2 only D 3 only

Question

The diagram represents a process by which molecules move out of a cell through a cell surface membrane. Which process does this represent? A exocytosis B diffusion C facilitated diffusion D osmosis

Question

The photomicrograph shows the appearance of onion epidermal cells after they have been soaked in solution X for one hour. Y What fills the space labelled Y? A air B cytoplasm C solution X D water

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

Which processes that occur in the cell cycle are represented in the diagram? 4 3 mass of nuclear DNA in a cell 2 / arbitrary units 1 0 time A DNA replication and nuclear division only B DNA replication, nuclear division and cytokinesis C mitosis and cytokinesis D mitosis only

Question

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 the gene coding for the p53 protein, preventing production of the protein. Which statement explains why this mutation may cause cancer? A Cells with no p53 are able to undergo mitosis. B Cells with no p53 replicate their damaged DNA. C The carcinogen in cigarette smoke increases the rate of cell division. D The mutated p53 causes uncontrolled cell division.

Question

Stained onion cells undergoing mitosis were observed using a microscope. Which row is correct for mitosis in plant cells? prophase metaphase anaphase telophase A centrioles chromosomes pair two telomeres are two nuclear visible up at the equator visible on each membranes form chromatid B centromeres chromosomes align chromosomes centrioles present at the equator replicate to disappear form chromatids C each chromosome centromeres attach chromatids separate chromosomes is visible as two to spindle fibres and migrate decondense chromatids to opposite poles D spindle fibres formed centromeres attach chromatids are spindle fibres by centrioles to spindle fibres pulled apart form new nuclear by centrioles membranes

Question

How many statements about semi-conservative replication of DNA in a eukaryotic cell are correct? 1 The process takes place in the cytoplasm. 2 An adenine nucleotide will line up against uracil on the template strand. 3 Each daughter molecule will contain half of the original DNA molecule. 4 If the DNA molecule contained 40% guanine nucleotides, each daughter molecule will contain 20% guanine nucleotides. A 1 B 2 C 3 D 4

Question

A section of the polypeptide coding for the haemoglobin β-chain contains the following amino acids. – Pro – Glu – Glu – Patients with sickle cell anaemia have mutated β-polypeptide chains. The section of the mutated polypeptide contains the following amino acids. – Pro – Val – Glu – The table shows the possible anticodons for Val. amino acid anticodon Val CAA Val CAG Val CAC Val CAU What is the corresponding DNA triplet code for the substituted amino acid in the mutated polypeptide? A GTT B GAC C CTC D CAT

Question

Which diagram correctly represents temporary hydrogen bonding during transcription? A B C D A U C G G C T U

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

The electron micrograph shows a longitudinal section through part of a plant stem. X What is X? A xylem vessel element B stem cell C phloem sieve tube element D companion cell

Question

Sodium chloride is added to a culture solution containing freshwater single-celled plant cells. What happens to the water potential of the culture solution when the sodium chloride is added and what may happen to the plant cells after 5 minutes? water potential of the single-celled plant cells culture solution when after 5 minutes sodium chloride added A becomes less negative become plasmolysed B becomes less negative become turgid C becomes more negative become plasmolysed D becomes more negative become turgid

Question

Which statements correctly describe transport pathways in dicotyledonous plants? 1 In the apoplast pathway, water may move through plasmodesmata. 2 In the symplast pathway, water may move through intercellular spaces. 3 The apoplast pathway may be blocked by the Casparian strip. A 1 and 2 B 1 and 3 C 2 and 3 D 3 only

Question

Which statement about the movement of water from roots to leaves is not correct? A A continuous column of water is partly maintained by the attraction of water molecules to cellulose. B Hydrogen bonding between water molecules enables mass flow of water. C Hydrostatic pressure in xylem vessel elements is higher in roots than in leaves. D Water potential changes throughout the length of the xylem vessel elements.

Question

Which terms describe the method by which water is transported within xylem vessel elements? 1 cotransport 2 cohesion-tension 3 osmosis A 1 and 2 B 1 and 3 C 2 only D 3 only

Question

What is the main function of a companion cell in phloem tissue? A providing cytoplasmic contact with the sieve tube element for loading B providing structural support for the sieve tube element C providing the nucleus for cell division in the phloem D providing the source of assimilates for storage

Question

The photomicrograph shows a blood smear. Which cell is a monocyte? B A C D

Question

The table shows some information about three blood vessels, P, Q and R, from a mammal. wall percentage composition of wall diameter thickness elastic / mm muscle collagen / mm tissue 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

Question

Ventricular septal defect (VSD) is a heart defect that people can have from birth. People with VSD have a hole in the wall (septum) that separates the left and right ventricles. What could happen in a person with VSD? 1 Blood will leak through the hole, mostly from right to left. 2 The volume of blood circulating through the lungs will be higher than in a person without VSD. 3 Less oxygen will be delivered to the body tissues. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

Which statement about the structure of the heart is correct? A The semilunar valves close when the pressure in the ventricles falls lower than the pressure in the arteries. B A muscle called the septum separates the atria from the ventricles. C There is a small patch of tissue in the right atrium that acts to delay the electrical impulse. D Closure of valves in the veins prevents backflow of blood into the ventricles.

Question

What can be found in the wall of an alveolus in the lungs of a human? elastic cartilage cilia fibres A key B = present C = not present D

Question

What are the functions of cilia in the gas exchange system? 1 to move mucus 2 to trap pathogens and dust 3 to increase the surface area 1 2 3 A key B = a function C = not a function D

Question

Cholera and tuberculosis are infectious diseases that can spread when people have to live in overcrowded conditions. Which strategies would help control the spread of cholera and tuberculosis? 1 covering food to prevent flies landing on it 2 providing chlorinated drinking water 3 treating severe cases with antibiotics A 1, 2 and 3 B 1 only C 2 and 3 only D 3 only

Question

Immunity to certain pathogens develops when a person is given a vaccination. Which effects of vaccination are correct? 1 production of antibodies to protect against future infections 2 results in artificial active immunity 3 stimulation of appropriate lymphocytes A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

A student wrote three statements about antibodies. 1 Their structure depends on peptide, hydrogen and disulfide bonds. 2 They are protein molecules with both tertiary and quaternary structure. 3 Four polypeptides provide four antigen binding sites. Which statements are correct? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only