Biology 9700/14 May/June 2025: question paper and mark scheme

Question

Plant cells are stained and then viewed with a simple light microscope, using daylight as the only light source. Which cell structures are clearly visible at a magnification of × 400? A chloroplast grana B lysosomes C nucleoli D ribosomes

Question

The diagram shows an image of a cell with a scale bar. The scale bar (Z) represents an actual size of 15 μm. Distance Y represents the diameter of the cell image. Y Z Which calculation to find the actual diameter of the cell is correct? A 15 × (Y + Z) Z B Y× 15 Y C × 15 Z Y D 15

Question

The diagram shows a stage micrometer, with divisions of 0.1 mm, viewed using an eyepiece graticule. 0 10 20 30 40 50 60 70 80 90 100 Pollen grains were grown in a sugar solution and viewed using the eyepiece graticule. Diagram 1 shows the pollen grains at the start. Diagram 2 shows the pollen grains after 4 hours. diagram 1 diagram 2 pollen tube 0 10 20 30 40 50 60 70 80 90 100 0 10 20 30 40 50 60 70 80 90 100 at start after 4 hours What is the growth rate of the pollen tubes? A 5 μm h–1 B 10 μm h–1 C 5 mm h–1 D 10 mm h–1

Question

What are found in chloroplasts and also in mitochondria? 1 DNA 2 70S ribosomes 3 mRNA A 1, 2 and 3 B 1 and 2 only C 1 only D 2 and 3 only

Question

A long-distance runner has become adapted to run faster for longer after regular training. Which cell structure in a muscle cell has increased in number to allow this adaptation? A lysosome B mitochondrion C nucleus D smooth endoplasmic reticulum

Question

Some functions carried out within eukaryotic cells are listed. 1 lysosome production 2 polypeptide modification 3 exocytosis Which functions are carried out by the Golgi body? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

The diagram shows the structure of a unicellular organism. nucleus mitochondria cell membrane vacuole cytoplasm Which statement is correct for this organism? A It contains a nucleus so it is not prokaryotic. B It contains mitochondria so it is not a plant. C It does not have a cell wall so it must be eukaryotic. D It is unicellular so it must be a bacterium.

Question

Diastase is an enzyme that breaks down starch into maltose. A sample of starch is treated with boiled diastase and left for 15 minutes. Samples of the mixture are then tested with iodine solution and with Benedict’s solution. What is the correct result? iodine solution Benedict’s solution A blue-black blue B blue-black red C brown blue D brown red

Question

Which molecule is required for this reaction to occur? C12H22O11 + H2O → C6H12O6 + C6H12O6 A catalase B copper sulfate C hydrochloric acid D sodium hydroxide

Question

Which molecules contain at least two double bonds? unsaturated fatty acid C A D collagen haemoglobin B

Question

Which description of globular proteins is correct? A They are only found in cell surface membranes. B They only contain amino acids with hydrophilic R groups. C They can change shape by using energy from ATP. D They always have a quaternary structure of at least three polypeptides.

Question

Which diagram shows where a hydrogen bond occurs between two water molecules? A B δ– δ– O O δ+ δ+ δ+ δ+ H H H H δ– δ+ δ+ O H H δ+ δ+ H H O δ– key C D hydrogen bond δ+ δ+ O O δ– δ– δ– δ– H H H H δ– δ– δ+ H H O δ– δ– O H H δ+

Question

Some detergents disrupt hydrogen bonds between water molecules. Which row shows the correct effects of detergent on the specific heat capacity and latent heat of vaporisation of water? specific heat latent heat of capacity vaporisation A decreases decreases B decreases increases C increases decreases D increases increases

Question

An investigation was carried out to see if compound X could improve the thermostability of an enzyme. Thermostable enzymes will function well at high temperatures. The results of the investigation are shown. 120 100 80 enzyme experiment 2 activity 60 experiment 1 without compound X /% with compound X 40 20 0 10 20 30 40 50 60 70 temperature / °C Which row is correct? at 40 °C in experiment 1 at 45 °C in experiment 2 compound X makes the most of the enzyme approximately half of the enzyme more active sites will no longer enzymes are forming thermostable be complementary to the enzyme–substrate substrate complexes A B C D key = correct = not correct

Question

The table shows the results from an investigation into the effect of temperature on an enzyme-catalysed reaction. All other variables were standardised. rate of reaction temperature / °C / arbitrary units 10 3 20 7 30 16 40 33 50 32 60 14 What is the correct conclusion? A 40 °C was the optimum temperature. B The data for 50 °C was anomalous. C The optimum temperature was between 30 °C and 50 °C. D All the enzymes denatured at 60 °C.

Question

The graph shows how the rate of a reaction changes with substrate concentration in the presence of: no inhibitor inhibitor X inhibitor Y. One of the inhibitors is competitive and the other inhibitor is non-competitive. 0.006 0.005 no enzyme inhibitor 0.004 with inhibitor X rate of reaction 0.003 / mol dm–3 s–1 0.002 with inhibitor Y 0.001 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 substrate concentration / mol dm–3 What is the correct estimate of Km for the reaction shown when a competitive inhibitor is present? A 0.11 mol dm–3 B 0.23 mol dm–3 C 0.38 mol dm–3 D 0.65 mol dm–3

Question

Which of these substances can pass directly through cell surface membranes without using a carrier protein or channel protein? 1 K+ and Cl – 2 CO2 3 C6H12O6 A 1 and 2 B 1 and 3 C 2 and 3 D 2 only

Question

Which of these statements about facilitated diffusion are correct? 1 It is limited by the number of transport proteins. 2 It transports molecules against their concentration gradient. 3 It requires a source of ATP. A 1, 2 and 3 B 1 and 3 only C 1 only D 2 and 3 only

Question

A cell absorbs amino acids. This cell then synthesises and exports a digestive enzyme. Different cell structures are involved with different stages of this process. Which row shows a possible sequence of cell structures that the amino acids pass through? rough cell surface secretory Golgi body endoplasmic membrane vesicle reticulum A 1st 2nd 3rd 4th B 1st 3rd 4th 2nd C 4th 2nd 1st 3rd D 4th 1st 2nd 3rd

Question

The diagram shows apparatus set up to investigate the effect of changing the initial concentration of glucose in the surrounding solution on the movement of molecules through a selectively permeable membrane (Visking tubing) in 15 minutes. Visking tubing surrounding solution (different concentrations 10% glucose from 1% to 10% solution glucose solution) Which statements are correct as the initial concentration of glucose solution in the surrounding solution increases? 1 Net diffusion of water increases. 2 Glucose molecules reach an equilibrium quicker. 3 There is less change in the volume of the surrounding solution. 4 Net diffusion of glucose increases. A 1, 2, 3 and 4 B 1, 2 and 4 only C 1 and 3 only D 2 and 3 only

Question

The epithelium that lines the stomach is damaged by acid and is renewed every two days. Why is mitosis required to repair the damage? A Mitosis repairs damaged cells. B Mitosis produces new genetically similar cells. C Mitosis provides genetically identical replacement cells. D Mitosis doubles the original cell number.

Question

What is the role of telomeres? A allowing the chromatids to reach the poles during mitosis B holding sister chromatids together C making sure that the sister chromatids are of identical length D preventing loss of genes during DNA replication

Question

Which features of mitosis help to maintain the genetic composition of the cell? 1 the longitudinal division of the centromeres 2 the DNA of the parent cells replicates before mitosis begins 3 the pulling apart of the chromatids to opposite poles A 1, 2 and 3 B 1 and 3 only C 1 only D 2 and 3 only

Question

DNA forms a leading strand and a lagging strand during semi-conservative replication. Which row correctly matches the strands to their properties? the strand that is replicated by joining the strand that together short requires DNA ligase sequences of DNA in a 3′ to 5′ direction A lagging lagging B lagging leading C leading leading D leading lagging

Question

How many genes could code for one collagen molecule? A 1 gene only B 2 genes only C 3 genes only D 1 gene or 2 genes or 3 genes

Question

The diagram shows some events during the formation of an mRNA molecule at transcription. P 5′ 3′ Q Q S R What is correctly identified in the diagram? A P are introns. B Q are exons. C R is a primary transcript. D S are non-coding sequences.

Question

Two plants, K and L, are parasites of other plants. Both species grow structures that invade the vascular tissue of plants. Plant K grows into xylem tissue of other plants. Plant L grows into phloem tissue of other plants. Which substances could plants K and L take from the plants that they parasitise? plant K plant L A water only water and sucrose only B water and minerals water, amino acids and sucrose C water only amino acids and sucrose only D water and minerals water and sucrose only

Question

Which statements are correct for the apoplast pathway? 1 Water enters the cell wall. 2 Water moves by osmosis. 3 Water moves from cell wall to cell wall. 4 Water moves through plasmodesmata. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Question

Mass flow is the bulk movement of materials from one place to another. Which vessels carry fluids by mass flow? 1 artery 2 phloem sieve tube element 3 vein 4 xylem vessel element A 1, 2, 3 and 4 B 1, 2 and 3 only C 1 and 3 only D 2 and 4 only

Question

Which features are present in companion cells and also in phloem sieve tube elements? ribosomes plasmodesmata A key B = present C = not present D

Question

Which two terms describe the mammalian circulatory system? A open and double circulation B closed and double circulation C closed and single circulation D open and single circulation

Question

One function of an arteriole is to increase or decrease the flow of blood to tissues. Which of these must be present in an arteriole wall to allow this function? 1 collagen 2 endothelium 3 smooth muscle A 1, 2 and 3 B 1 and 3 only C 2 only D 3 only

Question

The table shows the blood pressures in different parts of the circulatory system of a person sitting at rest. parts of the blood pressure circulatory system / kPa aorta 16.0 arteriole 11.3 arterial end of capillary 4.7 venous end of capillary 1.3 vein 0.6 What is the percentage decrease in blood pressure between the arteriole and the arterial end of a capillary? A 42% B 58% C 142% D 240%

Question

Which reaction is catalysed by carbonic anhydrase? A the dissociation of carbonic acid B the formation of carbaminohaemoglobin C the formation of hydrogencarbonate ions and hydrogen ions D the association of carbon dioxide and water

Question

What directly causes the percentage oxygen saturation of haemoglobin to decrease in actively respiring muscles? A hydrogencarbonate ions B carbon dioxide C carbonic acid D hydrogen ions

Question

Which row shows the tissues that are present in the wall of the trachea and also the wall of the bronchus? ciliated squamous smooth epithelium epithelium muscle A key B = present in trachea and bronchus C = not present in trachea or bronchus D

Question

Outbreaks of cholera commonly occur in camps that are set up after a major natural disaster. The list shows some control measures that can be taken to limit the spread of cholera in the camps. 1 treating all drinking water supplies with a high concentration of chlorine 2 setting up an emergency treatment centre to isolate cases of cholera and treat them with antibiotics 3 using concentrated disinfectant to clean sewage disposal areas and infected bedding 4 health workers visiting regularly to detect cases 5 keeping good records of the number of cases and deaths at treatment centres Which features of these control measures involve an economic factor? A 1, 2, 3, 4 and 5 B 1, 3 and 5 only C 2, 3, 4 and 5 only D 2 and 4 only

Question

Antibiotics are used to treat many infections. Each antibiotic has one or more biochemical targets. Tetracycline inhibits 70S ribosomes. Rifamycin inhibits prokaryotic RNA polymerase. Which antibiotics can be used to treat an infection caused by the influenza virus? penicillin tetracycline rifamycin A key B = can be used C = cannot be used D

Question

Which cells involved in the primary immune response are phagocytes? A monocytes B plasma cells C T-helper cells D T-killer cells

Question

Some ways in which different types of monoclonal antibodies can work are described. 1 binding to proteins on cell surfaces and triggering the immune system 2 blocking molecules on cell surfaces that inhibit T-cells 3 blocking cell signalling receptors that trigger cell division 4 blocking cell signalling receptors that trigger the immune response Which types of monoclonal antibody could be used to treat cancer? A 1, 2, 3 and 4 B 1, 2 and 3 only C 1 and 4 only D 2, 3 and 4 only