Biology 9700/11 October/November 2025: question paper and mark scheme

Question

In a photomicrograph of magnification ×5000, a chloroplast measures 25 mm in diameter. What is the actual diameter of the chloroplast? A 0.2 μm B 0.5 μm C 2 μm D 5 μm

Question

What is a function of Golgi bodies? A formation of vesicles for endocytosis B modification of proteins for secretion C synthesis of ATP D synthesis of polypeptides

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A cell in the human body is specialised for synthesis and secretion of lipids. Which row shows the organelles required by the cell for synthesis and secretion of lipids? smooth mitochondria endoplasmic vesicles reticulum A key B = required C = not required D

Question

The photomicrograph shows part of a cell. Which row is correct? the organelles this cell will this could be shown could be contain 70S part of a used to make ribosomes plant cell antibodies A key B = correct C = not correct D

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Which statement about viruses is correct? A They are cells with a capsid made of phospholipids. B They are cells with a capsid made of protein. C They are particles with a capsid made of phospholipids. D They are particles with a capsid made of protein.

Question

Solution X was tested for the presence of non-reducing sugars. It did not contain reducing sugars. Some steps that can be used to test for the presence of biological molecules are listed. 1 Add Benedict’s solution to the test-tube. 2 Add dilute hydrochloric acid to the test-tube. 3 Add sodium hydrogencarbonate to the test-tube. 4 Heat the test-tube in a water-bath. Which order of steps to identify the presence of non-reducing sugars in solution X is correct? A 1→4 B 2→3→1→4 C 2→4→3→1→4 D 3→2→4→1

Question

The diagram shows the structure of part of a biological molecule. HOH2C O O CH2 O HO CH2OH OH OH OH OH HOH2C O O HO CH2 OH HOH2C O O CH2 O O CH2 O O HO HO HO CH2OH CH2OH CH2 OH OH OH HOH2C O O HO CH2 OH HOH2C O O HO CH2 OH Which statements about this biological molecule are correct? 1 It has monomers joined by ester bonds. 2 It is a macromolecule. 3 It is a polysaccharide. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

Which diagram has a covalent bond that joins monomers together to form a biological polymer in eukaryotes? A B C D O R H O R O R R NH3+ – O C R C O R O R O P O R O–

Question

Which feature of storage polysaccharides means they do not change the water potential of cells? A They are easily hydrolysed. B They are compact. C They are insoluble. D They are branched molecules.

Question

Which molecules contain at least four double bonds? saturated triglyceride C A D collagen haemoglobin B

Question

In some people a mutation can affect the beta chains in their haemoglobin molecules. As a result polar amino acids on the outer surfaces of the chains are replaced by non-polar amino acids. What will be the effect on haemoglobin? A Haemoglobin will become less soluble. B Haemoglobin will become more soluble. C Hydrophobic interactions between amino acids will decrease. D More hydrogen bonds will form in the molecule.

Question

The graph shows the effect of substrate concentration on an enzyme-catalysed reaction with and without a competitive inhibitor. rate of key reaction with inhibitor without inhibitor substrate concentration What is the effect of the competitive inhibitor on Vmax and Km? A Vmax decreases and Km decreases. B Vmax stays the same and Km decreases. C Vmax stays the same and Km increases. D Vmax decreases and Km stays the same.

Question

The graph shows energy changes in a chemical reaction. 1 2 4 energy 3 progress of reaction What is the activation energy when an enzyme is added? A 1+2 B 2 only C 3–2 D 4

Question

The diagram shows an enzyme, its substrate and an enzyme–substrate complex. enzyme substrate enzyme–substrate complex Which statement explains how this substrate is able to enter the active site of this enzyme? A Contact between the substrate and the enzyme causes a change in the enzyme shape. B The shape of the active site and the shape of the substrate are complementary. C The substrate within the active site forms hydrogen bonds with amino acids. D When the enzyme–substrate complex forms, the tertiary structure of the enzyme changes.

Question

What are the main roles of glycolipids in cell surface membranes? 1 to help cells to attach to each other to form tissues 2 to act as antigens for cell-to-cell recognition 3 to increase fluidity for the cell surface membrane A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

A sample of healthy plant cells taken from the same tissue is placed in a beaker containing distilled water. The cells change in size. What would explain this change in size? A Water will leave the cells by active transport. B Water will enter the cells by osmosis. C Solutes will enter the cells by active transport. D Solutes will leave the cells by osmosis.

Question

A student studying surface area to volume ratio and diffusion made a cuboid, S1, using agar stained blue with a pH indicator. The dimensions of S1 are shown in the diagram. The student made a second agar cuboid, S2. Each dimension of S2, (the length, the width and the height), was half that of S1. S1 S2 30 mm not to scale 15 mm 5 mm 2.5 mm 8 mm 4 mm The student placed each cuboid in a test-tube and covered it in acid. The time taken for each cuboid to completely change colour was recorded. All variables other than the size of the cuboids were standardised. Which row shows the surface area to volume ratio of S1 and the time taken for S1 to change colour completely in acid compared to the time taken for S2 to change colour completely? time taken for S1 to change surface area to colour completely in acid volume ratio of S1 compared to S2 A 0.72 : 1 S1 takes less time than S2 B 0.72 : 1 S1 takes more time than S2 C 1.4 : 1 S1 takes less time than S2 D 1.4 : 1 S1 takes more time than S2

Question

Two test-tubes, labelled X and Y, were set up containing equal volumes of solution X or solution Y respectively. A large number of type P cells and a large number of type Q cells were added into test-tube X and also into test-tube Y. After a few minutes, samples of the solutions were taken and the cells were observed with a microscope. ● In solution X, all of cell type P had burst and cell type Q had not burst. ● In solution Y, no cells had burst. Which row correctly identifies cell type Q and solutions X and Y? cell type Q solution X solution Y A red blood cells 5% NaCl solution distilled water B goblet cells 5% glucose solution distilled water C liver cells distilled water 5% glucose solution D root hair cells distilled water 5% NaCl solution

Question

A human muscle cell contains 46 chromosomes. How many centromeres will be present in a cell during the stages of the mitotic cell cycle? early prophase metaphase anaphase A 46 46 92 B 46 92 92 C 46 46 46 D 92 46 46

Question

Telomeres become shorter during each cell cycle of a specialised cell. In which phase of the cell cycle do telomeres shorten? A cytokinesis B G1 C S D G2

Question

The photomicrographs show stages of mitosis. 1 2 3 4 5 What is the correct order for the stages of mitosis? A 2→3→5→1→4 B 2→4→1→5→3 C 3→2→5→4→1 D 5→1→4→3→2

Question

The gene that codes for protein R is 130 kb long. Protein R is 220 kDa in mass. The typical mass of an amino acid is 110 Da. (1000 base pairs = 1 kb, 1000 Da = 1 kDa) Which row is correct? approximate length approximate length of introns in this of mRNA for this gene / base pairs gene / base pairs A 6000 6000 B 6000 130 000 C 124 000 6000 D 124 000 130 000

Question

The diagram shows a section of DNA. Two of the bases in this section are labelled 1 and 2. O 1 O O O O O 2 Which row correctly identifies the bases 1 and 2? base 1 base 2 A purine adenine B purine guanine C pyrimidine adenine D pyrimidine guanine

Question

Which row describes the role of the enzymes DNA polymerase and DNA ligase? DNA polymerase DNA ligase A adds nucleotides in joins sections of DNA together a 5′ to 3′ direction on the lagging strand B adds nucleotides in joins sections of DNA together a 3′ to 5′ direction on the leading strand C adds nucleotides in joins sections of DNA together a 3′ to 5′ direction on the lagging strand D adds nucleotides in joins sections of DNA together a 5′ to 3′ direction on the leading strand

Question

The table shows some of 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 template DNA 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 two different amino acids? A CCA ATC ACG GCG TTG GCA B CCA TTC ACA GCA TTA GCA C CCA TTC ACG CCG TTA GCC D CCA TTC ACG GCG TTC GGA

Question

The diagram shows a vertical section through part of the stem of a dicotyledonous plant. Three types of structures are labelled. U V W What are the structures U, V and W? companion phloem sieve xylem vessel cells tube elements elements A U W V B V U W C U V W D W V U

Question

Which features of xylem vessels help to reduce the resistance to water flow? 1 Lignin forms an incomplete secondary wall. 2 There are no cross walls between the vessel elements. 3 The xylem vessels form narrow tubes. A 1, 2 and 3 B 1 and 2 only C 2 only D 3 only

Question

What causes water to move from the root hair cells to the endodermis? A diffusion through cell walls and osmosis down a water potential gradient in the cytoplasm B diffusion through the symplast and osmosis and root pressure through the apoplast C osmosis from cell vacuole to cell vacuole and active transport into the endodermis D osmosis through the intercellular spaces and diffusion in cell walls and cytoplasm

Question

Which changes occur as carbohydrate is moved into a sink? water potential volume of liquid of the sieve tube of the sieve element becomes tube element A lower decreases B lower increases C higher decreases D higher increases

Question

Which statement correctly compares blood plasma and tissue fluid in a healthy person? A Blood plasma contains more protein than tissue fluid. B Both blood plasma and tissue fluid contain red blood cells. C Tissue fluid contains white blood cells whereas blood plasma does not contain lymphocytes. D Tissue fluid is formed from blood plasma and is not returned to blood plasma.

Question

The body maintains an average normal blood pH of 7.4. Which row describes the conditions that would increase the dissociation rate of haemoglobin the most during periods of intense exercise? blood CO2 partial blood pH pressure / kPa A 7.2 5.6 B 7.2 9.5 C 7.6 5.6 D 7.6 9.5

Question

The graph shows changes in blood pressure during one cardiac cycle. 16 14 12 10 blood key pressure 8 aorta / kPa ventricle 6 atrium 4 2 0 0 X 0.75 time / s What is happening at time X? aortic semilunar atrium valve A closing emptying B closing filling C opening emptying D opening filling

Question

How many times must a carbon dioxide molecule pass through a cell surface membrane to travel from the tissue fluid into the blood plasma? (Assume there are no pores between the cells the carbon dioxide molecule must pass through.) A 1 B 2 C 3 D 4

Question

Two types of epithelial cells, 1 and 2, occur in the mammalian gas exchange system in a healthy human. 1 2 Which row shows the function and distribution of these types of epithelial cells? cell type 1 cell type 2 A absorption in bronchi secrete mucus in alveoli B exchange surface in alveoli secrete mucus in bronchi C absorption in bronchi move mucus in alveoli D exchange surface in alveoli move mucus in bronchi

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Which tissues would be seen in a photomicrograph of the wall of the trachea? elastic fibres smooth muscle A key B = present C = not present D

Question

The graph shows the decrease in cases of tuberculosis (TB) in a country between 1910 and 2000. 90 000 80 000 70 000 60 000 number 50 000 of cases per year 40 000 30 000 20 000 10 000 0 1910 1920 1940 1960 1980 2000 year Which factors could have contributed to the fall over this period? 1 pasteurisation of milk 2 the provision of new housing to reduce overcrowding 3 removing large pools of stagnant water 4 identification of contacts of people infected with TB A 1, 2 and 4 B 1 and 3 C 1 and 4 only D 2, 3 and 4

Question

The pathogens for some diseases are transmitted by vectors. Which disease is transmitted with the help of a vector that could be controlled by the removal of pools of water? A cholera B HIV/AIDS C malaria D tuberculosis

Question

How does penicillin affect bacteria? A It inhibits DNA replication by binding to nucleotides. B It inhibits translation by preventing tRNA binding to ribosomes. C It is a competitive inhibitor of an enzyme in cell wall synthesis. D It is a competitive inhibitor of an enzyme in protein synthesis.

Question

The hybridoma method is used for the production of monoclonal antibodies. Which two types of cell are used in this method? A stem cell and B-lymphocyte B stem cell and T-lymphocyte C tumour cell and B-lymphocyte D tumour cell and T-lymphocyte

Question

What describes a non-specific immune response? A activation of killer T-lymphocytes by infected cells B cloning of B-lymphocytes to form plasma cells C ingestion of a bacterial cell by a neutrophil D recognition of antigens on the cell surface of macrophages