2026 DHS H2 Biology Prelim Paper 1 (with answers)

© DHS 2026 9477/01 [Turn over Name: Centre/Index Number: Class: DUNMAN HIGH SCHOOL Preliminary Examination Year 6 H2 BIOLOGY Paper 1 Multiple Choice You must answer on the multiple choice answer sheet. You will need: Multiple choice answer sheet Soft clean eraser Soft pencil (type B or HB is recommended) 9477/01 22 September 2026 1 hour INSTRUCTIONS ● There are thirty questions on this apper. Answer all questions. ● For each question there are four possible answers A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the multiple choice answer sheet. ● Write in soft pencil. ● Write your name, centre number and index number on the multiple choice answer sheet in the spaces provided unless this has been done for you. ● Do not use correction fluid or tape. ● Do not write on any bar codes. ● You may use an approved calculator. INFORMATION ● The total mark for this paper is 30. ● Each correct answer will score one mark. ● Any rough working should be done on this question paper. This document has 28 pages. Any blank pages are indicated.

2 © DHS 2026 9477/01 1 Which observation does not support the cell theory? A Plant cells placed in a hypotonic solution grow rapidly in size. B Glucose molecules that enter a cell are quickly oxidised to pyruvate molecules. C One cancer cell rapidly forms a cluster of cells. D The amount of nuclear DNA in a cell doubles during S phase of the cell cycle. 2 Which row shows features that occur in plant cells and bacterial cells? 70S ribosomes 80S ribosomes centrioles circular DNA A ✓ ✗ ✓ ✗ B ✓ ✗ ✗ ✓ C ✗ ✓ ✓ ✗ D ✗ ✓ ✗ ✓ 3 Which statement describes how the molecular structure of starch is suited to its function? A Amylose has a branched structure and amylopectin is coiled to give a compact molecule for transport. B In the breakdown of amylose and amylopectin, many condensation reactions release stored energy. C In the formation of amylose and amylopectin, many hydrolysis reactions allow the release of stored energy. D Amylose and amylopectin form a complex that is insoluble and so does not affect the water potential of the cell.

3 © DHS 2026 9477/01 [Turn over 4 Raffinose is a trisaccharide which can be degraded by enzymes. The results of two different enzymatic incubations are shown: enzyme used products sucrase melibiose and fructose galactosidase galactose and sucrose Which statements are consistent with the results shown above? 1 Raffinose is composed of two different monosaccharides. 2 Melibiose is a disaccharide. 3 Acid hydrolysis of raffinose will yield glucose. 4 The products of raffinose digestion by sucrase and galactosidase will each yield an orange-red precipitate when heated with Benedict's reagent. A 1, 2, 3 and 4 B 2, 3 and 4 only C 1 and 3 only D 2 and 4 only

4 © DHS 2026 9477/01 5 Phosphatidylcholines make up a large proportion of phospholipids in cell membranes. They are phospholipids that have choline as part of their polar head section, as shown in the diagram below. Four different phospholipases, A 1, A 2, C and D, act on different parts of the phosphatidylcholine molecule as indicated. It is known that in phosphatidylcholines: • saturated fatty acids are more commonly found in position R 1 than unsaturated fatty acids, and • unsaturated fatty acids are more commonly found in position R 2 than saturated fatty acids. The table shows the four most abundant fatty acids that form part of phosphatidylcholines. fatty acid molecular formulae palmitic acid C16H32O2 CH3(CH2)14COOH linoleic acid C18H32O2 CH3(CH2)4(CH=CHCH2)2(CH2)6COOH oleic acid C18H34O2 CH3(CH2)7CH=CH(CH2)7COOH steric acid C18H36O2 CH3(CH2)16COOH Which statement about phospholipase action on isolated phosphatidylcholines is correct? A The action of phospholipase A 1 is likely to yield a higher proportion of oleic acid than stearic acid. B The action of phospholipases A1 and A2 will cause an increase in the pH of the reaction medium. C The action of phospholipase A2 is likely to yield a higher proportion of linoleic acid than palmitic acid. D The products of the combined action of phospholipases A1, A2, C and D will be free fatty acids, glycerol and choline only.

5 © DHS 2026 9477/01 [Turn over 6 Which row best describes the different levels of protein structure? primary structure secondary structure quaternary structure A is the number of amino acids present in a protein. is the left-handed spiral formed by the primary structure. is the sub-unit polypeptides that link together to form a protein. B is the order of amino acids present in a protein encoded by DNA. is the coiling of a chain of amino acids to form a β- pleated sheet or α-helix. contains two types of polypeptide that interact forming the shape of a protein. C is the result of translation of an mRNA molecule by a ribosome into a chain of amino acids. occurs because of attraction between hydrogen and oxygen atoms in the peptide bonds. is formed by four polypeptides and an additional reactive group attached to the protein. D is the sequence of amino acids in a protein coded by an mRNA molecule. is formed by hydrogen bonding between amino acids forming the primary structure. is formed by the linking together of more than one polypeptide to form a protein.

6 © DHS 2026 9477/01 7 The diagram shows the constituent biomolecules in a cell membrane. Which row identifies the functions of two of the labelled molecules? molecule function molecule function A 1 allows tissue formation 4 regulates the fluidity of the membrane B 2 acts as a receptor 5 active transport C 3 facilitates diffusion 4 regulates the fluidity of the membrane D 6 bulk transport 5 acts as an enzyme

7 © DHS 2026 9477/01 [Turn over 8 The diagram shows a metabolic pathway involved in the production of lysine in a bacterial cell. Which change in enzyme activity will result in the greatest increase in lysine yield? enzyme change in activity A 1 decrease B 2 increase C 3 increase D 4 decrease

8 © DHS 2026 9477/01 9 A double-stranded DNA is being replicated in a cell. The diagram shows a section of a DNA template with its associated lagging strand. The stage shown is prior to the removal of the RNA primers. Which of the following correctly represents the events taking place during the synthesis of the lagging strand? method of synthesis first Okazaki fragment synthesised location of bond catalysed by DNA ligase after removal of RNA primer A discontinuous O3 L1 B discontinuous O3 L2 C continuous O1 L1 D continuous O1 L2

9 © DHS 2026 9477/01 [Turn over 10 Which row describes an advantage and limitation of the polymerase chain reaction? advantage limitation A only requires a minute amount of template for amplification only able to amplify a small fragment of DNA B able to produce 202 copies of the target DNA after 20 cycles cannot amplify unknown sequences as primers cannot be made C works on DNA from various species and sources time consuming and expensive to carry out D highly accurate due to proof-reading function of DNA polymerase extent of amplification is limited by the amounts of nucleotides and primers 11 One complete turn of the double helix of DNA contains 10 pairs of bases and is 3.4 nm long. What is the approximate length of the DNA coding sequence of lysozyme, a protein of 129 amino acids? A 132 nm B 113 nm C 66 nm