NYJC 2023 H2 Biology 9744 P2 QP

9744 / H2 Biology / 02 NANYANG JUNIOR COLLEGE JC 2 Preliminary Examination Higher 2 CANDIDATE NAME CLASS BIOLOGY 9744/02 Paper 2 Structured Questions 14 September 2023 Candidates answer on the Question Paper. No Additional Materials are required. 2 hours READ THESE INSTRUCTIONS FIRST Write your name and CT on all the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, highlighters, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions in the spaces provided on the Question Paper The use of an approved scientific calculator is expected, where appropriate. You may lose marks if you do not show your working or if you do no use appropriate units. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use 1 2 3 4 5 6 7 8 9 10 Total This document consists of 24 printed pages. [Turn over

9744 / H2 Biology / 02 2 Answer all the questions. 1 Polysaccharides, such as glycogen, are composed of thousands of monomers. Oligosaccharides are carbohydrates that contain three to ten monomers in their chain. Nystose is one example of an oligosaccharide. The structure of nystose is shown in Fig. 1.1. Fig 1.1 (a) State three differences between the structures of nystose and glycogen, other than the number of monomers in the molecules. 1 2 3 [3] (b) One of the enzymes involved in glycogen synthesis is glycogen synthase. The monomer of the glycogen polymer is α-glucose. (i) Draw the ring form of α-glucose in the space provided. (ii) [2]

9744 / H2 Biology / 02 3 (iii) The gene coding for glycogen synthase is known as GYS1 . Glycogen synthase catalyses the formation of a covalent bond between two α-glucose molecules during glycogen synthesis. Name the type of bond formed. [1] (iv) Glycogen branching enzyme is another enzyme that is required for glycogen synthesis. Suggest why glycogen branching enzyme is needed in addition to glycogen synthase. [1] (c) Table 1.1 shows three functions of cell structures that are involved in the synthesis of glycogen synthase. Complete Table 1.1 by naming the cell structure that carries out the function listed. Table 1.1 function name of cell structure assembles ribosomes for polypeptide synthesis synthesizes ATP to provide a supply of energy for the transcription of GYS1 folds and modifies synthesized polypeptide to produce functioning glycogen synthase [3] [Total: 10]

9744 / H2 Biology / 02 4 2 There are a number of mutations affecting the production of fetal haemoglobin, HbF, and normal adult haemoglobin, HbA. • The HbA allele codes for the normal β-globi