2026 TJC JC2 Prelim H2 Biology P2 (QP)

1 [TURN OVER READ THESE INSTRUCTIONS FIRST Write your Center number, index number and name in the spaces at the top of this page. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, 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 any working or if you do not use appropriate units. TEMASEK JUNIOR COLLEGE 2026 JC2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME CENTRE NUMBER S INDEX NUMBER BIOLOGY 9477/02 Paper 2 Structured Questions 28 AUGUST 2026 2 hours Candidates answer on the Question Paper. No Additional Materials are required. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use 1 / 10 2 / 10 3 / 8 4 / 8 5 / 7 6 / 15 7 / 10 8 / 8 9 / 8 10 / 6 Total / 90 This document consists of 28 printed pages and 1 blank page.

2 Answer all questions. 1 A plasma B lymphocyte is involved in the adaptive immune response. In an investigation, plasma B lymphocyte were grown in a culture medium containing fluorescent - tagged amino acids. Samples of these cells were taken and the level of fluorescence in three organelles was measured. Table 1.1 shows the results of this investigation. Table 1.1 time after fluorescent-tagged amino acids were added to the culture medium / min level of fluorescence present / arbitrary units (a.u.) organelle A organelle B organelle C 1 21 120 6 20 52 88 6 40 86 39 8 60 71 23 15 90 50 27 28 120 23 11 51 (a) Suggest a reason for using amino acids that were fluorescent-tagged. …………………….………………………………………………………………………………………… .……………….…..……………………………………………………………………………………… [1] (b) State and explain how amino acids enter the cell. …………….….…………………………………………………………………………………………….. …………….….…………………………………………………………………………………………….. …………….….…………………………………………………………………………………………….. …………………….………………………………………………………………………………………… .……………….…..……………………………………………………………………………………… [2]

3 [TURN OVER (c) With reference to Table 1.1, (i) identify organelle A and B; A ……………………………………………………………………………………………………… B ……………………………………………………………………………………………………… [2] (ii) explain the changes in the level of fluorescence in organelle B. ……………………..…………………….…………………………………………………………… ……………………..…………………….…………………………………………………………… ……………………..…………………….…………………………………………………………… ……………………..…………………….…………………………………………………………… …………………………….……………….…..……………….………………………………… [2] (d) Describe how the Golgi apparatus functions in the synthesis of glycoproteins such as antibodies. …………….….………………………………………………………………………………………….….. …………….….……………………………………………………………………………………….…….. …………….….……………………………………………………………………………………….…….. …………………….………………………………………………………………………………………… .……………….…..……………………………………………………………………………………… [2] (e) Name the organelle where class switching occurs in the plasma B lymphocyte. …………….….……………………………………………………………………………………..…… [1] [Total: 10]

4 2 Osteogenesis imperfecta (OI) is a genetic disorder of connective tissues caused by an abnormality in the synthesis or processing of type I collagen, a protein crucial for bone strength. It is also called brittle bone disease. It is characterised by an increased susceptibility to bone fractures. While primarily affecting bones, OI can impact other connective tissues like skin and ligaments. Fig 2.1 below shows amino acids that are found in collagen. Fig 2.1 (a) Select two amino acids from Fig. 2.1 that are most commonly present in collagen. Draw in the space below to show they are joined during the synthesis of collagen. [3] arginine glycine proline serine

5 [TURN OVER (b) Explain in the terms of the property of the amino acid R groups, why a substitution mutation of glycine to arginine results in a more severe case of brittle bones than substitution with serine. …………….….……………………………………………………………………………………………... …………….….………………………………………………………………………………………….….. …………….….………………………………………………………………………………………….….. …………….….……………………………………………………………………………………….…….. …………….….……………………………………………………………………………………….…….. …………………….………………………………………………………………………………………… .……………….…..……………………………………………………………………………………… [3] (c) Individuals with OI often suffer from ana emia, a disease which is linked to haemoglobin, an important protein found in red blood cells. (i) Table 2.1 lists two proteins found in cells. Complete Table 2.1 by placing a tick () to show whether the feature is present in collagen and / or haemoglobin or a cross (✘) if the feature is absent. Put a tick () or a cross (✘) in every box. Table 2.1 feature collagen haemoglobin globular shape metal ion covalent cross-links [3] (ii) Suggest why individuals with OI tend to suffer from anaemia. ……………………..…………………….…………………………………………………………… …………………………….……………….…..……………….………………………….……… [1] [Total: 10]

6 3 Lysosomes are membrane-bound organelles. (a) Scientists measured the concentration of cholesterol in the membrane of lysosomes in a mammalian cell. The concentration of cholesterol in the lysosome membrane was found to be lower than the concentration in other membranes inside mammalian cells. (i) State how a lower concentration of cholesterol would make the properties of lysosome membranes different from other membranes in mammalian cells. …………………………….……………….…..……………….…………………………….…… [1] (ii) Suggest why the lower concentration of cholesterol in lysosome membranes would help lysosomes carry out their function. ……………………..…………………….…………………………………………………………… …………………………….……………….…..……………….…………………………………. [1] The enzyme α-galactosidase is present in lysosomes. Students investigated the effect of substrate concentration on the rate of reaction catalysed by α-galactosidase at pH 4.5 and at pH 5.9 The results are shown in Fig 3.1. Fig 3.1 Fig. 3.1 (b) Using the data in Fig. 3.1, determine the Michaelis -Menten constant, Km, for α-galactosidase at pH 4.5. State your answer in the appropriate units. Km …………………………….… [1] rate of reaction / pmol min-1 substrate concentration / µmol dm-3 pH 5.9 pH 4.5

7 [TURN OVER (c) With reference to Fig 3.1, (i) describe the differences in the results at pH 4.5 and pH 5.9; ……………………..…………………….…………………………………………………………… ……………………..…………………….…………………………………………………………… ……………………..…………………….…………………………………………………………… ……………………..…………………….…………………………………………………………… …………………………….……………….…..……………….……………………………….… [2] (ii) suggest explanations for the differences. ……………………..…………………….…………………………………………………………… ……………………..…………………….…………………………………………………………… ……………………..…………………….…………………………………………………………… ……………………..…………………….…………………………………………………………… ……………………..…………………….…………………………………………………………… ……………………..…………………….…………………………………………………………… …………………………….……………….…..……………….…………………………….…… [3] [Total: 8]

8 4 Mitochondria is a membrane-bound organelle and the outer membrane has porin which allows diffusion H+ into the intermembrane space. The chemiosmotic theory was first proposed by Peter Mitchell in 1961. It has since been confirmed by experiments using isolated mitochondria. One of the experiments was conducted as follows: • Mitochondria were isolated from liver cells. • The mitochondria were transferred to a buffer solution. • The solution was poured into glass dishes, labelled A to D, to which ADP, Pi (inorganic phosphate)