HCI H2 Bio 2024 Prelim P2 Qn

© Hwa Chong Institution 2024 9744 H2 Biology / JC2 Preliminary Examinations / Paper 2 HWA CHONG INSTITUTION JC2 Preliminary Examinations Higher 2 CANDIDATE NAME CT GROUP 23S7__ CENTRE NUMBER INDEX NUMBER BIOLOGY Paper 2 Structured Questions Candidates answer on the Question Paper. No Additional Materials are required. 9744/02 22 August 2024 2 hours INSTRUCTIONS TO CANDIDATES There are six question booklets (I - VI) to this paper. Write your name, CT group, Centre number and index number in the spaces provided at the top of this cover page and on the lines provided at the top of the cover pages of Booklets II, III, IV, V and VI. There are eleven questions. Answer all questions in the spaces provided on the Question Paper. INFORMATION FOR CANDIDATES 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 not use appropriate units. The number of marks is given in brackets [ ] at the end of each question or part question. You are reminded of the need for good English and clear presentation in your answers. This document consists of 25 printed pages. For Examiners' Use 1 / 9 2 / 8 3 / 10 4 / 10 5 / 10 6 / 10 7 / 13 8 / 10 9 / 10 10 / 5 11 / 5 Total / 100

2 © Hwa Chong Institution 2024 9744 H2 Biology / JC2 Preliminary Examinations / Paper 2 QUESTION 1 Fig 1.1 shows the amoeba, a unicellular organism that inhabit s freshwater ponds. It exhibits characteristic motility. Fig. 1.1 (a) Describe one feature visible in Fig. 1.1 that identifies the amoeba as a eukaryotic organism. [1] The amoeba contains structures called contractile vacuoles. They expel excess water from the cell. A contractile vacuole first increases in size, then migrates to and fuses with the cell surface membrane. Proteins, synthesised using the endomembrane system, are embedded within the membrane of these contractile vacuoles where they pump ions into the lumen of the contractile vacuoles. (b)(i) Explain how the structure of the contractile vacuole membrane enables it to perform its function. [4]

3 © Hwa Chong Institution 2024 9744 H2 Biology / JC2 Preliminary Examinations / Paper 2 (c)(ii) Explain how organelles of the endomembrane system are involved in the synthesis of proteins embedded within the membranes of contractile vacuoles. [4] [Total: 9]

4 © Hwa Chong Institution 2024 9744 H2 Biology / JC2 Preliminary Examinations / Paper 2 QUESTION 2 Keratin is the structural protein in the feathers of birds. Keratin polypeptides are composed of a high proportion of cysteine amino acids, which have sulfur-containing R groups. Keratin polypeptides form filaments. The two main types of keratin in f