ASRJC 2023 JC2 H2 Biology Prelims Paper 2 (Ans)

ASRJC BIOLOGY DEPT 9744/2023/J2PRELIM/P2 [Turn over H2 ANDERSON SERANGOON JUNIOR COLLEGE HIGHER 2 ANSWERS 2023 JC2 PRELIMINARY EXAMINATIONS CANDIDATE NAME CLASS INDEX NUMBER BIOLOGY 9744/02 PAPER 2 SHORT STRUCTURED QUESTIONS Candidates answer on the Question Paper. No Additional Materials are required. 13 SEPTEMBER 2023 WEDNESDAY 2 HOURS READ THESE INSTRUCTIONS FIRST Write your name and class on all the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graph Do not use paper clips, highlighters, glue or correction fluid. Answer all questions. 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. 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. This document consists of 25 printed pages and 7 blank page For Examiner’s Use 1 2 3 4 5 6 7 8 9 10 11 Total /100

ASRJC BIOLOGY DEPT 9744/2023/J2PRELIM/P2 Answer all the questions. 1 Archaea are single-celled microorganisms which inhabit extreme environments, such as hot springs and volcanic vents at temperatures over 100C. Fig. 1.1 shows the molecular structure of a phospholipid found in the cell membrane of an archaea and that of a eukaryote. Fig. 1.1 (a) (i) With reference to Fig. 1.1, state two structural differences between the two phospholipids. [2] [Any one] 1. The fatty acid tails/ hydrocarbon chains of archaeal phospholipid are both saturated/ only contain C-C single bonds , but the fatty acid tails/ chains of eukaryote phospholipid consist of a saturated and an unsaturated chain/ contain a C=C double bond. 2. The fatty acid tails/ hydrocarbon chains of archaeal phospholipid are longer/ contained more C and H , but the fatty acid tails/ chains of eukaryote phospholipid are shorter/ contain fewer C and H. 3. Side chains are present in the fatty acid tails/ hydrocarbon chains of archaeal phospholipid, but these are absent in the fatty acid tails/ chains of eukaryote phospholipid.

3 ASRJC BIOLOGY DEPT 9744//2023/PRELIM/P2 [Turn over (ii) Explain why phospholipids are unable to provide structural support. [3]  Phospholipids is not a long, linear, macromolecule joined by strong covalent bonds wh