2025 CJC H2Bio PE P2 (Ans)

NAME: ___________________________________________ CLASS: _________ INDEX: __________ CATHOLIC JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION Higher 2 BIOLOGY 9744/02 STRUCTURED QUESTIONS 01 Sept 2025 2 hours READ THESE INSTRUCTIONS FIRST Write your name (as per NRIC), class, and index number on all the work you hand in. Write in dark blue or black pen on both sides of the paper. [PILOT FRIXION ERASABLE PENS ARE NOT ALLOWED] You may use a soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. The number of marks is given in brackets [ ] at the end of each question or part question. There are 11 questions with multiple subparts in this paper. Answer all questions in the spaces provided on the Question Paper. This document consists of 39 printed pages and 0 blank pages. [Turn over] For Examiner’s Use Total 100 1 2 3 4 5 6 7 8 9 10 11 Suggested Answers

2 2025 Prelim/ 9744/ 02 Answer all questions 1 Fig. 1.1 shows ribosomes attached to the endoplasmic reticulum, carrying out protein synthesis. Fig. 1.1 (a) Name the structures labelled A to C ….……………………………………………………………………………………………………………...... ……..…………………………………………………………………………………………………………. [3] A – mature mRNA B – Growing polypeptide C – Lumen of the RER/Cisterna (b) With reference to Fig. 1.1, suggest the function of the protein that forms the membrane channel. ….……………………………………………………………………………………………………………...... ….……………………………………………………………………………………………………………...... ….……………………………………………………………………………………………………………...... ….……………………………………………………………………………………………………………...... ….……………………………………………………………………………………………………………...... ……..…………………………………………………………………………………………………………. [3]

3 2025 Prelim/ 9744/ 02 1. The function of the protein that forms the membrane channel is to allow large and polar molecules, such as polypeptide, to be transported across the membrane. 2. The protein also functions as a receptor to allow the binding of the signal peptide from the initial translation of the mRNA. 3. This allows the ribosome to bind to/dock and anchor onto the endoplasmic reticulum to complete the translation of protein directly into the cisternae of the ER. (c) Proteins synthesised by ribosomes attached to the endoplasmic reticulum may be transported out of the cell. Explain the type of modification that occurs and the route taken. ….……………………………………………………………………………………………………………...... ….……………………………………………………