2024 JPJC Prelim 9744 Biology P2 (A)(1)

9744 / 02 [Turn over NAME : CLASS : JURONG PIONEER JUNIOR COLLEGE JC2 Preliminary Examination 2024 BIOLOGY Higher 2 9744/02 27 August 2024 Paper 2 Structured Questions 2 hours Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your class 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. 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 not use appropriate units. 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 11 Total This document consists of 19 printed pages and 1 blank page.

2 JPJC/JC2 H2 Biology/Prelim/2024 Section A Answer all questions 1 (a) Fig. 1.1 shows a single-celled organism called Chlamydomonas. Fig. 1.1 (i) Name two structures that could be present inside the nucleus. [2] 1. nucleolus ; 2. DNA / rRNA / mRNA / chromatin / nucleosome / histones / ribosomal subunits (ii) Chlamydomonas lives in freshwater ponds. It uses its flagella to swim towards light of moderate intensity but away from very bright light. Using information in Fig. 1.1, explain the advantage of this behaviour. [2] 1. (compulsory) Presence of chloroplast in Chlamydomonas, allowing Chlamydomonas to photosynthesise ; 2. moves to optimum/best light intensity for photosynthesis ; OR 3. avoids damage to photosynthetic pigments due to very bright light ;

3 JPJC/JC2 H2 Biology/Prelim/2024 [Turn over (iii) Oligosaccharides are carbohydrates that contain three to ten monomers in their chain. Chlamydomonas use oligosaccharides to synthesise glycoproteins, which are transported to cell surface membranes. Describe the roles of the rough endoplasmic reticulum and the Golgi body in synthesising glycoproteins. [2] rough endoplasmic reticulum 1. Site of polypeptide/protein synthesis ; 2. polypeptide folding (in lumen and packaged in transport vesicles to Golgi body); A protein folding Golgi body 3. protein is further modified, sorted and packaged (into secretory vesicles in the lumen/cisternal space of Golgi body) ; rough endoplasmic reticulum or Golgi body 4. Proteins will undergo biochemical modifications including phosphorylation / glycosylation / attachment of, oligosaccharide / polysaccharide / carbohydrate ; (b) A Chlamydomonas cell has two flagella. These flagella contain a single type of protein. A flagellum consists of a bundle of 242 filaments. Each filament consists of 7500 protein molecules. Each protein molecul