TJC 2023 H2 BIO P2 ANS

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 2023 JC2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME ANSWERS CENTRE NUMBER S INDEX NUMBER BIOLOGY 9744/02 Paper 2 Structured Questions (Part I) 25 AUGUST 2023 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 / 12 2 / 11 3 / 11 4 / 10 5 / 8 Answer all questions. This document consists of 16 printed pages.

2 Answer all questions. 1 Fig. 1.1 shows an electron micrograph of a plant cell. Fig. 1.1 (a) Identify the organelles labelled A, B, and C in Fig. 1.1. A: Nucleus B: Chloroplast C: Vacuole [3] (b) Use a line to label the cell wall, D. [1] (c) The magnification of the photomicrograph is 560x. Calculate the actual length of organelle C in μm, along the line P-Q. Show your working. Length of PQ = 74 mm [1/2] (A: 73, 74, 75 mm) Actual length of organelle C = length of image magnification [1/2] = 𝟕𝟕𝟕𝟕×𝟏𝟏 𝟎𝟎𝟎𝟎𝟎𝟎 𝝁𝝁𝝁𝝁 𝟓𝟓𝟓𝟓 𝟎𝟎 = 𝟏𝟏𝟏𝟏𝟏𝟏. 𝟏𝟏 𝝁𝝁𝝁𝝁 (A: 132.14 for 2 d.p.) actual length of organelle C: 132.1 [1] μm [2] [1/2] – formula [1/2] – state measurement of length PQ [1] – correct final answer (number) on the line provided D

3 [TURN OVER (d) Compare the structural features of organelle A and organelle B. [2] Similarities [any 1]: 1. Both of them are bound by double membrane. 2. Both of them contain DNA (and RNA). Differences [any 1]: 3. Nucleus has linear DNA while chloroplast has circular DNA. 4. Nucleus does not thylakoids while chloroplast has thylakoid membranes inside. 5. Nucleus does not contain ribosomes but chloroplast contain 70S ribosomes. 6. Presence of chlorophyll pigments/photosystems in chloroplasts vs absent in nucleus 7. Nucleus is larger / denser than chloroplast. AVP: A outer membrane is continuous with RER, but not B B has electron carriers / ATP synthase but not A B has starch grains but not A (e) A factor that can limit the rate of photosynthesis is the rate of regeneration of RuBP. Sedoheptulose-1,7-bisphosphatase (SBPase) is an enzyme in the Calvin cycle that controls the rate of regeneration of Ru