2024 ACJC H2 Bio P2 QP

This document consists of 30 printed pages. [Turn over Anglo-Chinese Junior College JC2 Biology Preliminary Examination Higher 2 CANDIDATE NAME FORM CLASS TUTORIAL CLASS I N D E X NUMBER BIOLOGY Paper 2 Structured Questions Candidates answer on the Question Paper. No Additional Materials are required. 9744/02 22 August 2024 2 hours READ THESE INSTRUCTIONS FIRST Write your Name, Class and Index number 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 Examiners’ use only 1 / 8 2 / 10 3 / 11 4 / 10 5 / 11 6 / 9 7 / 10 8 / 10 9 / 10 10 / 5 11 / 6 Total / 100

2 Anglo-Chinese Junior College 2024 J2 H2 9744 Paper 2 Preliminary Examination For Examiner Use Answer all questions. 1 Fig. 1.1 is an electron micrograph of a cell found in the human adrenal cortex which secretes the hormone adrenaline into the bloodstream. Fig. 1.1 (a) (i) Identify organelle P. …………………………………………………………………………………………………. [1] (ii) Describe how organelle P is involved in the secretory process of the cell in Fig. 1.1. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. …………………………………………………………………………………………………. [2]

3 [Turn over Anglo-Chinese Junior College 2024 J2 H2 9744 Paper 2 Preliminary Examination For Examiner Use (b) Cells expressing proteins of interest are allowed to take up radioactively labeled amino acids for a brief interval, during which all newly synthesised protei ns will exhibit a certain level of radioactivity. Fig. 1.2. shows the percentage of radioactivity found in three organelles of the endomembrane system, X, Y and Z within the span of two hours. Fig. 1.2 ( i ) Identify organelle Y. …………………………………………………………………………………………………. [1] (ii) Using Fig. 1.2, account for the level of radioactivity in organelle Y. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. …………………………………………………………………………………………………. [2]

4 Anglo-Chinese Junior College 2024 J2 H2 9744 Paper 2 Preliminary Examination For Examiner Use (iii) Bafilomycin A1 is a chemical inhi bitor that blocks the process of exocytosis at the cell surface membrane. This causes a change in one of the graphs in Fig 1.2. On Fig. 1.2, sketch a graph that represents this expected change. [1] ( i v ) Explain your answer in (b)(iii). …………………………………………………………………………………………………….. ………………………………………………………………………………………….............[1] [Total: 8]

5 [Turn over Anglo-Chinese Junior College 2024 J2 H2 9744 Paper 2 Preliminary Examination For Examiner Use 2 Collagen plays a structural role and contributes to mechanical properties and shape of tissues in the body. Fig. 2.1 shows the approximate co mposition of collagen and the molecular structure of four of the amino acids found in it. Fig. 2.1 (a) (i) With reference to Fig. 2.1, explain why collagen is an insoluble protein. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. …………………………………………………………………………………………………..[3] composition in collagen / % amino acids

6 Anglo-Chinese Junior College 2024 J2 H2 9744 Paper 2 Preliminary Examination For Examiner Use (ii) Explain why the abundance of glycine in collagen is essential for its function. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. …………………………………………………………………………………………………..[3] (b) Fig. 2.2 shows how changes in concentration of oxygen affects its binding to haemoglobin. Fig. 2.2 ( i ) State the property of haemoglobin that is illustrated in Fig. 2.2. …………………………………………………………………………………………………. [1] oxygen binding to haemoglobin / % oxygen concentration / mm Hg

7 [Turn over Anglo-Chinese Junior College 2024 J2 H2 9744 Paper 2 Preliminary Examination For Examiner Use (ii) Using your knowledge of the struct ure of haemoglobin, explain h ow the property stated in (b)(i) enhances its function. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. …………………………………………………………………………………………………. [3] [Total: 10]

8 Anglo-Chinese Junior College 2024 J2 H2 9744 Paper 2 Preliminary Examination For Examiner Use 3 Fig. 3.1 shows the fluid mosaic model of cell surface membrane. Fig. 3.1 ( a ) Identify structures labelled A and B in Fig. 3.1. A ………………………………………………………………………………………………………… B ………………………………………………………………………………………………………… [2] ( b ) Explain why the structure of C varies across different membranes in a cell. ………………………………………………………………………………………………………....... ………………………………………………………………………………………………………....... ………………………………………………………………………………………………………....... ………………………………………………………………………………………………………....... ………………………………………………………………………………………………………...[2] A B C

9 [Turn over Anglo-Chinese Junior College 2024 J2 H2 9744 Paper 2 Preliminary Examination For Examiner Use ( c ) Table 3.1 shows the results from a study on the mean percentage of cholesterol found in the cell surface membrane of epithelial skin cells of different animals. Table 3.1 animal mean percentage of cholesterol in cell surface membrane of epithelial skin cell giraffe 10 rhinoceros 12 eurasian mouse 15 scottish blackface sheep 18 antarctic penguin 28 african elephant 8 arctic fox 30 ( i ) Suggest why arctic foxes have a greater mean percentage of chol esterol in their cell surface membranes than giraffes. …………………………………………………………………………………………................. …………………………………………………………………………………………................. …………………………………………………………………………………………................. …………………………………………………………………………………………................. ………………………………………………………………………………………….............[2] (ii) Estimate, with a reason, the percentage of cholesterol that wou ld be found in the cell surface membranes of polar bears. …………………………………………………………………………………………................. ……………………………………………………………………