2025 ASRJC H2Bio PE P2 (ANS)

ASRJC BIOLOGY DEPT 9744/2025/J2PRELIM/P2 [Turn over H2 ANDERSON SERANGOON JUNIOR COLLEGE HIGHER 2 2025 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. 22 AUGUST 2025 FRIDAY 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 31 printed pages and 1 blank page. For Examiner’s Use 1 / 9 2 / 9 3 / 11 4 / 10 5 / 10 6 / 9 7 / 10 8 / 10 9 / 10 10 / 7 11 / 5 Total /100

2 ASRJC BIOLOGY DEPT 9744/2025/J2PRELIM/P2 Answer all the questions. 1 Stem cells are found throughout the human body. Lgr5 + stem cells are found in the lining of the small intestine. Fig. 1.1 is a flow chart showing stages in the development of one of the daughter cells produced by the mitotic division of an Lgr5+ stem cell. Fig. 1.1 (a) Explain why Lgr5+ stem cells are required in the lining of the small intestine. [3] any two from: I repair cells 1. to replace (old / worn-out / dead / short-lived) cells / repair (damaged) tissue ; 2. (damaged by) movement of food through intestine / presence of pathogens, 3. stem cells divide and differentiate to become specialised ; A form different types of cells 4. cells (produced by stem cells) are genetically identical so the function of the small intestine can continue 5. idea of self-renewal of stem cells/ stem cells divide via mitosis to maintain the, pool / number, of stem cells ; (I increase in number of stem cells) 6. AVP idea that allows growth (of small intestine) during development (R growth of cells)

ASRJC BIOLOGY DEPT 9744//2025/J2PRELIM/P2 Fig. 1.2 shows one of the specialised cells, goblet cell that develops from Lgr5+ stem cells in the small intestine. Fig. 1.2 (