TMJC 2023 H2 P3 QP

CANDIDATE NAME CIVICS GROUP H2 BIOLOGY 9744/03 Paper 3 Long Structured and Free-response Questions 18 September 2023 2 hours Candidates answer on the Question Paper. No additional materials are required. READ THESE INSTRUCTIONS FIRST Write your name and Civics Group in the spaces at the top of the 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. Section A Answer ALL questions. Section B Answer ONE question. 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. ______________________________________________________________________________________ This document consists of 19 printed pages and 1 blank page. For examiner’s Use Section A 1 / 30 2 / 20 Section B 3 or 4 / 25 Total / 75 TAMPINES MERIDIAN JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION

2 Tampines Meridian Junior College 2023 JC2 Preliminary Examination H2 Biology Section A Answer all questions in this section. 1 (a) The pituitary gland is located in the brain of mammals. Prolactin, a hormone from the pituitary gland, stimulates cells in the mammary glands of female mammals so that the cells are able to secrete milk. (i) State the potency of the stem cells that produce pituitary cells. [1] ..………………………………………………………………………………………………… (ii) With reference to the information provided, explain how the stem cells in pituitary gland stimulate cells in the mammary gland to secrete milk. [3] ..………………………………………………………………………………………………… .…………………………………………………………………………………………………. .…………………………………………………………………………………………………. ………………………………………………………………………………………………….. .…………………………………………………………………………………………………. ………………………………………………………………………………………………….. .…………………………………………………………………………………………………. (iii) Cells in the mammary glands that have been stimulated by prolactin need more glucose. State one reason why those cells need more glucose. [1] ………………………………………………………………………………………………….. .………………………………………………………………………………………………….

3 Tampines Meridian Junior College 2023 JC2 Preliminary Examination H2 Biology (b) Female mammals produce milk to feed new-born offspring. Secretory Immunoglobulin A (SIgA) is the main antibody found in breast milk of humans. It is secreted from IgA-producing plasma cells into cavities within the mammary glands to form milk with other components. (i) Explain how newly synthesi sed SIgA in the IgA -producing plasma cells reach the cavities within the mammary glands. [4] ……………………………