NJC 2023 H2 Biology Prelim P3 QP

©NJC 2023 9744/03/SH2/H2/Biology/Preliminary Examination [Turn over NATIONAL JUNIOR COLLEGE, SINGAPORE Senior High 2 Preliminary Examination Higher 2 CANDIDATE NAME BIOLOGY CLASS 2bi2___ REGISTRATION NUMBER BIOLOGY Paper 3: Long Structured and Free-response Questions Candidates answer on the Question Paper and Answer Booklet No Additional Materials are required. 9744/03 25 August 2023 2 hours READ THESE INSTRUCTIONS FIRST Write your name and Biology class 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. Section A Answer all questions in the spaces provided on the Question Paper. Section B Answer any one question in the Answer Booklet. The use of an approved scientific calculator is expected, where appropriate. You may lose marks if you do not show your workings or if you do not use appropriate units. The number of marks is given in the brackets [ ] at the end of each question or part question. For Examiner’s Use Section A 1 /30 2 /10 3 /10 Section B 4/5 /25 Total /75 This document consists of 14 printed pages and 2 blank pages.

2 ©NJC 2023 9744/03/SH2/H2/Biology/Preliminary Examination Section A Answer all the questions in this section. 1 FoxO1 is a protein found in pancreatic β cells. Fig.1.1 shows a model of FoxO1. Fig. 1.1 (a) Describe how monomers may be linked together to form the FoxO1 polypeptide chain. Make bottom border for writing. [2] (b) Explain how amino acids that are spaced far apart in the Fox O1 polypeptide chain may be brought together in its 3-dimensional structure. [4]

3 ©NJC 2023 9744/03/SH2/H2/Biology/Preliminary Examination [Turn over Diabetes is often associated with the failure of the β (beta) cells in the pancreas, but it is unclear what actually causes this failure. Some studies have suggested that this failure may be related to FoxO1. A study was conducted using mice lacking the gene for FoxO1 in β cells (IKO) as well as normal (control) mice. Blood glucose levels after fasting were compared for four groups of mice: young (3 months old) male mice, young (3 months old) female mice, older females (who have had several pregnancies) and aging males (16–20 months). The results are shows in Fig. 1.2. Fig. 1.2 (c) Describe and explain the blood glucose levels after fasting between young control mice and young IKO mice without FoxO1. [3]

4 ©NJC 2023 9744/03/SH2/H2/Biology/Preliminary Examination (d) Aging and having pregnancies are considered to be physiological stresses. Describe and explain the effect of stress on blood glucose levels in control mice. Make bottom border for writing. [3] (e) Insulin and glucagon are hormo