2024 NYJC Prelim Biology P3 (Q)

NANYANG JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME CLASS BIOLOGY 9744/03 Paper 3 Long Structured and Free-response Questions 13 September 2024 Additional Materials: Insert, Answer booklet 2 hours READ THESE INSTRUCTIONS FIRST Write your name and CT on all the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, highlighters, glue or correction fluid. Section A Answer all questions in the spaces provided on the Question Paper. Section B Answer any one question on the separate Answer 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 no 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. For Examiner’s Use Section A 1 2 3 Section B Total This document consists of 13 printed pages. [Turn over H

2 9744 / H2 Biology / 03 Section A Answer all the questions in this section. 1 Part of the information required for Question 1 is presented in the insert. Cross references to Fig. 1.1 and Fig. 1.2 are included in the questions for which Fig. 1.1 and Fig. 1.2 are relevant. Bioinformatics is the collection, processing and analysis of biological data using computer software. The application of bioinformatics allows whole sequences of homologous genes to be compared across different bacterial species. (a) Explain why bioinformatics can used to compare gene sequences and suggest a conclusion that can be made from the percentage similarity data obtained. [2] (b) Humans use antibiotics to treat bacteria infections. Different types of antibiotics work i n different ways to either kill or inhibit the reproduction of the bacteria. (i) Outline how penicillin acts on bacteria and use Fig. 1.1 to suggest why penicillin has little or no effect at treating diseases caused by Gram-negative bacteria. [3]

3 9744 / H2 Biology / 03 (ii) The use of antibiotics has resulted in the emergence of antibiotic resistant bacteria. Antibiotics such as nalidixic acid acts as an inhibitor of an enzyme involved in DNA replication. Suggest how a substitution mutation in the gene coding for this enzyme could result in antibiotic resistance. [4] (c) The outer membrane of E.coli contains transport proteins called OmpF porins. These porins allow the passive movement of water, ions and small, polar molecules across the outer membrane. Each OmpF porin is formed from three identical polypeptides. (i) Suggest and explain the features of an OmpF porin as a membrane transport protein. [4]

4 9744 / H2 Biology