VJC 2021 H2 Bio 9744 P3 QP

1 VICTORIA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION 2021 HIGHER 2 NAME : ……………………………………………………….………………. CT CLASS: ………………..……… BIOLOGY Paper 3 Long Structured and Free-response Questions 9744/03 22/09/2021 2 hour Candidates answer on the Question Paper. Additional Materials: Answer Booklet READ THESE INSTRUCTIONS FIRST Write your name and CT 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 one question. Write your answer in the Answer Booklet provided. 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 bracket [ ] at the end of each question or part question. Question Marks Section A 1 2 3 Section B 4 or 5 Total This document consists of 16 printed pages. [Turn over]

2 Section A starts on page 3

3 Section A Answer all questions. 1 Drosophila are small flies in the order Diptera and family Drosophilidae. Commonly known as fruit or vinegar flies, they are often found on rotting fruit or other decaying matter. They are one of the most valuable organisms in biological research, particularly in genetics and developmental biology. The genome of Drosophila melanogaster comprised of eight chromosomes ( 2n=8), of which two of them are sex chromosomes. Like humans, the male is the heterogametic sex. Fig. 1.1 shows the chromosomes present in a male Drosophila. Fig 1.1 (a) (i) Circle the sex chromosomes in Fig. 1.1. [1] (ii) Explain what is meant by “heterogametic sex”. ……………………………………………………………………………………………….……... ………………………………………………………………………………………………….…... ……………………………………………………………………………………………….……... ………………………………………………………………………………………………….. [2]

4 Chromosomes contain the units of inheritance and their behavior during meiosis can be used to explain Mendel’s laws of inheritance. (b) Explain how the behavior of chromosomes during meiosis supports Mendel’s law of segregation and independent assortment. Law of segregation: ………………………………………………………………………..…………………………….. …………………………………………………………………………………..………………….. ………………………………………………………………………………………..…………….. ………………………………………………………………………………………..……….. [2] Law of independent assortment: ………………………………………………………………………………………………….…... ………………………………………………………………………………………………….…... ……………………………………………………………………………………………….……... ………………………………………………………………………………………………….. [2] Researchers studying the development of embryo in Drosophila noted the presence of mRNA codi