2022 TJC JC2 H2 Biology Prelim P1 ANS

1 [Turn over TEMASEK JUNIOR COLLEGE 2022 JC2 PRELIMINARY EXAMINATION Higher 2 BIOLOGY 9744/01 Paper 1 Multiple Choice 15 September 2022 1 hour Additional Materials: Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Do not open this booklet until you are told to do so. Write your name, civics group and index number on the Multiple Choice Answer Sheet (MCAS). Write in soft pencil. Do NOT use staples, paper clips, glue or correction fluid. There are thirty questions on this paper. Answer all questions. For each question there are four possible answers A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the separate Answer Sheet. Read the instructions on the Answer Sheet very carefully. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. The use of an approved scientific calculator is expected, where appropriate. This document consists of 20 printed pages.

2 1 The diagram below shows the structures of a chloroplast, labelled R – W. Which combination of two structures could be used as evidence for the bacterial origin of chloroplasts? A U and R B S and V C U and W D W and T R S T U V W Based on the endosymbiont theory: Photosynthesis Lect Notes p.34 Evidences supporting Endosymbiont Theory: Strong evidences 1. Presence of 70S ribosomes which are also found in bacteria / are less dense than the eukaryotic 80S ribosomes. 2. Presence of multiple circular chromosomes/ DNA which are different from/ smaller than the linear chromosome/ nuclear DNA in eukaryotes. Other evidences 3. Presence of double membrane , suggesting that the ancient eukaryotic cell (outer membrane) engulfed the ancient prokaryotic cell (inner membrane). 4. The composition of the inner mitochondrial membrane (eg. presence of electron transport chain ) is the similar to those found in the cell surface membrane of prokaryotes. Outer membrane Chloroplast envelope granum Circular DNA 70s ribosome

3 [Turn over 2 A decrease in some factors will increase the fluidity of the cell surface membrane. Which pair of factors, when decreased, will increase the fluidity of the cell surface membrane? a decrease in A • distance between phospholipid molecules • proportion of short fatty acid chains INCORRECT:  fluidity means  distance between phospholipid molecules B • distance between phospholipid molecules • temperature C • proportion of phospholipids with saturated fatty acid chains • proportion of long fatty acid chains CORRECT: - saturated f.a. can be closely packed together - therefore  saturated f.a. will  fluidity -  long f.a chains will  hydrophobic interactions between phospholipids - this will  fluidity D • p