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 • proportion of phospholipids with unsaturated fatty acid chains • temperature 3 Equal sized potato pieces were placed into test -tubes containing equal volumes of different concentrations of sucrose solution and left for 30 minutes. All other variables were controlled. After 30 minutes , the potato piece in one of the concentrations of sucrose solution had not changed in size. What can be concluded from this result? 1 There is no net movement of water into or out of the potato. TRUE: amount of water molecules moving in = moving out 2 The water potential of the potato is the same as the water potential of the sucrose solution. TRUE: → no net movement of water 3 The concentration of sucrose in the potato is the same as the concentration of the sucrose solution. FALSE: CANNOT be determine. Because ions and other sugars contribute to the water potential of the cell sap. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 only

4 4 The diagram shows the results of a number of tests on a solution of biochemicals. Which substances are present in the solution? A amylose, amylopectin and lipid B glucose, starch and catalase C sucrose, amylase and triglyceride D sucrose, starch and catalase sucrose – non-reducing sugar catalase - protein solution of biochemicals Benedict’s test blue non-reducing sugar test yellow iodine test blue-black biuret test purple Reducing sugar absent Non-reducing sugar present Starch present Protein present

5 [Turn over 5 The diagram shows part of the chemical structure of a naturally occurring polysaccharide. What types of glycosidic bonds are present? A α-1,3 and α-1,4 B α-1,4 and α-1,6 C β-1,3 and β-1,4 D β-1,4 and β-1,6 1 1 2 3 4 1 2 3 α(1-4) glycosidic β(1-4) glycosidic (alternate glucose rotated) β(1-4) glycosidic (not rotated) β(1-4) glycosidic (rotated)

6 6 The graph shows the results of an experiment in which samples containing the same concentration of enzyme and substrate were kept at different temperatures for periods of one, two, and five hours. The quantities of product formed were then determined. Which of the following option best explains why the optimum temperature is lower if the quantity of product formed is measured after five hours rather than one hour? A Tertiary bonds are not broken at higher temperatures. B The enzyme has a range of optimum temperatures. C A longer time at high temperature denatures enzyme. D The optimum temperature for the enzymes is 45˚C. quantity of product formed / arbitrary units temperature / ˚C 0 10 20 30 40 50 60 After 1 hour, test for amt of products in each tube 2 hours 5 hours Note: Leaving enzymes at a longer time at higher temp  more denatured 35oC instead of 45oC

7 [Turn over 7 An enzyme is completely denatured at 50˚C. A fixed concentration of this enzyme is added to a fixed concentration of its substrate. The time taken for completion of the reaction is measured at different temperatures. Which graph shows the results? 8 The rate of aerobic cellular respiration in a human cell may increase if the A temperature of the cell is lowered from 37˚C to 35˚C. B oxygen concentration available to the mitochondria increases. CORRECT: oxygen is the final electron acceptor C carbon dioxide concentration in the cytosol of the cell increases. D rate of facilitated diffusion of glucose into the cytosol of the cell decreases. INCORRECT: glucose is the respiratory substrate   glucose will  rate A B C D Note: - faster reaction  shorter time taken - optimum temp  shortest time - if enzymes are denatured  longest time taken -

8 9 The diagram below shows a section through a part of a mitochondrion. The sites of the pathways in aerobic respiration are glycolysis in cytosol Krebs cycle mitochondria matrix electron transport chain inner mitochondrial membrane A R S T B U T R C R U T D T R S 10 Which one of the following diagrams correctly represents the inputs and outputs of photosynthesis? A B C D outside mitochondrion inside mitochondrion matrix Inter-membrane space cytosol Products of light rxn: - ATP - NADPH

9 [Turn over 11 During prophase, a scientist stains the chromosomes of a diploid animal cell with a fluorescent dye to stain telomeres. This cell has 32 chromosomes. How many telomeres will the scientist observe? A 32 B 64 C 96 D 128 12 Which process(es) involve(s) mitosis? clonal selection of T-lymphocytes forming cells at the tip of a growing root replacing skin cells damaged by an injury After DNA replication  each chromosome has a pair of sister chromatids One chromosome with 4 telomeres 32 chromosomes = 32 X 4 = 128

10 13 A drug ha