RI 2023 Prelim H2 Bio P1 QP

© RI 2023 Preliminary Examination 9744/01 [Turn over RAFFLES INSTITUTION 2023 Year 6 Preliminary Exam Higher 2 BIOLOGY 9744/01 Paper 1 Multiple Choice 28th Sept 2023 1 hour Additional Materials: Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name and shade your Index Number on the Answer Sheet in the spaces provided unless this has been done for you. There are thirty questions in this paper. Answer al l 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. (Erase all mistakes completely. Do not bend or fold the OMR Answer Sheet). This document consists of 21 printed pages. Raffles Institution Internal Examination

2 © RI 2023 Preliminary Examination 9744/01 1. The diagrams below show the results of an investigation into the composition of different mixtures of amino acids. Each mixture of amino acids was separated using chromatography. Each chromatogram was then turned 90 o and the amino acids were separated again by electrophoresis. Which diagram shows an amino acid mixture in which the solubility of some of the amino acids is the same but the charge on those particular amino acids is different? A B C D

3 © RI 2023 Preliminary Examination 9744/01 [Turn over 2. The enzyme invertase catalyses the breakdown of sucrose to glucose and fructose. Three different enzyme inhibitors of invertase, X, Y and Z were investigated. The percentage inhibition of invertase was measured at different concentrations of inhibitor. The graph shows the results of the investigation. What are valid conclusions based on the above results? 1 The higher the concentration of inhibitor X, the less sucrose is broken down. 2 The production of glucose and fructose when using inhibitor Y is higher than when using inhibitor Z. 3 The production of glucose and fructose at an inhibitor concentration of 2 arbitrary units is lower than at an inhibitor concentration of 4 arbitrary units, for all inhibitors. 4 X is the most effective inhibitor. A 4 only B 1 and 4 only C 2 and 3 only D 1, 2 and 4 only inhibitor X inhibitor Y inhibitor Z percentage inhibition inhibitor concentration / arbitrary units

4 © RI 2023 Preliminary Examination 9744/01 3. The distribution of membranes in the organelles of three cell types, a prokaryotic cell, a liver cell and an enzyme-secreting cell from the stomach, was determined. For each organelle, the amount of membrane is expressed as a percentage of the total amount of membrane in the cell. Which row of values best represents the membrane distribution in the three cell types? PM : plasma membrane rERM : rough endoplasmic reticulum membrane IMM : inner mitochondrial membrane OMM : outer mitochondrial membrane prokaryotic cell liver cell stomach cell PM rERM IMM PM rERM IMM PM rERM IMM A 99 0 0 35 7 28 60 16 4 B 99 0 0 35 7 28 60 4 16 C 52 12 36 60 7 28 35 4 16 D 52 12 36 60 28 7 35 4 16 4. The table below shows the concentrations of certain ions in sea water and in the cells of the marine alga Halicystis ovalis. ion concentration in sea water/ mmol dm-3 concentration in cell/ mmol dm-3 Na+ 488 257 K+ 12 337 Cl- 523 543 Ca2+ 12 2 Mg2+ 34 trace Which statement about the cells of H. ovalis is supported by the data? A Energy is required to move potassium ions into the cells. B H. ovalis cells use chloride ions in greater quantities than sodium ions. C Positively charged ions move into the cell more readily than negatively charged ions. D Sodium ions move out of the cell down their concentration gradient.

5 © RI 2023 Preliminary Examination 9744/01 [Turn over 5. The diagram shows the section through the cell surface membrane of a typical cell. When compared to the more fluid cell surface membrane of a phagocytic cell, a number of differences in the membrane composition can be observed. Which is the most likely set of differences that will be observed in the phagocytic cell? A a complete absence of component Q and a higher proportion of component P B a higher proportion of component S and a higher proportion of component T C a lower proportion of component V and a higher proportion of component U D an increased distance across R and a higher proportion of component V P Q R V U T S

6 © RI 2023 Preliminary Examination 9744/01 6. Many commercially produced bananas are triploid instead of diploid. Which of the following statements are incorrect? 1 As a result of triploidy, chromosomes cannot pair up during meiosis. 2 As a result of triploidy, non-disjunction occurs. 3 Mitosis cannot occur in triploid plants. 4 Sexual reproduction occurs more rapidly in triploid plants. 5 In order for a triploid organism to form, two triploid gametes need to fuse. A 1 and 4 only B 2 and 3 only C 3, 4 and 5 only D 2, 3, 4 and 5 only

7 © RI 2023 Preliminary Examination 9744/01 [Turn over 7. The diagram shows the cell cycle of a mammalian cell. Checkpoints in the cell cycle of mammals prevent the cycle from continuing when mistakes are made or when DNA is damaged. Four of the checkpoints are described below. 1 Mitosis is blocked if DNA replication is incomplete. 2 Anaphase is blocked if the attachment of chromatids to the spindle fibres is unsuccessful. 3 DNA replication is blocked if DNA is damaged. 4 DNA replication stops if damage to DNA has not been repaired. In which phases of the cell cycle do these checkpoints occur? checkpoint 1 2 3 4 A M G1 S G2 B G2 M G1 S C G2 S G1 M D S M G2 G1

8 © RI 2023 Preliminary Examination 9744/01 8. Bacteria were cultured in a medium containing heavy nitrogen ( 15N) until all the DNA was labelled. These bacteria were then grown in a medium containing only normal nitrogen (14N) for 5 generations. The percentage of 14N DNA strands in each generation was estimated. Which curve provides evidence that DNA replication is semi-conservative? 9. The diagram below shows a particular stage in protein synthesis in eukaryotes. Which of the following statements is true of structures X and Y? A Structure X is double stranded whereas structure Y is single stranded. B There is hydrogen bond interaction between all the subunits of both structures X and Y. C The information on structure Y is used to synthesize structure X. D The coiling of structure Y is a direct result of the information on structure X. 0 25 50 75 100 0 1 2 3 4 5 Generation A B C D Percentage of 14N DNA structure X structure Y

9 © RI 2023 Preliminary Examination 9744/01 [Turn over 10. The