2022 HCI JC2 H2 Biology Prelims Paper 1 QP

HWA CHONG INSTITUTION JC2 Preliminary Examinations Higher 2 CANDIDATE NAME CT GROUP 21S7___ CENTRE NUMBER INDEX NUMBER BIOLOGY Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet 9744/01 20 September 2022 1 hour INSTRUCTIONS TO CANDIDATES 1. Write your name, CT group, Centre number and index number in the spaces provided at the top of this cover page. 2. Fill in your particulars on the Multiple Choice Answer Sheet. Write your NRIC number and shade accordingly. 3. 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. 4. At the end of the paper, you are to submit only the Answer Sheet. INFORMATION FOR CANDIDATES 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 used of an approved scientific calculator is expected, where appropriate. This document consists of 22 printed pages.

2 © Hwa Chong Institution 2022 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 1 The electronmicrograph shows part of a eukaryotic cell with structures labelled A, B, C and D. Which statement is correct? A Rough endoplasmic reticulum divides the cytoplasm into compartments and is studded with numerous ribosomes, which synthesise proteins. B Mitochondrion is an energy transducer where fats and sugars are reduced to produce ATP. C Cytoplasm is an aqueous matrix containing proteins and DNA for transcription. D Euchromatin is a loosely coiled form of chromatin that is associated with proteins called histones. 2 What are the essential structural features of viruses? 1 non-cellular 2 protein coat 3 both DNA and RNA 4 either DNA or RNA A 1, 2 and 3 B 1, 2 and 4 C 1 and 3 only D 2 and 4 only A D C B

3 © Hwa Chong Institution 2022 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 3 Which row correctly describes the primary, secondary, tertiary and quaternary structures of some proteins? primary structure secondary structure tertiary structure quaternary structure A determines the folding of the polypeptide depends on hydrogen bonding between the side- chains of amino acids defines the overall shape and folding of the protein formed when two or more identical polypeptides join together B defines the order of amino acids in the polypeptide usually forms immediately after polypeptide synthesis is held together by all the types of bonding that occur in proteins found in globular proteins such as haemoglobin but never in fibrous proteins C involves covalent bonds only involves hydrogen bonding essential for the function of enzymes and receptors formed when two or more polypeptides join together D involves peptide bonds between the side-chains of amino acids involves folding between local regions within a polypeptide molecule changes reversibly when bound to non- competitive inhibitors can involve hydrogen bonds, covalent bonds and hydrophobic interactions

4 © Hwa Chong Institution 2022 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 4 The diagram shows par t of a cell surface membrane. The arrow shows the path taken by potassium ions when they diffuse through the membrane out of a cell. The graph shows how the rate of diffusion of potassium ions across the cell surface membrane is affected by the concentration of potassium ions within the cells. Which row is correct? region W to X: limiting factor on the rate of diffusion region Y to Z: limiting factor on the rate of diffusion A concentration of potassium ions inside the cell number of potassium channels B number of potassium channels concentration of potassium ions outside the cell C concentration of potassium ions inside the cells slower rate of potassium ions passing through the channels D concentration of potassium ions outside the cell minimum rate of potassium ions passing through the channels W X Y Z rate of diffusion concentration of potassium ions inside cell intracellular region extracellular region potassium ions

5 © Hwa Chong Institution 2022 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 5 The graph shows how the concentration of components of an enzyme-catalysed reaction changes with time. Which row is correct? enzymes with empty active sites substrates products enzyme-substrate complexes A 1 2 4 3 B 2 3 1 4 C 4 1 3 2 D 3 4 2 1 1 2 3 4 concentration time

6 © Hwa Chong Institution 2022 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 6 Catechol oxidase is an enzyme found in fruits that oxidises catechol into a quinone, which causes browning. Commercial catechol oxidase could be inhibited by the following chemicals:  parahydroxybenzoic acid (PHBA), a chemical structurally similar to catechol  pheynlthiourea (PTU), which binds to a copper atom in the enzyme away from the active site. Which graph correctly shows the activity of the two inhibitors? A B key: No inhibitors PHBA PTU C D 7 Which statements are true about stem cells? 1 Stem cells extracted from any tissue can immediately differentiate into skin cells with the introduction of appropriate transcription factors. 2 One potential side effect of any stem cell-based therapy is the formation of a tumour. 3 Human embryonic stem cells are removed at an early stage of embryonic development from a region of the blastocyst known as the inner cell mass. 4 Any stem cell can develop into a whole organism when implanted into the uterus. A 1 and 2 B 2 and 3 C 1, 3 and 4 D 2, 3 and 4 rate of reaction rate of reaction rate of reaction rate of reaction substrate concentration substrate concentration substrate concentration substrate concentration

7 © Hwa Chong Institution 2022 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 8 The diagram shows the structure of a nucleotide that can fit the active site of DNA polymerase. Which statement predicts the effect that the nucleotide has on DNA replication? A The nucleotide cannot be added to the 3’ end of the growing DNA strand. B The nucleotide can be added to the 3’ end of the growing DNA strand but will not allow the next nucleotide to be added to it. C The nucleotide can be added to the 3’ end of the growing DNA strand and will also allow the next nucleotide to be added to it. D The nucleotide can be added to the 3’ end of the growing DNA strand and will also allow the next nucleotide to be added to it, but it will be replaced by upstream DNA synthesis later. 9 Some of the stages of transcription in a eukaryotic cell are listed. 1 TATA box binding protein binds to the promoter on DNA. 2 A poly(A) signal is transcribed. 3 RNA polymerase dissociates from the transcription initiation complex. 4 Twenty-three nucleotides of RNA are synthesised allowing the transcription initiation complex to move away from the core promoter. 5 General transcription factors and RNA polymerase bind at promoter on DNA, forming the transcription initiation complex. Using the information provided above, what is the order in which these stages occur? A 1  5  2  3  4 B 1  5  4  3  2 C 5  1 