TJC 2023 H2 BIO P1 ANS

1 [Turn over TEMASEK JUNIOR COLLEGE 2023 JC2 PRELIMINARY EXAMINATION Higher 2 BIOLOGY 9744/01 Paper 1 Multiple Choice 15 September 2023 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. 1 B 2 A 3 A 4 B 5 A 6 A 7 B 8 C 9 A 10 B 11 C 12 A 13 D 14 C 15 B 16 C 17 A 18 D 19 D 20 C 21 B 22 B 23 B 24 B 25 C 26 D 27 C 28 A 29 B 30 A This document consists of 15 printed pages and 1 blank page.

2 1 Which statement regarding the cell theory is false? A All living organisms are made up of one or more cells. B All cells must contain either DNA or RNA. C The cell is the basic structural and functional unit of life. D All cells arise from pre-existing cells. 2 The graph shows how the rate of entry of glucose into a cell changes as the concentration of glucose outside the cell changes. What is the cause of the plateau at X? A All the carrier proteins are saturated with glucose. B The carrier proteins are denatured and no longer able to function. C The cell has used up its supply of ATP. D The concentrations of glucose inside and outside the cell are equal. rate of entry of glucose into the cell concentration of glucose outside the cell X

3 [Turn over 3 Diagrams 1, 2 and 3 show the structural formulae of three polysaccharides. What are the names of these polysaccharides? 1 2 3 A amylose cellulose glycogen B amylose glycogen cellulose C cellulose glycogen amylose D glycogen amylose cellulose 4 Which statements about phospholipids and triglycerides are correct? 1 They both contain ester bonds. 2 They both have three fatty acid chains per molecule. 3 They both may have saturated and unsaturated fatty acid chains. 4 They are both used only as storage molecules. A 1, 2 and 3 B 1 and 3 only C 2, 3 and 4 D 2 and 4 only

4 5 The four acids shown below form part of an enzyme-catalyzed sequence of reactions. The addition of malonic acid results in no change in the concentration of oxoglutaric acid, an accumulation of succinic acid, and a near absence of both fumaric acid and malic acid. Further addition of fumaric acid results in the formation of malic acid. What does this information indicate about malonic acid? A It is an inhibitor of enzyme 2. B It catalyses the formation of succinic acid. C It is an inhibitor of enzyme 1. D It reacts with fumaric acid. 6 Two experiments, X and Y, were carried out using an enzyme from humans. Experiment X was carried out at a constant temperature of 37°C while experiment Y was carried out a constant temperature of 80°C. All other factors were kept the same. Which graph shows the results?

5 [Turn over 7 The diagram shows the path taken by electrons and the formation of hydrogen ions in the light- dependent stages of photosynthesis. What are the electrons and hydrogen ions used to produce? A ATP from ADP B ATP from ADP and reduced NADP from NADP C glycerate-3-phosphate from glyceraldehyde-3-phosphate D reduced NADP from NADP 8 In light, Mg2+ ions move into the stroma. In the dark, the concentration of Mg2+ ions in the stroma is low. In high Mg 2+ concentrations, CO 2 and Mg 2+ react with the active site of RuBP carboxylase (rubisco), making a carbamate group (C0 2NH) and making the rubisco active. In low Mg 2+ concentrations the carbamate group dissociates making the rubisco inactive. Inactive rubisco will bind tightly at its active site with any RuBP present, so that no rubisco catalysis can take place. An ATPase enzyme called rubisco activase, can, in high concentrations of Mg2+, release the RuBP from the rubisco, producing a carbamate group and activating the rubisco. Which statement is supported by these facts? A Inactivated rubisco can be reactivated by NADPH made in the light-dependent reaction. B Low concentrations of 3C compound in the stroma of the chloroplast deactivate rubisco. C Rubisco without the carbamate group is inhibited by low concentrations of RuBP. D The rate of carbon dioxide fixation increases when the carbamate group dissociates from rubisco. increase in energy of electrons electron acceptor electron acceptor light light

6 9 Cyanide is a poison that blocks the passage of electrons along the electron transport chain. Assuming that all other conditions are optimal, which one of the following options would see an effect on ATP synthesis with the addition of cyanide? A Chloroplast suspension illuminated by light. B Cytoplasm lacking in organelles incubated with lactate. C Cytoplasm lacking in organelles incubated with pyruvate. D Mitochondria suspension incubated with fructose 1,6 bisphosphate. 10 Methotrexate is a drug used to treat cancer. It can act as an enzyme inhibitor preventing the synthesis of nucleotides containing thymine. Cells treated with methotrexate are not able to complete the cell cycle. A cell entering telophase is treated with methotrexate. Which stage of the cell cycle will be affected by the action of methotrexate? A anaphase B interphase C metaphase D prophase

7 [Turn over 11 Stem cells can be used to replace cells in damaged tissues, such as skin. The diagram shows two ways in which replacement skin cells can be produced. Which row correctly describes the stem cells P, Q and R? P Q R A pluripotent multipotent totipotent B pluripotent induced pluripotent induced pluripotent C totipotent pluripotent induced pluripotent D totipotent totipotent totipotent 12 In eukaryotic cells, nucleic acids are found in organelles other than the nucleus. Which of the following is correct? chloroplast endoplasmic reticulum ribosome mitochondrion A DNA and RNA RNA DNA and RNA B DNA DNA DNA and RNA C DNA and RNA RNA DNA D RNA DNA and RNA RNA

8 13 Telomerase is an enzyme that adds nucleotides to telomeres. Which statement about telomerase is correct? A A high concentration of telomerase in a cell damages genes during DNA replication. B A high concentration of telomerase in cancerous cells limits the rate of tumour growth. C The low concentration of telomerase in stem cells means that these cells can divide an unlimited number of times. D The low concentration of telomerase in body cells means that these cells can divide a limited number of times. 14 A bacterial circular DNA molecule is 2 600 150 base pairs long. 26% of these bases are adenine. How many cytosine bases would be in the DNA molecule? A 624 036 B 676 039 C 1 248 072 D 1 352 078 15 The table shows a comparison of some aspects of the genomes and protein-coding genes of the prokaryote bacterium, Escherichia coli and the eukaryote fungus Saccharomyces cerevisiae. E. coli S. cerevisiae Genome length / base pairs 4 640 000 12 068 000 Number of protein-coding genes 4300 5800 Proteins with roles in: Metabolism 650 650 Energy release / storage 240 175 Membrane transport 280 250 Transcription 240 400 Translation 180 350 Cell structure 180 250 What could not account for the differences in the number of protein-co