2024 JPJC Prelim H2 Biology P1 (Q)

9744 / 01 [Turn over NAME : CLASS : JURONG PIONEER JUNIOR COLLEGE JC2 Preliminary Examination 2024 BIOLOGY Higher 2 9744/01 17 September 2024 Paper 1 Multiple Choice 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, class and index number on the Answer Sheet in the spaces provided unles s this has been done for you. 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 21 printed pages and 3 blank pages.

2 JPJC/JC2 H2 Biology/Prelim/2024 1 Which eukaryotic cell structures all contain nucleic acids? A centrioles, chloroplasts, mitochondria, ribosomes B centrioles, mitochondria, nuclei, ribosomes C chloroplasts, mitochondria, cytoplasm, ribosomes D cytoplasm, Golgi bodies, mitochondria, nuclei 2 Mimivirus is one of many giant viruses that have recently been discovered. It has about a thousand protein-coding genes. Some scientists think that Mimivirus evolved from ancient bacteria. The genes of Mimivirus include those for: 1 light-driven proton pumps 2 Krebs cycle enzymes 3 ribosomal-binding sites 4 enzymes for linking nucleic acids to amino acids. Which Mimivirus genes are also found in anaerobic gut bacteria in humans? A 1, 2, 3 and 4 B 1 and 2 only C 2 and 4 only D 3 and 4 only

3 JPJC/JC2 H2 Biology/Prelim/2024 [Turn over 3 What is true about carbohydrates found in animals? 1 β-glucose monomers are used to synthesise cellulose. 2 Glucose, ribose and deoxyribose are monosaccharides. 3 Glycogen is insoluble in water. 4 All carbohydrates are reducing sugars. A 1, 2 and 3 B 1 and 2 only C 1 and 4 D 2 and 3 only 4 Which statements about ester bonds are correct? 1 Condensation between glycerol and fatty acids uses water and forms triglyceride. 2 Triglyceride forms three ester bonds through condensation. 3 Phospholipids and triglycerides contain ester bonds. 4 The hydrolysis of triglyceride releases saturated fatty acids and glycerol. A 1, 2, 3 and 4 B 1, 2 and 3 only C 1 and 4 only D 2 and 3 only

4 JPJC/JC2 H2 Biology/Prelim/2024 5 The cells in the roots of beetroot plants contain a red pigment. When pieces of root tissue are soaked in cold water, some of the red pigment l eaks out of the cells into the water. An experiment was carried out to investigate the effect of temperature on the loss of red pigment from the root cells. It was found that the higher the temperature of the water, the higher the rate of loss of red pigment from the root cells. Which statements could explain this trend? 1 Enzymes in the cells denature as the temperature increases, so the pigment can no longer be used for reactions inside the cells and diffuse out. 2 As the temperature increases, the tertiary structure of protein molecules in the cell surface membrane changes, increasing the permeability of the membrane. 3 Phospholipid molecules gain kinetic energy as the temperature rises, increasing the fluidity of the phospholipid bilayer and allowing pigment molecules to diffuse out more easily. A 1 and 2 B 2 and 3 C 2 only D 3 only

5 JPJC/JC2 H2 Biology/Prelim/2024 [Turn over 6 Glutamine is a polar amino acid found in many globular proteins. Within a si ngle polypeptide chain of a globular protein, bonds can form between two glutamine amino acids that are widely separated in the amino acid sequence. These bonds can help to stabilise the secondary and tertiary structure of the protein. Which row shows the type of bond formed between these glutamine amino acids and where in the protein these bonds are most likely to be located? type of bond location in the protein A hydrogen bond inner core B hydrogen bond outer edge C hydrophobic interaction inner core D hydrophobic interaction outer edge 7 The diagram shows sucrose and sucralose. The enzyme sucrase breaks down sucrose but cannot break down sucralose. Four students were asked to suggest why sucrase can break down sucrose but not sucralose. Three of the students gave correct suggestions. Which suggestion is not correct? A The Cl atoms change the shape of the sucralose molecule so it is not the same shape as the active site of sucrase. B The Cl atoms of the modified fructose cannot bind to the active site of sucrase. C The Cl atoms cannot cause an induced fit, so sucralose does not enter the active site of sucrase. D The Cl atoms cause fewer temporary hydrogen bonds between sucralose and the active site of sucrase.

6 JPJC/JC2 H2 Biology/Prelim/2024 8 Cancer is believed to often arise from stem cells, rather than fully differenti ated cells. Which statements are consistent with this view? 1 DNA replication is necessary for mutations to occur, and stem cells are replicating their DNA whereas differentiated cells are for the most part not replicating their DNA. 2 Stem cells are actively dividing and express few differentiated functions, so they may have fewer changes to undergo than do fully differentiated cells in becoming cancer cells. 3 Since all stem cells are totipotent, tumours can easily arise from stem cel ls without further mutation. 4 Stem cells require certain genes for the maintenance of their stem cell function, and many such genes can also function as oncogenes. A 1, 2, 3 and 4 B 1, 2 and 4 only C 1 and 3 only D 2 only

7 JPJC/JC2 H2 Biology/Prelim/2024 [Turn over 9 The following steps describes the events taking place during the elongation of a polypeptide. 1 Free tRNA molecules bind to their corresponding amino acids at their specific anticodon and transport it to the ribosome. 2 A tRNA with a complementary anticodon binds to the A site bringing its specific amino acid along. 3 The initiator tRNA moves from the P to the E site on the ribosome wher e it initiates translation. 4 The amino acid carried by the tRNA at the P site is linked to the po lypeptide chain by a peptide bond. 5 tRNA carrying the peptide chain moves from the A site to the P site as the ribosome moves in the 5' → 3' direction along the mRNA molecule. Which steps contain information that is not correct? A 1, 3, 4 and 5 B 1, 3 and 4 only C 1 and 3 only D 2, 4 and 5 10 Which statements on viruses are not correct? 1 The HIV polyprotein is synthesised from a polycistronic mRNA template. 2 Influenza virus undergoes genetic drift as there is an accumulation of mutations in the haemagglutinin gene with time. 3 T4 phage is the agent involved in specialised transduction. 4 Replication cycles of both HIV and lambda phage have a latent phase. A 1, 2 and 3 B 1 and 2 only C 3 only D 4

8 JPJC/JC2 H2 Biology/Prelim/2024 11 How many statements about bacterial genetic transfer are correct? 1 In transformation, bacterial cells which possess competence factors can take up only plasmids from the surroundings. 2 Homologous recombination is always involved in bacterial genetic transfer. 3 After conjugation, the donor and recipient cells always contain the same genetic information. 4 Binary fission will not contribute to genetic variation in bacterial chromosomes. A 1 B 2 C 3 D 4 12 A regulatory protein binds to a site on an mRNA molecu