CJC 2023 JC2 Bio P3 (QP)

NAME: ___________________________________________ CLASS: _________ INDEX: __________ CATHOLIC JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION Higher 2 BIOLOGY 9744/03 Paper 3 Long Structured and Free-Response Questions 13 September 2023 2 Hours Candidates answer on the Question Paper. Additional Material: Writing Booklet. READ THESE INSTRUCTIONS FIRST Write your name (as per NRIC), class, and index number on all the work you hand in. Write in dark blue or black pen on both sides of the paper. [PILOT FRIXION ERASABLE PENS ARE NOT ALLOWED] You may use a soft pencil for any diagrams, graphs, or rough working. Do not use staples, paper clips, highlighters, glue, or correction fluid. Section A Answer all questions in the spaces provided on the Question Paper. Section B Answer any one question in this section. Write your answers in the writing booklet provided. The use of an approved scientific calculator is expected, where appropriate. You may lose marks if you do not show your working or if you do not use appropriate units. The number of marks is given in brackets [ ] at the end of each question or part question. This document consists of 15 printed pages and 1 blank page. [Turn over For Examiner’s Use Section A 50 1 2 3 Section B 25 4 or 5 Total 75

2 2023 Prelim/ 9744/ 03 Section A Answer all the questions in this section. 1 Endosymbiont is a cell which lives inside another cell with mutual benefit. The organelle in Fig. 1.1 is believed to have evolved from the early prokaryote that was engulfed by phagocytosis. The engulfed prokaryotic cell remained undigested as it contri buted new functionality t o the engulfing cell. Over generations, the engulfed prokaryotic cell lost some of its independent utility and became a supplemental organelle. Fig 1.1 (a) Explain how the organelle shown above supports the endosymbiotic theory. ……………………………………………………………………………………………………………...... ……………………………………………………………………………………………………………...... ……………………………………………………………………………………………………………...... ……………………………………………………………………………………………………………. [2] (b) Explain how the organelle is adapted to its function. ……………………………………………………………………………………………………………...... ……………………………………………………………………………………………………………...... ……………………………………………………………………………………………………………...... ……………………………………………………………………………………………………………...... ……………………………………………………………………………………………………………...... ……………………………………………………………………………………………………………. [3]

3 2023 Prelim/ 9744/ 03 Scientists use the DNA of the organelle shown in Fig. 1.1 for phylogenetic analysis. Analysis of DNA has been used extensively to study the evolutionary relationships across many species. (c) Explain the advantages of using the DNA of the organelle shown in Fig. 1.1 for phylogenetic analysis as compared to using nuclear DNA. ……………………………………………………………………………………………………………...... ……………………………………………………………………………………………………………...... ……………………………………………………………………………………………………………...... ……………………………………………………………………………………………………………...... ……………………………………………………………………………………………………………...... ……………………………………………………………………………………………………………. [3] The DNA of the organelle shown in Fig. 1.1 is more susceptible to oxidation than nuclear DNA, possibly because of its proximity to the electron transport chain in its inner membrane. As a result, the rate of mutation becomes much higher. (d) Suggest why the DNA of the organelle shown in Fig. 1.1 has a high mutation rate. ……………………………………………………………………………………………………………...... ……………………………………………………………………………………………………………. [1] Part of the sequence of the template DNA strand from 2 gene loci that code for different transport proteins in the organelle in Fig. 1.1 were shown in Fig. 1.2 below. In addition, Fig. 1.2 shows the corresponding sequences containing the mutation, mutation A and mutation B respectively. Wild-type sequence at gene locus 1 3’ – CTT AGA CTT ACT – 5’ Sequence containing mutation A 3’ – CTT AGT ACT TAC – 5’ Wild-type sequence at gene locus 2 3’ – CTC CTA AAA CCT – 5’ Sequence containing mutation B 3’ – CTC CCA AAA CCT – 5’ Fig. 1.2 (e) With reference to Fig. 1.2, state which mutation results in a frameshift. ……………………………………………………………………………………………………………. [1]

4 2023 Prelim/ 9744/ 03 Fig. 1.3 below shows the triplet codes that code for the different amino acids. Fig. 1.3 It was found that mutation A produced a fully functional transport protein, while mutation B led to the production of a non-functional transport protein. (f) With reference to Fig. 1.2 and Fig. 1.3, (i) suggest how mutation A could still lead to the production of a fully functional transport protein. Explain your answer. ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… …………………………………………………………………………………………………….. [3]

5 2023 Prelim/ 9744/ 03 (ii) suggest how mutation B led to the production of a non-functional transport protein. Explain your answer. ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… …………………………………………………………………………………………………….. [3] Different respiratory substrates are available to muscles to maintain the ATP levels required for muscle contraction. These include glucose and fatty acids from the blood as well as glycogen in the muscle. Table 1.1 shows the percentage contribution of each of these respiratory substrates to m uscle respiration in an athlete, during a 40 km long-distance run. Results are shown at four different times from the start of the run. Table 1.1 (g) With reference to Table 1.1., explain the change in percentage contribution of the different respiratory substrates to muscle respiration. ……………………………………………………………………………………………………………...... ……………………………………………………………………………………………………………...... ……………………………………………………………………………………………………………...... ……………………………………………………………………………………………………………...... ……………………………………………………………………………………………………………...... ……………………………………………………………………………………………………………. [3] Time / Minutes Percentage Contribution to Muscle Respiration Glucose from blood Fatty acids from blood Glycogen in muscle 60 67 17 26 120 46 22 32 180 16 30 54 240 10 62 28

6 2023 Prelim/ 9744/ 03 (h) Suggest why fatty acids can also be utiilised for cellular respiration. ……………………………………………………………………………………………………………...... ……………………………………………………………………………………………………………. [1] An in-vitro study showed that a complete oxidation of 1 molecule of glucose produces 2880 units of energy. It was found that the hydrolysis of 1 molecule of ATP generates 31 units of energy. (i) Based on the information above and your background knowledge, (i) calculate the percentage efficiency of energy production of anaerobic respiration in the cell as compared to the complete oxidation of glucose in-vitro. Show your working clearly. [2] (ii) calculate the percentage efficiency of energy production of aerobic respiration in the cell as compared to the complete oxidation of glucose in-vitro. Show your working clearly. [2] (iii) Suggest why the amount of energy generated by the aerobic respiration in the cell is different from the complete oxidation of