2025 NYJC H2 Bio 9744 P3 MS

NANYANG JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME ANSWER CLASS BIOLOGY 9744/03 Paper 3 Long Structured and Free-response Questions 19 September 2025 Additional Materials: Insert, Answer booklet 2 hours READ THESE INSTRUCTIONS FIRST Write your name and CT on all the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. 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 on the separate Answer Paper. 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 no use appropriate units. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use Section A 1 2 3 Section B Total This document consists of 16 printed pages. [Turn over H

2 9744 / H2 Biology / 03 Section A Answer all the questions in this section. 1 Different types of respiratory substrate can have different energy values and therefore release different quantities of energy when they are respired. (a) Complete Table 1.1 to show the energy value of each of the three main types of respiratory substrate. Use one tick (√ ) to identify which of the two possible energy values is correct for each respiratory substrate. Table 1.1 [1] (b) Organic acids such as malic acid can also act as respiratory substrates. When respired aerobically, their RQ values may be different to the RQ values of the main respiratory substrates. (i) Calculate how many molecules of oxygen are taken in when one molecule of malic acid is respired aerobically. number of molecules of oxygen = ........................ three................................. [1]

3 9744 / H2 Biology / 03 (ii) Calculate the RQ for malic acid. Give your answer to two decimal places. RQ = ....................... 1.33.................................. [1] (c) Determining the respiratory quotient (RQ) of an organism can be used to indicate the main type of respiratory substrate that is being metabolised in respiration. This is because the different types of respiratory substrate have different RQ values. Table 1.2 shows typical RQ values for carbohydrate, lipid and protein. (i) State the name of the laboratory apparatus that can be used to determine the RQ value of organisms such as blowfly larvae. respirometer [1] (ii) When determining RQ values using the laboratory apparatus stated in (b)(i), chemicals such as soda lime or potassium hydroxide solution are used. State the reason for using chemicals such as soda