H2 Bio 2024 YIJC Prelim Paper 4 (QP)

1 @YIJC 9744/04/PE/2024 [Turn over YISHUN INNOVA JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME CG INDEX NO. H2 BIOLOGY 9744/04 22 Aug 2024 2 hours 30 minutes READ THESE INSTRUCTIONS FIRST Write your name and class in the spaces at the top of this page. Write in dark blue or black pen only. You may use a soft pencil for any diagrams or graphs. Do not use paper clips, highlighters, glue or correction fluid. Answer all questions in the spaces provided on the Question 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 not use appropriate units. The number of marks is given in brackets [ ] at the end of each question or part question. Shift Laboratory For Examiner’s Use 1 22 2 16 3 17 Total 55 This document consists of 20 printed pages.

2 @YIJC 9744/04/PE/2024 [Turn over 1 Plant tissues contain the enzyme catalase which catalyses the breakdown of hydrogen peroxide into oxygen gas and water. Ascorbic acid acts as an inhibitor of catalase. You will investigate the effect of changing ascorbic acid concentration on catalase activity. You are provided with the materials shown in Table 1.1. Table 1.1 If H or A comes into contact with your skin, wash off immediately under cold water. It is recommended that you wear suitable eye protection. You are also provided with five cylinders of potato tissue, labelled P. (a) You will need to carry out a serial dilution of the 1moldm–3 ascorbic acid, A, to reduce the concentration by a factor of ten between each successive dilution. You will need to prepare four concentrations of ascorbic acid in addition to the 1moldm–3 ascorbic acid solution, A. After the serial dilution is completed, you will need to have at least 9 cm3 of each concentration available to use.

3 @YIJC 9744/04/PE/2024 [Turn over (i) Complete Table. 1.2 to show how you will prepare your serial dilution. Table 1.2 shows the first two beakers you will use to make your serial dilution. You will need to complete three additional beakers. For each beaker, state: • the concentration of the ascorbic acid prepared • the concentration of the ascorbic acid transferred • the volume of ascorbic acid solution transferred • the volume of distilled water, W, added. Table 1.2 Concentration of ascorbic acid / moldm-3 Concentration of the ascorbic acid transferred / moldm-3 volume of ascorbic acid solution transferred / cm3 volume of distilled water, W, added / cm3 1.0 1.0 10.0 0.0 0.1 1.0 1.0 9.0 [3] Carry out step 1 to step 13. 1 Prepare the concentrations of ascorbic acid solution, as decided in (a)(i), in the beakers provided. 2 Label the test‐tubes with the ascorbic acid concentrations prepared in st