YIJC 2023 [H2] Prelim.P4 (QP)

@YIJC 9744/04/PE/2022 [Turn over YISHUN INNOVA JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME CG INDEX NO. H2 BIOLOGY 9744/04 29 Aug 2023 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 25 2 12 3 18 Total 55 This document consists of 16 printed pages and 2 blank pages.

2 @YIJC 9744/04/PE/2023 [Turn over Answer all questions. 1 The enzyme amylase breaks down starch to form reducing sugars. It has been found that tea affects the activity of amylase. You will investigate the effect of different concentrations of tea extract on the breakdown of starch by amylase. You are provided with the materials shown in Table 1.1. Table 1.1 label contents hazard volume / cm3 E amylase solution harmful irritant 30 T1 100% tea extract none 20 S starch solution none 50 W distilled water none 150 iodine iodine solution irritant 20 If any solution comes into contact with your skin, wash off immediately with cold water. It is recommended that you wear suitable eye protection. You will need to carry out a serial dilution of the 100% tea extract, T1, to reduce the concentration by half between each successive dilution. You are required to make up a sufficient volume of each tea extract so that, once the serial dilution has been completed, there is a volume of at least 5.0cm 3 for each concentration prepared. (a) (i) Complete Table 1.2 to show you will make the concentration of the tea extract T1, T2, T3, T4 and T5. Table 1.2 Tea extract T1 T2 T3 T4 T5 percentage concentration of tea extract 100 percentage concentration of tea extract to be diluted volume of the tea extract to be diluted / cm3 volume of distilled water W / cm3 [3]

3 @YIJC 9744/04/PE/2023 [Turn over Read steps 1 – 12. Proceed as follows. 1 Prepare the concentrations of tea extract as shown in Table 1.2. 2 Label the test-tubes with the concentrations you have prepared in step 1. 3 Put 1 cm 3 of each concentration of tea extract into the appropriately labelled test-tube. 4 Put 1 cm3 of E into each of the labelled test-tubes. Shake gently to mix. 5 Using the beakers labelled hot water and cold water, set up and maintain a water -bath with water between 30°C and 40°C. 6 Put t