YIJC 2023 [H2] Prelim.P4 (ANS)

@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 30 Aug 2022 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 14 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 drinking 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 labelled contents hazard volume/cm3 E amylase solution harmful irritant 50 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 t he 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 50 25 12.5 6.25 percentage concentration of tea extract to be diluted 100 50 25 12.5 volume of the tea extract to be diluted / cm3 5.0 5.0 5.0 5.0 volume of distilled water W / cm3 5.0 5.0 5.0 5.0 1 100, 50, 25, 12.5, 6.25 (% concentration of tea extract ) and 100, 50, 25, 12.5 (% concentration of tea extract to be diluted); 2 At least 5.0 cm3 for volume of the tea extract to be diluted ; 3 Equal volume of distilled water W added to the volume of tea extract to be diluted and precision to be kept to 1 decimal point ; Penalised only once for incorrect precision for MP2 and MP3

3 @YIJC 9744/04/PE/2023 [Turn over [3] Read steps 1 – 12. Proceeds as follows. 1 Pr