HCI 2024 Prelim H2 Bio P4 Qn

© Hwa Chong Institution 2024 9744 H2 Biology / JC2 Preliminary Examinations / Paper 4 HWA CHONG INSTITUTION JC2 Preliminary Examinations Higher 2 CANDIDATE NAME CT GROUP 23S7__ CENTRE NUMBER INDEX NUMBER BIOLOGY Paper 4 Practical Candidates answer on the Question Paper. Additional Materials: As listed in the Confidential Instructions. 9744/04 26 August 2024 2 hours 30 minutes INSTRUCTIONS TO CANDIDATES There are two question booklets ( I and II) to this paper. Write your name, CT group, Centre number and index number in the spaces provided at the top of this cover page and on the lines provided at the top of the cover page of Booklet II. Give details of the practical shift and laboratory, where appropriate, in the boxes provided. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Answer all questions in the spaces provided on the question paper. INFORMATION FOR CANDIDATES 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. You are reminded of the need for good English and clear presentation in your answers. This document consists of 16 printed pages. Shift Laboratory For Examiners' Use 1 / 30 2 / 25 Total / 55

2 © Hwa Chong Institution 2024 9744 H2 Biology / JC2 Preliminary Examinations / Paper 4 QUESTION 1 A group of students investigated the growth of different varieties of yeast. The students learnt that the rate of respiration can be used as a measure of the growth of a yeast culture, which depends on a variety of factors. One such factor is the activity of enzymes that are responsible for hydrolysing sucrose into reducing sugars to be used as respiratory substrate. You will investigate the activity of the enzymes in yeast cells, which will be immobili sed in sodium alginate beads. You are provided with the materials shown in Table 1.1. Table 1.1 labelled contents hazard volume / cm3 Y yeast cell suspension none 40 A sodium alginate solution harmful irritant 20 C calcium chloride solution harmful irritant 30 S sucrose solution none 100 B Benedict’s solution harmful irritant 30 If any solution comes into contact with your skin, wash off immediately under cold water. It is recommended that you wear suitable eye protection. You will investigate the activity of yeast enzymes by using different numbers of beads of immobilised yeast cells in sucrose solution, S. Carry out steps 1 – 9 to immobilise the yeast cells in sodium alginate beads. 1 Put 10 cm3 of A into a beaker. 2 Stir the yeast cell suspension Y with a glass rod. 3 Put 10 cm3 of Y into the beaker containing A and mix well. Do not