VJC 2023 H2 9744_P4 QP

VICTORIA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION 2023 HIGHER 2 NAME : ………………………………………………….………………. CT CLASS : ………………..……… BIOLOGY 9744 Practical 30/08/2023 2 hours 30 minutes READ THESE INSTRUCTIONS FIRST 1. Write your name, CT class shift number and laboratory in the spaces provided. 2. Answer all questions in the spaces provided on the Question Paper. The number of marks is given in brackets [ ] at the end of each question. 3. Write in dark blue or black pen. You may use an HB pencil for diagrams, tables and graphs. 4. You should spend the first 5 minutes carefully reading the whole paper before starting to answer any question. 5. This paper consists of 3 questions. Students with the microscope and slide must begin with question 3. You may continue with question 1 or 2 after you have completed question 3. 7. 1 hr 15 min after the start of the exam, students with microscope will need to pass the instrument to their bench partners. Shift For examiner’s use 1 /20 Laboratory 2 /17 3 /18 Total /55 This document consists of 19 printed pages and 1 blank page. [Turn over]

2 Answer all questions. 1 Yeast cells contain enzymes that catalyse metabolic reactions. Some of these reactions release carbon dioxide. You will investigate the release of carbon dioxide from a mixture of yeast and carbohydrate. The mixture is put into dialysis (Visking) tubing. The dialysis tubing acts as a partially permeable membrane, allowing the carbon dioxide to diffuse out of the dialysis tubing. You are provided with the materials shown in Table 1.1. Table 1.1 labelled contents hazard volume / cm 3 Y 1g dried yeast none - G 10.0% warm glucose solution none 20 W distilled water none 50 B bromothymol blue indicator solution harmful 10 D 20 cm length of dialysis tubing in a beaker of distilled water none – If any solution comes into contact with your skin, wash off immediately under cold water. It is recommended that you wear suitable eye protection. To test for the release of carbon dioxide, a sample of the water surrounding the dialysis tubing is added to drops of an indicator, B. Fig. 1.1 shows the effect of increasing concentration of carbon dioxide on the colour of B. Yellow is the end-point. BLUE blue-green GREEN green-yellow YELLOW Fig. 1.1 no carbon dioxide highest concentration of carbon dioxide

3 Carry out steps 1 to 21. 1 Using hot water provided and tap water, adjust the water in the beaker labelled water-bath to 45 °C. You will not need to maintain this temperature. 2 Put 15 cm3 of G into the boiling tube labelled Y which contains 1g dri