TMJC 2023 H2 P4 QP

CANDIDATE NAME CIVICS GROUP _____________________________________________________________________________ H2 BIOLOGY 9744/04 Paper 4 Practical 24 August 2023 2 hours 30 minutes Candidates answer on the Question Paper. _____________________________________________________________________________ READ THESE INSTRUCTIONS FIRST Do not open this booklet until you are told to do so. Write your name, civics group and index number on all the work you hand in. 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 and graphs. Do not use staples, paper clips, glue or correction fluid/tape. Answer all questions in the spaces provided on the Question Paper. The use of 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. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. This document consists of 20 printed pages and 2 blank pages. Shift Laboratory For examiner’s Use 1 / 17 2 / 16 3 / 22 Total / 55 TAMPINES MERIDIAN JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION

2 Tampines Meridian Junior College 2023 JC2 Preliminary Examination H2 Biology Question 1 You should read throug h the whole of this question carefully and then plan your use of time to make sure that you finish all that you would like to do. Yeast cells are able to respire both aerobically and anaerobically using glucose as a substrate. You are required to investigate the effect of temperature on the rate of respiration of yeast using a respirometer. A simple respirometer can be made by attaching a length of plastic tubing to a 10 cm 3 syringe, using a short section of rubber tubing. The respirometer may be supported with a retort stand and clamp. Fig. 1.1 shows a simple respirometer containing a yeast suspension. Fig. 1.1

3 Tampines Meridian Junior College 2023 JC2 Preliminary Examination H2 Biology In order to introduce the yeast suspension into the simple respirometers, the following steps are used: • Remove a sample of the yeast suspension in 20% glucose solution and place it into a boiling tube. • Make sure that the plunger is pushed fully into the barrel of the syringe. • Insert the plastic tubing into the yeast suspension in a boiling tube. • Withdraw the plunger until the yeast suspension reaches the 5 cm 3 mark on the syringe. • Lift the respirometer so that the glass tubing comes out of the yeast suspension. • Keep the apparatus vertical. Slowly withdraw the plunger so that the yeast suspension rises up the plastic tubing until the suspension is near to the top of the plastic tubing (See Fig. 1.1). • Mark the start position of the meniscus of the yeast suspension. Consider a strategy to allow you to investigate the effect of temperature on the rate of respiration of yeast, making use of the apparatus provided. You will need to decide on a suitable range of temperature for this investigation. You are provided with: • simple respirometers • a suspension of yeast cells in a 20% glucose solution that has been maintained at 35°C for at least 15 minutes before the start of the examination • water at 30°C • water at 40°C • crushed ice • hot water at 70°C • a thermometer • a stopwatch • a retort stand. Determine the rate of respiration of yeast by measuring the movement of the meniscus down the plastic tubing.

4 Tampines Meridian Junior College 2023 JC2 Preliminary Examination H2 Biology (a) Describe how you will use the apparatus and materials provided to determine the effect of temperature on the rate of respiration. [10] Your plan should: • identify the independent and dependent variables. Identify the variables you will need to control. • include a control. • have a clear and helpful structure such that the method you use is able to be repeated by anyone reading it, including scientific reasoning behind procedure. • use the correct technical and scientific terms. • include reference to safety measures t o minimise any risks associated with proposed experiment. There is no need to describe how to set up respirometer in your methods (It has been described on page 3). ………………………………………………………………………………………………………………... ………………………………………………………………………………………………………………... ………………………………………………………………………………………………………………... ………………………………………………………………………………………………………………... ………………………………………………………………………………………………………………... ………………………………………………………………………………………………………………... ………………………………………………………………………………………………………………... ………………………………………………………………………………………………………………... ………………………………………………………………………………………………………………... ………………………………………………………………………………………………………………... ………………………………………………………………………………………………………………... ………………………………………………………………………………………………………………... ………………………………………………………………………………………………………………... ………………………………………………………………………………………………………………...

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