ACSI P3 - Y4 Exp Bio Prelim 2024

CANDIDATE NAME CENTRE NUMBER S 2 0 3 1 INDEX NUMBER BIOLOGY 6093/03 Paper 3 Practical Test Candidates answer on the Question Paper. 31 July 2024, Wednesday 1 hour 50 minutes READ THESE INSTRUCTIONS FIRST Write your name and index number on all the work you hand in. Give details of the practical shift and laboratory in the boxes provided. Write in dark blue or black pen. You may use a HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue, correction fluid or highlighters. 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 2 3 Total /40 This document consists of 13 printed pages, including this cover page. Anglo-Chinese School (Independent) PRELIMINARY EXAMINATION YEAR FOUR EXPRESS

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3 6093/03/Y4Exp/Prelim/Jul2024 [Turn Over 1 Catalase is an enzyme found in living cells. It catalyses the breakdown of hydrogen peroxide to form water and oxygen. You are going to investigate the effect of catalase concentration on the rate of oxygen production. You have been provided with a celery extract which contains catalase. Read all the instructions but do not carry them out until you have drawn a table for your results in the space provided in 1(a)(ii). If any solution comes into contact with your skin, wash off immediately under cold water. You are advised to wear gloves and eye protection throughout the investigation. Step 1 Label five test-tubes A, B, C, D and E. Put the test-tubes into the test-tube rack. Step 2 Use a measuring cylinder to transfer 10 cm3 of celery extract into test-tube A. Step 3 Use the measuring cylinder to transfer 5 cm3 of celery extract from test -tube A to test-tube B. Use the measuring cylinder to add 5 cm3 of distilled water to test -tube B. Place a stopper in test-tube B and shake it to mix. Step 4 Remove the stopper. Use the measuring cylinder to transfer 5 cm3 of the liquid in test-tube B to test-tube C. Use the measuring cylinder to add 5 cm3 of distilled water to test -tube C. Place a stopper in test-tube C and shake it to mix. Step 5 Remove the stopper. Use the measuring cylinder to transfer 5 cm3 of the liquid in test-tube C to test-tube D. Use the measuring cylinder to add 5 cm3 of distilled water to test -tube D. Place a stopper in test-tube D and shake it to mix. Step 6 Remove the stopper. Use the measuring cylinder to transfer 5 cm3 of the liquid in test-tube D to test-tube E. Use the measuring cylinder to add 5 cm3 of distilled water to test -tube E. Place a stopper in test-tube E and shake it to mix. Remove the stopper.

4 6093/03/Y4Exp/Prelim/Jul2024 (a)(i) Table 1.1 shows concentration of the celery extract in test-tubes A to E. Table 1.1 test-tube percentage concentration of celery extract / % A 100.00 B 50.00 C D 12.50 E 6.25 Complete Table 1.1 by calculating and writing in the percentage concentration of celery extract in test- tube C. [1] Step 7 Use the ruler to measure 2 cm from the top (open end) of the long test-tube. Mark this distance by drawing a line on the test-tube with the marker pen. Step 8 Pour approximately 2 cm3 of the celery extract from test-tube A into the small plastic container, as shown in Fig. 1.1. Fig. 1.1 Step 9 Use the forceps to place one paper disc into the celery extract in the small plastic container. Leave it to be immersed for about 20 seconds. Step 10 Use the forceps to remove the paper disc from the small plastic container. Place the paper disc into the long test-tube you prepared in step 7 and push it to the bottom of the test-tube with the glass rod.

5 6093/03/Y4Exp/Prelim/Jul2024 [Turn Over Step 11 Carefully pour hydrogen peroxide solution into the long test-tube until it reaches the line you marked on the test -tube in step 7. Immediately start the stop watch and observe the paper disc rising. Record the time taken , in seconds, for the paper disc to reach the surface of the hydrogen peroxide solution, in your table in 1(a)(ii). If the paper disc has not reached the surface of the hydrogen peroxide solution after three minutes, stop the stopwatch and record the time as >180 in your table. Step 12 Pour the hydrogen peroxide solution and paper disc into the beaker labelled ‘waste’. Step 13 Use the forceps to place another paper disc into the celery extract in the small plastic container. Leave it to be immersed for about 20 seconds. Step 14 Use the forceps to remove the paper disc from the small plastic container. Place this paper disc into the long test-tube and push it to the bottom of the test-tube with the glass rod. Step 15 Pour hydrogen peroxide solution into the long test-tube until it reaches the line you marked. Immediately start the stop watch and record the time taken for the second paper disc to reach the surface of the hydrogen peroxide solution. Step 16 Calculate the mean time taken, to the nearest whole number, for the paper discs to reach the surface and include the answer in your table in 1(a)(ii). Step 17 Empty the contents of the small plastic container into the ‘waste’ beaker. Rinse the small plastic container and w ipe it dry with a paper towel. Rinse the long test -tube and shake it dry. Step 18 Do steps 8 to 16 for the remaining concentrations of celery extract in test-tubes B, C, D and E. (ii) Present all your results in an appropriate table in the space provided below. [4]

6 6093/03/Y4Exp/Prelim/Jul2024 (b)(i) Identify the independent variable and the dependent variable in this investigation. independent variable ..…..……………………………………………………………………………...……… dependent variable ..…..…………..…………………………………………………………………………… [1] (ii) State a conclusion for this investigation. ……………………………………………………………………………………………………………………. ……………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………….[1] (iii) Suggest a suitable control for this investigation and explain why this control would be used. control …………………….……………………………………………………………………...……………… ……………………………………………………………………………………………………………………. explanation ………...……………………………………………………………………………………...……. ……………………………………………………………………………………………….…………………… ………………………………………………………………………………………………………………….[2] (c)(i) The oxygen gas produced by the reaction forms bubbles on the paper disc which cause the disc to rise to the top of the hydrogen peroxide solution. The time taken for the disc to rise can be used to calculate the rate of the reaction. Explain how you could calculate the rate at which the disc rises. ……………………………………………………………………………………………………………………. ……………………………………………………………………………………………………………………. ……………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………….[2] (ii) State one significant source of error in this investigation and its effect on the results. source of error ……………….…………………………………………………………………………………. ……………………………………………………………………………………………………………………. effect on results ………………………………………………………………………………………………… ………………………………………………………………………………………………………………….[2]

7 6093/03/Y4Exp/Prelim/Jul2024 [Turn Over (d) Sodium chloride affects th