Dunman 6093 Prelims Paper 3 QP 2026

This document consists of 11 printed pages. DUNMAN SECONDARY SCHOOL CANDIDATE NAME CLASS INDEX NUMBER PRELIMINARY EXAMINATION 2026 SECONDARY 4 EXPRESS BIOLOGY 6093/03 Paper 3 Practical Test 20 August 2026 1 hour 50 minutes Candidates answer on the Question Paper Additional Materials: As listed in the Confidential Instructions. READ THESE INSTRUCTIONS FIRST Please check that your name, class and index number are correctly written. 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. 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. 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. Shift Laboratory For Examiner’s Use 1 2 Total

2 6093/03/Prelim/4Exp/2026 1 Amylase is an enzyme that catalyses the break-down of starch into reducing sugars. Amylase is produced by seeds during germination. You are provided with extract U, which is made from germinating seeds. You are going to estimate the concentration of amylase in seed extract U by comparing it to known concentrations of amylase. 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). You should use the gloves and eye protection provided while you are carrying out the practical work. Step 1 Label four small containers A, B, C, and D. Step 2 Use the syringes to add the volumes of 2% amylase and distilled water shown in Table 1.1 to each labelled beaker. Table 1.1 container volume of 2% amylase solution / cm3 volume of distilled water / cm3 final percentage concentration of amylase solution / % A 10.0 0.0 2.0 B 7.5 2.5 1.5 C 5.0 5.0 1.0 D 2.5 7.5 (a) (i) Complete Table 1.1 by calculating the final percentage concentration of amylase solution for container D. ............................................... % [1] Step 3 Label five test-tubes A, B, C, D and U. Step 4 Use a syringe to add 3 cm3 of starch suspension to each of the labelled test-tubes.

3 6093/03/Prelim/4Exp/2026 Step 5 Prepare a white tile by using a pipette to put drops of iodine solution in five columns labelled A, B, C, D and U, as shown in Fig. 1.1. There should be 8 drops of iodine solution in each column. Fig. 1.1 Step 6 Use a clean syringe to add 1 cm3 of amylase solution from container A to test-tube A and shake gently to mix. Step 7 Repeat step 6 using containers B, C, D and U and test-tubes B, C, D and U. Step 8 Start the stopwatch. Step 9 After one minute use a clean pipette to remove one drop of solution from test -tube A and add it to the first drop of iodine solution, A1, on the white tile. Observe any colour change. Step 10 Repeat step 9 using: • the contents of test-tube B and iodine solution drop B1 • the contents of test-tube C and iodine solution drop C1 • the contents of test-tube D and iodine solution drop D1 • the contents of test-tube U and iodine solution drop U1. Step 11 Repeat steps 9 and 10 after two minutes using iodine solution drop A2, B2, C2, D2 and U2. Step 12 Continue to test the contents of the test -tubes at one minute intervals until a drop of the mixtures in the test-tubes has been added to all eight rows of iodine solution drops on the white tile. time / minutes drop of iodine solution white tile A B C D U 1 2 3 4 5 6 7 8

4 6093/03/Prelim/4Exp/2026 Step 13 Observe the colour of each drop of iodine solution on the white tile and determine the time at which the starch in each test-tube was broken down. In your table in 1(a)(ii), record the time taken for the starch to be completely broken down. If starch was still present in row 8 record the time taken as >8. (ii) Prepare a table to record your results. [4] (iii) Explain how you decided when all of the starch had been broken down in step 13. …………………………………………………………………………………………………... ……………………………………………………………….……………………………….[1] (iv) Estimate the concentration of amylase in seed extract U using your results and record it in your table in 1(a)(ii). [1]

5 6093/03/Prelim/4Exp/2026 (v) Describe how you would test for the presence of reducing sugars. State the result for a positive test. method …..……………………………………………………………………………..……… …………………………………………………………………………………………………... …………………………………………………………………………………………………... positive test result …………………………………………………………………………..[3] (b) Seeds contain starch as a store of energy. Amylase in the seeds catalyses the break -down of the stored starch into reducing sugars. Seeds use the reducing sugars to provide some of the energy required for germination. Plan an investigation to find out how temperature affects the activity of amylase in germinating seeds. ………………………………………………………………………………………………………….. ………………………………………………………………………………………………………….. ………………………………………………………………………………………………………….. ………………………………………………………………………………………………………….. ………………………………………………………………………………………………………….. ………………………………………………………………………………………………………….. ………………………………………………………………………………………………………….. ………………………………………………………………………………………………………….. ………………………………………………………………………………………………………….. ………………………………………………………………………………………………………….. ………………………………………………………………………………………………………….. ………………………………………………………………………………………………………..[6]

6 6093/03/Prelim/4Exp/2026 (c) A scientist investigated how the activity of amylase in a seed changed as it germinated. She measured the activity of amylase in a germinating seed over a period of 18 days. The results are shown in Table 1.2. Table 1.2 time / days activity of amylase / arbitrary units 0 0 4 0 8 40 12 240 16 240 20 120 24 65 (i) Plot a line graph of the data in Table 1.2. [4]

7 6093/03/Prelim/4Exp/2026 (ii) Describe the pattern shown by the data in your graph. …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... ……………………………………………………………….……………………………….[2] (d) (i) The data in Table 1.2 did not enable the scientist to determine precisely when the amylase was most active. Explain why. …………………………………………………………………………………………………... ……………………………………………………………….……………………………….[1] (ii) Suggest what further data is needed to be able to determine exactly when amylase was most active. …………………………………………………………………………………………………... ……………………………………………………………….……………………………….[1] [Total: 24]

8 6093/03/Prelim/4Exp/2026 2 (a) Fig. 2.1 is a photograph of a cross‑section of a persimmon fruit. Fig. 2.1 (i) Draw a large diagram of the persimmon fruit shown in Fig. 2.1. [4] P Q magnification ×2.2

9 6093/03/Prelim/4Exp/2026 (ii) Line PQ on Fig. 2.1 represents the diameter of the persimmon fruit. Measure the length of line PQ on Fig. 2.1. length of PQ ............................................... mm [1] (iii) Calculate the actual diameter of the persimmon fruit using the formula and your measurement. Show your working clearly. Give your answer to t