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Unformatted text preview: This question paper consists of 4 printed pages, 3 blank pages and a Report Form. SB (SC) S09595/1 © CIE 2001 [Turn over CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certificate of Education Advanced Subsidiary Level BIOLOGY 8700/3 PAPER 3 Practical Test OCTOBER/NOVEMBER SESSION 2001 1 hour 15 minutes Candidates answer on the question paper. Additional materials: As listed in Instructions to Supervisors TIME 1 hour 15 minutes INSTRUCTIONS TO CANDIDATES Write your name, Centre number and candidate number in the spaces at the top of this page. Answer both questions. Write your answers in the spaces provided on the question paper. INFORMATION FOR CANDIDATES The intended number of marks is given in brackets [ ] at the end of each question or part question. You are advised to spend 55 minutes on Question 1 and 20 minutes on Question 2. Candidate Centre Number Number Candidate Name FOR EXAMINER’S USE TOTAL 2 1 2 8700/3/O/N/01 Question 1 [55 minutes] You are required to investigate the effect of temperature on the enzyme urease. Urease catalyses the following reaction. urea + water → ammonium carbonate Proceed as follows: Prepare two tins or beakers to act as water-baths. The temperature of the water in one should be about 50 °C, in the other, the water should boil. Label three test-tubes A , B and C respectively. Add one tablet of urease to tube A and place the bottom of the tube on the bench on a pad of paper or cloth. Using a glass rod, very gently crush the tablet into a powder, taking care not to break the bottom of the test-tube. Repeat this procedure for tubes B and C . To each of the three tubes, add 3 cm 3 of distilled water and stir to dissolve. Place tube A in the water-bath at 50 °C, tube B in the boiling water and tube C in a test-tube rack at room temperature. After five minutes , remove tubes A and B from the water-baths and cool them under a running tap. Measure out 10 cm 3 of urea solution into each of three further test-tubes....
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