2024 MFSS 4Exp 5088 Prelim ScBio P4

1 [Turn over] Name Reg. No Class MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL MAYFLOWER SECONDARY SCHOOL 4EX SCIENCE (CHEMISTRY, BIOLOGY) 5088/04 Biology Component Paper 4 [65 Marks] PRELIMINARY EXAMINATION Additional Materials: Approved calculator Aug 2024 1 hour 15 minutes Instruction to Candidates Write your name, class and index number on all the work you hand in. Write in dark blue or black pen. You may use a soft pencil for any diagrams, graphs or rough working. FOR EXAMINER’S USE Paper Marks Paper 1 (MCQ) / 20 Paper 3 A / 55 B 8 / 9 / 10 Paper 5 / 15 Total / 100 Do not use staples, paper clips, highlighters, glue or correction fluid. The use of an approved scientific calculator is expected, where appropriate. This paper consists of two sections. Section A will carry 55 marks and will contain a number of compulsory structured questions. The last question will carry 10 marks. Section B will carry 10 marks and will contain two questions. Candidates must answer only one out of these two questions. 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 question paper consists of 16 printed pages. Setter: Mrs Marie Huang Vetter: Mrs Vija 4EX

2 Section A (55 marks) Answer all the questions in the spaces provided. 1 Some students investigated the effect of immersing red blood cells in different concentrations of salt solutions. They measured the diameters of samples of red blood cells and calculated the mean. They then immersed the red blood cell samples in different concentrations of salt solutions. After two minutes they measured and calculated the mean of the samples again. Table 1.1 shows the results. Table 1.1 percentage concentration of the salt solution / % mean initial diameter of the red blood cells /µm mean diameter of the red blood cells after two minutes / µm 0.4 7.5 Cells burst 0.8 7.5 8.2 0.9 7.5 7.5 1.8 7.5 6.0 (a) Calculate the percentage increase in the mean diameter of red blood cells that were immersed in the 0.8% salt solution. Give your answer to three significant figures. Answer………………….. % [2] (b) (i) Explain the results for the red blood cells that were immersed in 1.8% salt solution. …………………………………………………………………………………….. …………………………………………………………………………………….. …………………………………………………………………………………….. …………………………………………………………………………………….. [2] (ii) State why there was no change in the mean diameter of the red blood cells immersed in 0.9% salt solution. ……………………………………………………………………………………. ……………………………………………………………………………………. [Total = 5] [1]

3 [Turn over] 2 An experiment was conducted to investigate the action of enzyme amylase in solutions of different pH. Six test-tubes were set up where each test -tube was filled with buffer solutions of pH 4, 5, 6, 7, 8 and 9. 2 cm 3 of amylase and 8 cm 3 of starch were added into each test - tube in sequence. The first set-up is shown in Fig 2.1. 0.5 cm3 of the mixture in the test-tube was taken out every 30 seconds and tested for starch, until it gave a negative test. The time taken for all the starch to be digested was recorded in Table 2.2. Table 2.2 pH time taken for starch to be digested / minutes 4 10.0 5 7.5 6 5.0 7 6.0 8 10.5 9 16.5 (a) Plot these results on the grid. [3] pH Time taken to digest starch/ minutes

4 (b) Describe the test for starch and the expected results. ……………………………………………………………………………………………. ……………………………………………………………………………………………. ……………………………………………………………………………………………. ……………………………………………………………………………………………. [2] (c) From your graph, state the optimum pH for amylase action. optimum pH = ………………………… [1] (d) Describe briefly how starch is digested in the alimentary canal. …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… ……………………………………………………………………………………………. [2] [Total = 8] 3 A pulse oximeter is a device that fits on the end of a finger. It measures the heart rate (pulse rate) in beats per minute and the percentage of oxygen in the blood (%SpO2) Fig 3.1 shows a photograph of a pulse oximeter. Fig 3.1 John, a non -smoker, used a pulse oximeter to investigate the effect of exercise on heart rate and the percentage of oxygen in the blood. He recorded readings from the pulse oximeter before exercise (0, 1, 2 minutes). He then exercised for 5 minutes. At the end of 5 minutes, he recorded four more readings at 7, 8, 9 and 10 minutes. The results are shown in Table 3.1

5 [Turn over] Table 3.1 time / minutes heart rate / beats per minute percentage blood oxygen 0 66 98 1 65 99 2 66 99 7 110 96 8 96 97 9 85 98 10 68 98 (a) (i) Using the above data in Table 3.1, describe and explain any changes in John’s heart rate during the investigation. …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… [2] (ii) Using the above data in Table 3.1, describe and explain any changes in the percentage of oxygen in his blood during the investigation. …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… [2] (iii) John thought the way he was breathing could have affected the percentage of oxygen in his blood during exercise. What could he do to increase his percentage of oxygen in his blood? …………………………………………………………………………………… [1] (b) A man is a heavy smoker and is suffering from emphysema. Suggest how this person’s normal pulse rate and percentage of oxygen in his blood may vary from those of John in (a). …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… [Total=7 marks] [2]

6 4 Fig 4.1 shows the internal structure of the leaf. Fig 4.1 (a) (i) Label X and name the cell(s) where maximum photosynthesis takes place. [1] (ii) Label Y and name the cell(s) which transport water to the cells. [1] The figure shows three plants A, B and C, growing in pots. Each plant was treat