BEDOK SOUTH SECONDARY SCHOOL 2018 P4 QP

This document consists of 16 printed pages including this cover page. [Turn Over BEDOK SOUTH SECONDARY SCHOOL PRELIM INARY EXAMINATION 2018 4EXP CANDIDATE NAME CLASS REGIST ER NUMBER SCIENCE (BIOLOGY, CHEMISTRY) Paper 4 Biology Candidates answer on the Question Booklet. No Additional Materials are required 5078/04 2 August 2018 1 hour 15 minutes READ THESE INSTRUCTIONS FIRST Write you r class, index number and name on the work you hand in. Write in dark blue or black ink on both sides of the paper. Do not use staples, paper clips, highlighters, glue or correction fluid. Section A (45 marks) Answer all questions. Write your answers in the spaces provided on the question paper. Section B (20 marks) Answer any two questions. Write your answers on the question paper. The number of marks is given in brackets [ ] at the end of each question or part question. Setter: Ms. Denise Wong For Examiner’s Use Paper 1 P4 Section A P4 Section B Paper 5 Total 51

2 [Turn Over For Examiner’s Use SECTION A (45 marks) Answer all questions in the spaces provided. 1( a ) Fig. 1.1 shows part of the human digestive system. Fig. 1.1 (i) Table 1.1 lists some processes that occur in the human body. Comp lete the table by using letters from Fig. 1.1 to show where each process occurs. Table 1.1 process where process occurs protein is first digested bile is stored [2] (ii) A patient had surgery to remove part of organ C. Explain why the patient experienced weight loss in the weeks after the surgery. …………………………………………………………………………..……….............. …………………………………………………………………………..……….............. …………………………………………………………………………..……….............. …………………………………………………………………………..……….............. [ 2] 52

3 [Turn Over For Examiner’s Use (b) Fig. 1.2 shows the blood vessels associated with organs B and C. Fig. 1.2 (i) Identify blood vessels Y and Z. Y …………………………............................... Z …………………………............................... [2] (ii) Describe one structural difference between blood vessel Y and blood vessel Z. Explain how this difference helps blood vessel Y to perform its functions. …………………………………………………………………………..……….............. …………………………………………………………………………..……….............. …………………………………………………………………………..……….............. …………………………………………………………………………..……….............. [2] (iii) Explain why the concentration of glucose varies in blood vessel Z throughout the day while the concentration of glucose remains relatively c onstant in blood vessel X. …………………………………………………………………………..……….............. …………………………………………………………………………..……….............. …………………………………………………………………………..……….............. …………………………………………………………………………..……….............. …………………………………………………………………………..……….............. …………………………………………………………………………..……….............. [3] [Total: 11] 53

4 [Turn Over For Examiner’s Use 2 Rennin is an enzyme found in the human alimentary canal that curd les milk by converting soluble milk proteins into insoluble milk proteins. A n experiment was carried out to determine the effect of pH on the activity of re nnin at 30 ºC. Table 2.1 shows the results of the experiment. Table 2.1 pH time taken for milk to curdle / min rate of reaction / min-1 14 0.25 22 0.50 33 0.33 47 0.14 51 3 (a) (i) Calculate the rate of r eaction for pH 5. Show your working. rate of reaction = …………………………… min-1 [1] (ii) On the grid provided on the next page, plot a graph of rate of reaction against pH. Use the results in Table 2.1 and your answer to (ai). On your graph, use appropriate scales, label the axes and draw a line of best fit. [3] 54

5 [Turn Over For Examiner’s Use (iii) From your graph, state the pH where rennin is the most active. ……………………………………………………………………….............................. [1] (b) Describe t he test that can be done to conclusively prove that r ennin is protein in nature. State the results of the test. ………………………………………………………….……………...................................... ………………………………………………………….……………...................................... ………………………………………………………….……………...................................... ………………………………………………………….……………...................................... [ 2] 55

6 [Turn Over For Examiner’s Use (c) In another experiment, rennin wa s boiled and cooled down to 30 ºC before it was added to milk. Using your knowledge of the lock and key hypothesis, explain why the milk did not curdle. ………………………………………………………….……………...................................... ………………………………………………………….……………...................................... ………………………………………………………….……………...................................... ………………………………………………………….……………...................................... ………………………………………………………….……………...................................... ………………………………………………………….……………...................................... [3] [Total: 10] 3 Fig. 3.1 shows an experiment set up to investigate the change in the mass of plants A and B potted in damp soil over a period of time. Fig. 3.1 The loss in m ass was measured over a period of five days and the results are shown in Fig. 3.2. 56

7 [Turn Over For Examiner’s Use Fig. 3.2 (a) Define the process that caused the loss in mass observed in plant A. ………………………………………………………….……………...................................... ………………………………………………………….……………...................................... [1] (b) (i) On Fig. 3.2 , sketch a curve to show the results obtained for plant B.[ 1] (ii) Explain the curve drawn in (bi). ……………………………………………………………………….............................. ………………………………………………………………………................ .............. ……………………………………………………………………….............................. ……………………………………………………………………….............................. [2] (c) Explain why the rate of photosynthesis in plant B was found to decrease after 3 days. ………………………………………………………….……………...................................... ………………………………………………………….……………...................................... ………………………………………………………….……………...................................... ………………………………………………………….……………...................................... [2] [Total: 6] 57

8 [Turn Over For Examiner’s Use 4 Fig. 4 .1 shows the pressure changes in the aorta and chambers X and Y on the left side of the heart during one cardiac cycle in a healthy person. Fig. 4.1 (a) Identify chamber X. Explain how you arrived at your answer. ………………………………………………………….……………...................................... ………………………………………………………….……………...................................... ………………………………………………………….……………...................................... ………………………………………………………….……………...................................... [2] (b) Describe and explain how the volume of the chamber X changes with pressure in chamber X from time B to D. ………………………………………………………….……………...................................... ………………………………………………………….……………...................................... ………………………………………………………….……………...................................... ………………………………………………………….……………...................................... [2] 58

9 [Turn Over For Examiner’s Use (c) State the function of the valve that closes at D. ………………………………………………………….……………...................................... ………………………………………………………….……………...................................... [1] (d) It was observed that the increase in pressure in chamber X was greater in smokers than in healthy persons. By naming a component in cigarette smok e , e x p l a i n t h i s observation. component ………..………………………………….…………….............................. ........ explanation ………..………………………………….……………...................................... ………………………………………………………….……………...................................... [2] [Total: 7] 59

10 [Turn Over For Examiner’s Use 5 Colo ur blindness is controlled by a pair of alleles. The allele for normal vision (B) is dominant to the allele for colour blindness (b). Fig. 5.1