QTSS Prelim 2024 Sec 4E Science (Biology) P4 [5087]

This document consists of 19 printed pages. Name: ………………………………………………….. ( ) Class: Sec 4 SG2 Queenstown Secondary School Preliminary Examination 2024 Secondary Four Express Science (Biology) 5087/04 27 August 2024 Time: 1045 – 1200 h Tuesday Duration: 1 hour 15 minutes Setter: Additional Materials: Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, class and index number on all the work you hand in. You may use an HB pencil for any diagrams, graphs, tables or rough working. Write in dark blue or black pen. Do not use staples, paper clips, glue or correction fluid. 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. Section A Answer all questions. Write your answers in the spaces provided on the question paper. Section B Answer one question. Write your answers in the spaces provided on the question paper. The number of marks is given in brackets [ ] at the end of each question or part question. Examiner’s Use Section A /55 Section B /10 Q10 Q11 TOTAL /65

2 Queenstown Secondary School [Turn over Section A Answer all the questions in the spaces provided. 1 Beetroot cells contain a purple pigment in their cytoplasm. In an experiment, 6 strips of similar size were cut from a beetroot and thoroughly washed with water until the water was clear. Two strips each were weighed and then put into 3 different test tubes A to C as shown in Fig. 1.1. The setups were then left for 30 minutes. (a) State and explain the change in mass of the beetroot strips in test -tube A at the end of the experiment. change in mass of beet root strips in A: …………..………...…………………… ……………………………….…………………………………....…………………… explanation: …….………………….…………………………...…………………… ……………………………….…………………………………....…………………… ……………………………….…………………………………....…………………… …………………….………………….…………………………...…………………… ……………………………….…………………………………....…………………… [3] Hot water (90oC) turned purple at end of experiment Fig. 1.1

3 Queenstown Secondary School [Turn over (b) (i) The liquid in test-tube C appears purple at the end of the experiment. State the reason for the change in the colour of the liquid in test-tube C. ………………….………………………………………...…………………… ………………..……………….…………………………………....…………. ………………….………………………………………...…………………… ………………..……………….…………………………………....…………. [1] (ii) Predict, with an explanation, the appearance of the liquid in test-tube B at the end of experiment. ………………….………………………………………...…………………… ………………..……………….…………………………………....…………. ………………….………………………………………...…………………… ………………..……………….…………………………………....…………. [2] [Total: 6]

4 Queenstown Secondary School [Turn over 2 An experiment was conducted to study the effect of temperature on the action of pepsin using albumen (egg white). Pepsin is a protease which digests protein present in the albumen. Table 2.1 below shows the contents of test tubes A, B, C and D as well as the respective temperatures. The data obtained is shown in Fig. 2.2 below. The volume and concentration of the substances were the same in all the test tubes. Table 2.1 test tube contents temperature /˚C A Albumen + pepsin 10 B Albumen + pepsin 20 C Albumen + pepsin 37 D Albumen + pepsin that has been boiled 37 (a) Explain the difference in results obtained for test tubes B and C. …………………….………………….…………………………...…………………… ……………………………….…………………………………....…………………… …………………….………………….…………………………...…………………… ……………………………….…………………………………....…………………… [2] D A B C Time (min) Quantity of albumen present in test-tube Fig. 2.2

5 Queenstown Secondary School [Turn over (b) Use the lock and key hypothesis to explain the effect of high temperature on the rate of digestion of albumen in test-tube D. …………………….………………….…………………………...…………………… ……………………………….…………………………………....…………………… …………………….………………….…………………………...…………………… ……………………………….…………………………………....…………………… …………………….………………….…………………………...…………………… ……………………………….…………………………………....…………………… …………………….………………….…………………………...…………………… …………………….………………….…………………………...…………………… ……………………………….…………………………………....…………………… …………………….………………….…………………………...…………………… [4] (c) (i) State a substance (other than albumen) that is present in test tube C after 10 minutes. ………………….………………………………………...…………………… [1] (ii) Give a reason for your answer in (c) (i). ………………….………………………………………...…………………… ………………..……………….…………………………………....…………. ………………….………………………………………...…………………… [1] [Total: 8]

6 Queenstown Secondary School [Turn over 3 Fig. 3.1 below shows a section through the human heart. (a) (i) One stage of the heart cycle is the contraction of the part labelled A. What is the effect of this contraction? ………………….………………………………………...…………………… ………………..……………….…………………………………....…………. [1] (ii) In some people, the flaps of the part labelled B do not fit together properly. This causes the heart to be less efficient in pumping oxygenated blood to the organs of the body. Suggest a reason for this. ………………….………………………………………...…………………… ………………..……………….…………………………………....…………. ………………….………………………………………...…………………… ………………..……………….…………………………………....…………. [2] B A C Fig. 3.1

7 Queenstown Secondary School [Turn over (iii) Explain why the part labelled C is generally thicker than the walls of the rest of the heart. ………………….………………………………………...…………………… ………………..……………….…………………………………....…………. ………………..……………….…………………………………....…………. [1] (b) ( b ) Fig. 3.2 shows a small part of the blood supply to the walls of the heart. Describe one difference between blood that travels through the coronary artery and the coronary vein. …………………….………………….…………………………...…………………… ……………………………….…………………………………....…………………… …………………….………………….…………………………...…………………… ……………………………….…………………………………....…………………… [1] [Total: 5] Fig. 3.2 Branch of a coronary vein Branch of a coronary artery Cells of cardiac muscle

8 Queenstown Secondary School [Turn over 4 Sammy completed his 2.4 km run for his NAPFA test in 10 minutes and then rested for another 10 minutes. Fig. 4.1 shows the changes in concentration of lactic acid and muscle glucose of the student taken at different time intervals. 0 10 20 Time/min Fig. 4.1 (a) Define anaerobic respiration. …………………….………………….…………………………...…………………… ……………………………….…………………………………....…………………… …………………….………………….…………………………...…………………… [1] (b) Describe and explain the trend in glucose and lactic acid concentration in Sammy’s muscle during the 2.4 km run. …………………….………………….…………………………...…………………… ……………………………….…………………………………....…………………… …………………….………………….…………………………...…………………… …………………….………………….…………………………...…………………… ……………………………….…………………………………....…………………… …………………….………………….…………………………...…………………… [3] Concentration of substances in blood - - - glucose ____ lactic acid 0 10 20

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