YTSS PURE BIO 3

NAME: ( ) CLASS: YISHUN TOWN SECONDARY SCHOOL PRELIMINARY EXAMINATION 2024 SEC 4 EXPRESS BIOLOGY (6093/1) DATE : 28 August 2024 DAY : Wednesday DURATION : 1 hr MARKS : 40 marks ADDITIONAL MATERIALS Multiple Choice Answer Sheet (OMS) READ THESE INSTRUCTIONS FIRST Write your name, class and register number in the spaces provided at the top of this page and on the OMS. There are forty questions. Answer all questions. For each question, there are four possible answers, A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the OMS answer sheet. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. You may use an approved calculator. This question paper consists of 17 printed pages

2 1 The diagrams below are organelles found inside cells. Which row identifies the typical distribution of these organelles? plants only animals and plants A 3 1, 2, 4 B 4 1, 2, 3 C 1, 4 2, 3 D 3, 4 1, 2 2 Which substances are not produced at the ribosomes? 1 amino acids 2 amylase 3 glycerol A 3 only B 1 and 2 C 1 and 3 D 2 and 3 3 The graph shows the concentrations of different ions inside and outside of an animal cell. Which process is directly responsible for the net movement of K + and Mg2+ ions into the animal cell? A absorption B active transport C diffusion D osmosis

3 4 The diagram shows a permeable tubing filled with salt solution in a test-tube of water. Which graph shows the changes in salt concentration inside and outside the tubing after 24 hours? 5 Two samples of food are tested. The results are shown in the table. sample results iodine test Benedict’s test biuret test X brown orange blue Y blue-black blue violet What do these results show? A Sample X contains reducing sugars and starch. B Sample X contains starch only. C Sample Y contains protein and starch. D Sample Y contains protein only.

4 6 The table shows the percentage of carbon, hydrogen, nitrogen and oxygen atoms in three molecules, X, Y and Z. molecule percentage of atoms / % carbon hydrogen nitrogen oxygen X 25.0 50.0 0.0 25.0 Y 28.5 42.7 8.0 20.8 Z 35.0 61.6 0.0 3.4 Which correctly identifies molecules X, Y and Z? X Y Z A fat protein glucose B glucose protein fat C protein glucose fat D protein fat glucose 7 In an enzymatic reaction, where is the active site located and what represents the lock and the key? active site lock key A on the enzyme substrate enzyme B on the enzyme enzyme substrate C on the substrate enzyme substrate D on the substrate substrate enzyme