2024 ADSS Prelim P2

This question paper consists of 18 printed pages including this cover page. ADMIRALTY SECONDARY SCHOOL SUBJECT : Biology CODE/PAPER : 6093/2 LEVEL/STREAM : Secondary 4 Express DATE : 22 August 2024 TIME : 0800h – 0945h DURATION : 1 hour 45 minutes READ THESE INSTRUCTIONS FIRST Write your name, class and register number on all the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams, graphs, tables or rough working. Do not use staples, paper clips, glue or correction fluid. Section A Answer all questions. Write your answers in the spaces provided. Section B Answer one question. Write your answers in the spaces provided. The use of an approved scientific calculator is expected, where appropriate. The number of marks is given in brackets [ ] at the end of each question or part question. DO NOT TURN OVER THIS PAPER UNTIL YOU ARE TOLD TO DO SO. PRELIMINARY EXAMINATION 2024 For Examiner’s Use Section A / 70 Section B / 10 Total / 80 NAME: NO: CLASS:

2 Section A Answer all questions. 1 An experiment was set up to investigate the effect of different sodium chloride concentrations on the volume of animal cells. The final volume of the animal cells was compared with the original volume of animal cells and the results are shown in Fig. 1.1 Fig. 1.1 (a) With reference to Fig. 1.1, state the concentration of sodium chloride solution which has the same water potential inside the cells. Explain your answer. ………………………………………………………………………………….. ………………………………………………………………………………….. ………………………………………………………………………………….. [2] concentration of sodium chloride solution (mmol/dm3) ratio of final volume of cells to original volume of cells 0 10 20 30 40 50 60 70 80 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2

3 (b) Describe and explain the appearance of the animal cells placed in a concentration of sodium chloride solution of 40 mmol/dm3. …………………………………………………………………………………. …………………………………………………………………………………. …………………………………………………………………………………. [2] (c) (i) Predict an observation when these animal cells are placed in a concentration of sodium chloride solution less than 10 mmol/dm3. ……………………………………………………………………………. [1] (ii) Explain your answer in (c)(i). …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… [2]

4 2 In an experiment, four starch agar plates were prepared. Plates 1, 2 and 3 were treated with a filter paper disc soaked with liquid Y at different pH values. In plate 4, liquid Y was boiled and cooled before being placed on the agar starch as shown in Fig. 2.1. Fig. 2.1 The experiment set-ups were left for 30 minutes at 40 °C bef