Name : ( ) 4551/3 SMJK PEREMPUAN CHINA PULAU PINANG TRIAL EXAM 2012 BIOLOGY PAPER 3 1 HOUR 30 MINUTES DO NOT OPEN THIS BOOKLET UNTIL INSTRUCTED

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1 Name : ( ) 4551/3 Class : S5 BIOLOGY Paper 3 September ½ hours SMJK PEREMPUAN CHINA PULAU PINANG TRIAL EXAM 2012 BIOLOGY PAPER 3 1 HOUR 30 MINUTES DO NOT OPEN THIS BOOKLET UNTIL INSTRUCTED 1. This question booklet consists of two questions: Question 1 and Question 2 2. Answer all questions. Write your answers for Question 1 in the spaces provided in this question booklet. 3. Write your answers for Question 2 on the given lined paper. 4. The diagrams in the question are not drawn to scale unless stated. 5. If you wish to change your answer, cross out the wrong answer and write down your new answer. Question Total Marks Total 50 Marks obtained This booklet consists of 8 printed pages.

2 Answer all questions. (50 marks) 1. The movement of water molecules from a region of higher concentration to a region of lower concentration through a semi-permeable membrane is called osmosis. An experiment was carried out to study the movement of molecules across a semi-permeable membrane using a potato osmoscope. The steps of the experiment are as follows. Step 1 Step 2 Step 3 Step 4 : The skin of a large potato was peeled off using a scalpel and the potato was cut at one end to make a flat base. A deep cavity was made in the potato. : 2ml of 5% sucrose solution was poured into the cavity of the potato. : The potato was placed in a beaker containing 50ml of distilled water. : After 30 minutes, the volume of sucrose solution in the cavity was measured by using a measuring cylinder, and the volume was recorded in Table 1. The procedure of the experiment was repeated using different sucrose solution of different concentrations: 10%, 15% and 20%. The initial volume of sucrose solution used in the potato osmoscope is 2ml. Diagram 1 shows the potato osmoscope before and after the experiment. Diagram 1 2

3 Table 1 shows the results of the experiment. Concentration of sucrose solution (%) Volume of sucrose solution in the potato osmoscope Initial volume (ml) Final volume (ml) Difference in volume (ml) Table 1 a) Record the readings in the spaces provided in Table 1. 3

4 b) i) State two different observations made from Table 1. Observation 1: Observation 2: ii) State an inference from each of the observation in 1(b)(i). Inference from observation 1: Inference from observation 2: c) Complete Table 2 based on the experiment. Variable Method to handle the variable Manipulate variable: Responding variable: Constant variable: 4

5 d) State a hypothesis for this experiment. e) i) Construct a table and record all the data collected in this experiment. Your table should have the following aspects: - Concentration of the sucrose solution - Difference in volume of the sucrose solution - Percentage of difference in volume of the sucrose solution Percentage of difference in volume of the sucrose solution = Difference in volume of the sucrose solution X 100% Initial volume of the sucrose solution 5

6 ii) Use the graph paper provided to answer this question. By using data in 1(e)(i), draw a graph of the percentage of difference in volume of the sucrose solution against the percentage of concentration of the sucrose solution. f) Based on the graph in 1(e)(ii), explain the relationship between the percentage of difference in volume of the sucrose solution and the percentage of concentration of the sucrose solution. g) Based on the experiment, state an operational defination for osmosis. h) Another group of students carried out the same experiment using 2% sucrose solution. Predict the result of the experiment. Explain your prediction. 6

7 i) After immersing samples of plant cells in solutions with different type of solute concentration, Sarah discovered that the sample plant cells do not change its size and shape in 0.15M sodium chloride solution or 0.5M sucrose solution respectively. Below are the list of solutions used by Sarah in her experiment, classify the solutions according to the type of solute concentration as compared to the cell sap of the plant cell. Distilled water 0.5M sucrose solution 1.0M sucrose solution 0.15M sodium chloride solution 1.0M sodium chloride solution 0.15M sucrose solution Type of solute concentration Solution Hypertonic Hypotonic Isotonic 7

8 2. Adam is suffering from scurvy. His doctor advises him to take more citrus fruit juices such as, orange juice, pineapple juice and lime juice to improve his condition. Based on the above information, design a laboratory experiment to compare the ascorbic acid (Vitamin C) content in orange juice, pineapple juice and lime juice. The planning of your experiment must include the following aspects: Aims of investigation Problem statement Hypothesis Variables List of apparatus and materials Technique used Experimental procedure Presentation of data Conclusion (17 marks) END OF QUESTION PAPER Prepared by; Verified by; Approved by; Lydia Tan 8