INDEX NUMBER:______________
MATRICULATION AND SECONDARY EDUCATION CERTIFICATE EXAMINATIONS BOARD
UNIVERSITY OF MALTA, MSIDA
MATRICULATION CERTIFICATE EXAMINATION
ADVANCED LEVEL
SPECIMEN PAPER
SUBJECT:
PAPER NUMBER:
DATE:
TIME:
BIOLOGY
IV (Practical)
2008-2010
1 hr 30 mins
The enzyme catalase acts on hydrogen peroxide to release oxygen according to this
equation.
Catalase
2H2O2
2H2O
+
O2
Squares of filter paper dipped in catalase solution are placed in hydrogen peroxide
solutions. Small oxygen bubbles are evolved and adhere to the surface of the filter
paper which eventually floats to the surface. The time taken for this to occur is noted
and is taken as a measure of the speed at which the reaction is proceeding.
You are provided with squares of filter paper, a 1% catalase solution, a standard
hydrogen peroxide solution and distilled water. In addition you are provided with
some syringes and a number of plastic/ glass containers.
Plan and carry out an experiment to investigate the effect of varying the substrate
concentration on the rate of this enzyme catalysed reaction.
Answer the following questions:
1. Describe the method you use including :
(i) how the dilutions are carried out (suggestion: in table form);
[three marks]
(ii) the procedure you use in setting up the various reaction mixtures;
[five marks]
(iii) how you took readings to measure the rate of the reaction;
[five marks]
(iv) any precautions taken to ensure accuracy.
[three marks]
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(iv)__________________________________________________________________
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2. Present the results you obtain in table form.
[four marks]
3. Plot a graph to show your results.
[four marks]
4.
(i) Describe any trend that emerges from your graph.
[three marks]
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(ii) By referring to your knowledge of enzyme action, give reasons for these results.
[five marks]
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(iii) List TWO sources of error in your investigation.
[two marks]
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(iv) What conclusions can you reach on the effect of varying the substrate
concentration on the rate of this particular enzyme catalysed reaction?
[four marks]
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5. Give ONE reason why this reaction is unsuitable for determining the effect of
variations in temperature on an enzyme catalysed reaction.
[two marks]
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[Total: 40 marks]
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