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Demonstration of the catalytic action of enzymes. 3.1. Demonstration of the catalytic action of enzymes. 1 What is the purpose of grinding the liver tissues?. This breaks down liver tissues to release catalase. 3.1. Demonstration of the catalytic action of enzymes.
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3.1 Demonstration of the catalytic action of enzymes 1 What is the purpose of grinding the liver tissues? This breaks down liver tissues to release catalase.
3.1 Demonstration of the catalytic action of enzymes 2 Why is it better to use cool distilled water to grind the liver tissues? Grinding action produces heatwhich may destroy the enzymes.
3.1 Demonstration of the catalytic action of enzymes 3 What does the relighting of a glowing splint indicate? The gas given off is oxygen. 4 What is the reason for repeating the procedure with distilled water instead of hydrogen peroxide? It is a control experiment to show that oxygen does not come from the liver extract.
3.1 Demonstration of the catalytic action of enzymes 5 What is the reason for repeating the procedure with distilled water instead of liver extract? It is a control to show that oxygen is not given off from the hydrogen peroxide. 6 What do the results of the experiment tell? Liver extract reacts with hydrogen peroxide to produce oxygen.
3.1 Demonstration of the catalytic action of enzymes 7 Does this experiment directly 直接 show the catalytic action (催化作用) of catalase? If not, what further experiment can be done to show this? No. This experiment only shows that the breakdown of hydrogen peroxide is speeded up (加快) by the liver extract. If a boiled liver extract is used and it does not work, then the reaction is due to enzyme(s).
3.1 Demonstration of the catalytic action of enzymes 8 Do you think this experiment is a fair test? Explain.難 Yes. For the three test tubes, only one variable (the sample) is changed at a time, the others (e.g. the volume and temperature of hydrogen peroxide, liver extract and distilled water) are kept constant.
3.1 Demonstration of the catalytic action of enzymes Conclusion What conclusion can you draw from this practical? The breakdown of hydrogen peroxide is catalysed by the liver extract, probably by an enzyme in liver tissue. Nevertheless, further experiments should be done to confirm this.
