Catalase is an enzyme that catalyses the breakdown of hydrogen peroxide, which is a waste product of cell metabolism. The reaction catalysed by catalase is shown in Fig. 6.1. [Figure 6.1]

1. (a)(i)A student carried out two experiments to investigate the progress of the reaction shown in Fig. 6.1. Potato tissue was used as the source of the enzyme. Six pieces of potato were cut, each measuring 20mm x 10mm x 10mm. In the first experiment, hydrogen peroxide solution was added to three of the pieces of potato tissue and the progress of the reaction was measured. Fig. 6.2 shows how the first experiment was set up. [Figure 6.2] Suggest how the progress of the reaction could be measured.[2]
2. (a)(ii)In the second experiment, the student cut each of the three remaining pieces of potato to obtain six pieces, each measuring 10mm x 10mm x 10mm. Using exactly the same conditions, the student measured the progress of the reaction and obtained different results to the first experiment. Explain why the results of the second experiment were different from the results of the first experiment.[2]
3. (b)The student then investigated the effect of temperature on the activity of catalase. On Fig. 6.3, sketch a curve to show how temperature affects the activity of an enzyme such as catalase. [Figure 6.3][1]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.