A-LevelBiologyEnzymes9700/12 · Feb/Mar 2025 · Q141 Mark
Catalase is an enzyme that breaks down hydrogen peroxide into water and oxygen. Catalase was added to a solution of hydrogen peroxide and the oxygen produced was collected in a gas syringe. The total volume of oxygen produced from the start of the reaction was recorded every 10 seconds for 1 minute. The results are shown in the table. time/s: 0, total volume of oxygen produced/cm³: 0 time/s: 10, total volume of oxygen produced/cm³: 22 time/s: 20, total volume of oxygen produced/cm³: 40 time/s: 30, total volume of oxygen produced/cm³: 50 time/s: 40, total volume of oxygen produced/cm³: 55 time/s: 50, total volume of oxygen produced/cm³: 57 time/s: 60, total volume of oxygen produced/cm³: 58 What can be concluded from these results?
AThe reaction stopped after 60 seconds and no more oxygen was produced.
BThe highest rate of oxygen production occurred 10 seconds after the start of the reaction.
CIt took more than 20 seconds from the start of the reaction for half of the substrate to be converted to water and oxygen.
DThe mean rate of reaction between 20 and 30 seconds was twice the mean rate of reaction between 30 and 40 seconds.
✓ Correct answer
D: The mean rate of reaction between 20 and 30 seconds was twice the mean rate of reaction between 30 and 40 seconds.
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