A student compares untreated amylase with amylase that has been boiled. The boiled amylase is added to starch while still hot. The untreated amylase is added to starch at 30 ∘C30\,^{\circ}\mathrm{C}30∘C.
Which change would best isolate the effect of boiling the enzyme?
Heat the untreated amylase to boiling before adding it to starch at 30 ∘C30\,^{\circ}\mathrm{C}30∘C.
Cool the boiled amylase to 30 ∘C30\,^{\circ}\mathrm{C}30∘C before adding it to starch at 30 ∘C30\,^{\circ}\mathrm{C}30∘C.
Cool the boiled amylase to 30 ∘C30\,^{\circ}\mathrm{C}30∘C before adding it to starch at 60 ∘C60\,^{\circ}\mathrm{C}60∘C.
Heat the untreated amylase to 60 ∘C60\,^{\circ}\mathrm{C}60∘C before adding it to starch at 60 ∘C60\,^{\circ}\mathrm{C}60∘C.
44 exam-style questions on Edexcel GCSE Biology 1.3 Enzymes, covering 1.3.1 Mechanism of enzyme action, 1.3.2 Denaturation of enzymes, 1.3.3 Factors affecting enzyme activity, and 1.3.4 Measuring energy in food by calorimetry. Each one has a worked solution and a mark scheme showing where the marks go.