An enzyme is heated to 90 ∘C90\,^{\circ}\mathrm{C}90∘C and then cooled to 30 ∘C30\,^{\circ}\mathrm{C}30∘C. Its substrate is added, but no product forms.
Fresh enzyme is then added and product forms rapidly.
Which conclusion is best supported?
Heating used up all the substrate; the enzyme active sites remained suitable.
Cooling changed the substrate shape; the heated enzyme remained suitable.
Cooling used up all the enzyme; the substrate active sites remained suitable.
Heating changed the enzyme active sites; the substrate remained suitable.
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.