An enzyme completely breaks down a sample of substrate. An equal fresh sample of the substrate is added to the same enzyme solution, and this is also broken down. Temperature and pH are unchanged.
Which statement explains the second reaction?
The enzyme becomes the product, so its active sites can bind fresh substrate.
The substrate becomes the enzyme, so each reaction produces new active sites.
The product becomes the substrate, so each reaction produces new active sites.
The enzyme is not used up, so its active sites can bind fresh substrate.
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.