A student mixes 2 cm3 of a 3% starch solution with 2 cm3 of water and 2 cm3 of amylase solution.
At these low starch concentrations, the initial reaction rate is directly proportional to the initial starch concentration. At an initial starch concentration of 0.5%, the rate is 4 mg min−14\,\mathrm{mg\,min^{-1}}4mgmin−1 with the same final amylase concentration, temperature and pH.
What initial rate is predicted for the student's mixture?
12 mg min−112\,\mathrm{mg\,min^{-1}}12mgmin−1
16 mg min−116\,\mathrm{mg\,min^{-1}}16mgmin−1
8 mg min−18\,\mathrm{mg\,min^{-1}}8mgmin−1
24 mg min−124\,\mathrm{mg\,min^{-1}}24mgmin−1
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.