Equal quantities of starch are completely broken down by the same enzyme at different pH values. All other conditions are kept the same.
Table
| pH | Time for starch to disappear / s |
|---|---|
| 4 | 120 |
| 5 | 60 |
| 6 | 30 |
| 7 | 90 |
Which comparison of the reaction rates is correct?
The rate at pH 6 is three times the rate at pH 7.
The rate at pH 7 is three times the rate at pH 6.
The rate at pH 4 is twice the rate at pH 5.
The rate at pH 5 is twice the rate at pH 6.
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.