A student measures the time for a fixed quantity of starch to disappear in four repeats.
Table
| Repeat | Time / s |
|---|---|
| 1 | 48 |
| 2 | 50 |
| 3 | 95 |
| 4 | 52 |
Repeat 3 is excluded because the enzyme volume was measured incorrectly.
The student calculates a relative rate using
relative rate=1mean time \text{relative rate}=\frac{1}{\text{mean time}} relative rate=mean time1What relative rate should the student obtain?
0.016 s−10.016\,\mathrm{s^{-1}}0.016s−1
0.020 s−10.020\,\mathrm{s^{-1}}0.020s−1
0.060 s−10.060\,\mathrm{s^{-1}}0.060s−1
0.0067 s−10.0067\,\mathrm{s^{-1}}0.0067s−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.