An enzyme is used to remove a substrate from a liquid during food processing.
A scientist records the time taken for a fixed mass of the substrate to disappear at different temperatures. The pH and the volumes and concentrations of the enzyme and substrate are kept the same.
| Temperature in ∘C^\circ\text{C}∘C | Time taken in s\mathrm{s}s |
|---|---|
| 15 | 300 |
| 25 | 150 |
| 35 | 75 |
| 45 | 50 |
| 55 | 250 |
Give the best estimate of the enzyme's optimum temperature from these results.
A fresh sample of the enzyme is kept at 55 ∘C55\ ^\circ\text{C}55 ∘C for five minutes and then cooled to 25 ∘C25\ ^\circ\text{C}25 ∘C before the substrate is added.
Predict how the time taken for the substrate to disappear would compare with 150 s.
Explain your prediction.
184 exam-style questions on OCR GCSE Biology 1.2 What happens in cells (and what do cells need)?, covering 1.2.1 Structure of DNA, 1.2.2 Nucleotides and complementary bases, 1.2.3 Protein synthesis, 1.2.4 DNA structure and the proteins made, 1.2.5 Investigating enzymatic reactions, and 1.2.6 Mechanism of enzyme action. Each one has a worked solution and a mark scheme showing where the marks go.