A school laboratory needs to grow a harmless soil bacterium, H. At least 1.0 × 104 bacteria are needed after 4 hours.
The culture could be accidentally contaminated with a human pathogen, P. Researchers started each culture with the same number of bacteria and measured the populations after 4 hours.
| Incubation temperature in °C | Number of H bacteria after 4 hours | Number of P bacteria after 4 hours |
|---|---|---|
| 20 | 3.0 × 103 | 1.2 × 102 |
| 25 | 1.2 × 104 | 4.0 × 102 |
| 30 | 2.5 × 104 | 1.5 × 104 |
| 37 | 4.0 × 104 | 6.0 × 104 |
Using the information in the table, explain why 25 °C is the most suitable incubation temperature for the school laboratory.
282 exam-style questions on AQA GCSE Biology 1.1 Cell structure, covering 1.1.1 Eukaryotes and prokaryotes, 1.1.2 Animal and plant cells, 1.1.3 Cell specialisation, 1.1.4 Cell differentiation, 1.1.5 Microscopy, and 1.1.6 Culturing microorganisms. Each one has a worked solution and a mark scheme showing where the marks go.