A technician grows one species of bacterium in sterile nutrient broth. The conditions remain suitable throughout the investigation.
The technician takes the same volume of broth after 0 minutes and after 75 minutes. Each sample is spread onto a separate nutrient agar plate. Each bacterium in a sample produces one colony.
| Time the broth had been incubated in minutes | Number of well-separated colonies |
|---|---|
| 0 | 24 |
| 75 | 192 |
Name the process by which each bacterium divides into two identical cells.
Use the table to calculate the mean division time of the bacteria.
A second culture of the same species starts with 90 bacteria. The second culture is kept under the same conditions for 100 minutes.
Calculate the number of bacteria in the second culture after 100 minutes.
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.