The optimum internal pH of a cell is 7.2.
At 0 minutes, the cell was transferred from a solution at pH 7.2 to a solution at pH 6.0. The cell remained in the solution at pH 6.0.
| Time after transfer in minutes | Internal pH of the cell |
|---|---|
| 0 | 7.2 |
| 2 | 6.8 |
| 5 | 7.0 |
| 8 | 7.2 |
Which conclusion is best supported by the measurements?
The results support homeostasis because the internal pH decreased towards the pH of the external solution.
The results do not support homeostasis because the final internal pH matched the starting pH, so no response occurred.
The results do not support homeostasis because the internal pH was below the optimum at two readings.
The results support homeostasis because the internal pH decreased and then returned towards the optimum over successive readings.
76 exam-style questions on AQA GCSE Biology 5.1 Homeostasis, covering 5.1 Homeostasis. Each one has a worked solution and a mark scheme showing where the marks go.