Scientists investigated the automatic control of blood glucose concentration in a seal. The optimum concentration was 5.0 mmol/dm³.
At 0 minutes, immediately before the seal ate a glucose-rich feed, its blood glucose concentration was measured. Further measurements were taken after feeding.
| Time in minutes | Blood glucose concentration in mmol/dm³ |
|---|---|
| 0 | 5.0 |
| 30 | 7.4 |
| 60 | 7.8 |
| 90 | 8.1 |
A gland is the effector in this control system. When stimulated, the gland releases a hormone that helps to restore blood glucose concentration towards the optimum.
The scientists carried out tests on the control system.
| Test | Observation |
|---|---|
| The receptors detected the rise and information reached the coordination centre. | Yes |
| Information from the coordination centre reached the gland. | No |
| The gland released the hormone when stimulated directly. | Yes |
Suggest which part of the automatic control system is faulty. Use the test results to justify your answer.
Explain why this fault could produce the pattern in blood glucose concentration shown in the first table.
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.