Hormone M is produced by endocrine gland G and affects target organ K.
Scientists investigate mammal Q, in which organ K has unusually low activity. They compare mammal Q with a healthy mammal after gland G is stimulated in the same way.
| Measurement | Healthy mammal | Mammal Q |
|---|---|---|
| rate of hormone M production by gland G (ng/min) | 10.4 | 10.3 |
| rate at which hormone M enters the blood plasma (ng/min) | 8.6 | 8.5 |
| released hormone M that reaches organ K within 20 seconds (%) | 74 | 75 |
Scientists also expose samples of organ K to different concentrations of hormone M.
| concentration of hormone M (ng/cm³) | increase in activity of healthy organ K sample (%) | increase in activity of mammal Q organ K sample (%) |
|---|---|---|
| 2.0 | 9 | 1 |
| 4.0 | 18 | 3 |
| 6.0 | 27 | 4 |
Explain which process in the hormone pathway is defective in mammal Q. Use the data and predict whether raising the concentration of hormone M at organ K to 6.0 ng/cm³ would restore a normal response.
89 exam-style questions on Edexcel GCSE Biology 7.1 Hormones and coordination, covering 7.1.1 Endocrine glands and hormone transport, 7.1.2 Adrenalin and fight or flight, and 7.1.3 Thyroxine and negative feedback. Each one has a worked solution and a mark scheme showing where the marks go.