A scientist investigates hormone X in a mammal. At time 0, a medicine prevents the endocrine gland from secreting any more hormone X. The scientist measures the concentration of hormone X dissolved in the blood plasma every 3 minutes.
| Time in minutes | Concentration of hormone X in ng dm⁻³ |
|---|---|
| 0 | 24 |
| 3 | 12 |
| 6 | 6.0 |
The scientist predicts that the pattern shown by the results will continue.
Calculate the concentration of hormone X in the blood at 15 minutes.
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.