A scientist measured the concentration of a hormone in blood samples taken from four blood vessels in the same person.
The Table shows the mean results.
Table
| Blood vessel | Mean concentration of hormone in arbitrary units |
|---|---|
| artery entering the thyroid gland | 12 |
| vein leaving the thyroid gland | 48 |
| vein leaving the leg muscle | 11 |
| vein leaving the kidney | 12 |
Calculate how many times greater the concentration of the hormone is in the vein leaving the thyroid gland than in the artery entering the thyroid gland.
Explain what the results show about where this hormone is produced.
Suggest why the concentration of the hormone in the vein leaving the leg muscle is lower than in the artery entering the thyroid gland.
The scientist took several blood samples from each blood vessel and calculated a mean.
Give one reason why.
A student concluded that the thyroid gland is the only gland that releases this hormone.
Explain why the data do not fully support this conclusion.
42 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.