A researcher measures the concentration of urea in blood entering and leaving two organs in a seal.
| Organ | Urea concentration in blood entering the organ (mmol dm−3\text{mmol dm}^{-3}mmol dm−3) | Urea concentration in blood leaving the organ (mmol dm−3\text{mmol dm}^{-3}mmol dm−3) |
|---|---|---|
| X | 4.2 | 4.7 |
| Y | 4.5 | 3.8 |
Explain which organ is X and which organ is Y.
The seal then eats fish containing more protein than its cells need.
Suggest how this would affect the concentration of urea in the blood leaving organ X. Explain your answer.
114 exam-style questions on OCR GCSE Biology 2.2 The challenges of size, covering 2.2.1 Exchange surfaces and surface area : volume ratio, 2.2.2 Substances transported in organisms, 2.2.3 The human circulatory system, 2.2.4 The heart and blood vessels, 2.2.5 Red blood cells and plasma, 2.2.6 Uptake of water and mineral ions by plants, 2.2.7 Transpiration and translocation, 2.2.8 Xylem and phloem, 2.2.9 Environmental factors and water uptake, and 2.2.10 Using a potometer. Each one has a worked solution and a mark scheme showing where the marks go.