Scientists separate a sample of blood into plasma and red blood cells. They measure how much oxygen is carried in each component.
| Blood component | Volume of oxygen carried in the sample (cm3\text{cm}^{3}cm3) |
|---|---|
| Plasma | 0.3 |
| Red blood cells | 20.0 |
Tests also show that glucose and urea are present in the plasma.
Calculate the percentage of the total oxygen in the sample that is carried by the red blood cells.
Explain why glucose and urea are transported in the plasma, but most oxygen is transported in the red blood cells.
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.