A horticulturist compares water uptake by two rooted seedlings. The roots of each seedling are enclosed in a water-filled chamber connected to a calibrated capillary tube. A marker in each tube moves towards the chamber as water is taken up by the roots.
The seedlings are tested for the same period of time.
| Seedling | Marker movement in 12.0 minutes (mm) | Volume represented by 1.0 mm movement (mm3\text{mm}^3mm3) |
|---|---|---|
| P | 24.0 | 0.40 |
| Q | 27.0 | 0.20 |
The horticulturist concludes that seedling Q takes up water faster because its marker moves further.
Calculate the rate of water uptake for each seedling in mm3\text{mm}^3mm3 per minute. Evaluate the horticulturist's conclusion.
Show your working.
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.