Two varieties of a crop were grown in the same nutrient solution under the same conditions. The magnesium ion concentration in the nutrient solution was lower than in the root hair cells of both varieties.
| Variety | Mean number of mitochondria per root hair cell | Magnesium ion uptake rate (μ \mu\,μg per 106 10^6\,106 root hair cells per hour) |
|---|---|---|
| A | 300 | 0.80 |
| B | 540 | 1.20 |
Calculate the percentage increase in magnesium ion uptake rate in variety B compared with variety A.
Explain how the difference in root hair cell structure could account for the difference in magnesium ion uptake rates.
80 exam-style questions on Edexcel GCSE Biology 6.2 Transport in plants, covering 6.2.1 Root hair cell adaptations, 6.2.2 Structure of xylem and phloem, 6.2.3 Transpiration and stomata, 6.2.4 Translocation of sucrose, 6.2.5 Leaf structure for photosynthesis, 6.2.6 Environmental factors on water uptake, 6.2.7 Rate calculations for transpiration, and 6.2.8 Plant adaptations to extreme environments. Each one has a worked solution and a mark scheme showing where the marks go.