Two varieties of radish are grown with their roots in the same nutrient solution.
The table shows the magnesium ion concentrations.
| location | magnesium ion concentration in mmol dm⁻³ |
|---|---|
| nutrient solution | 0.40 |
| root hair cells of variety P | 2.00 |
| root hair cells of variety Q | 2.00 |
The root hair cells of variety P contain more mitochondria than those of variety Q. The cells have the same surface area and membrane thickness.
What is the most likely difference in magnesium ion uptake between the varieties?
Both varieties have equal magnesium ion uptake because their cells have the same internal concentration.
Variety P has faster magnesium ion uptake because its cells release more energy for active transport.
Variety P has slower magnesium ion uptake because its cells use more energy during osmosis.
Variety Q has faster magnesium ion uptake because its cells have fewer mitochondria using magnesium ions.
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.