Seedlings were grown with their roots in a nutrient solution. A chemical was used to reduce only the rate of respiration in the root hair cells.
| Measurement | Result |
|---|---|
| Nitrate ion concentration in the nutrient solution | 0.40 mmol/dm³ |
| Nitrate ion concentration inside the root hair cells | 8.0 mmol/dm³ |
| Nitrate ion uptake rate with normal respiration | 15.0 µmol per gram per hour |
| Nitrate ion uptake rate with reduced respiration | 3.0 µmol per gram per hour |
Explain why the results support the conclusion that nitrate ions enter the root hair cells by active transport. Predict how having fewer mitochondria would affect the rate of nitrate ion uptake.
140 exam-style questions on AQA GCSE Biology 1.3 Transport in cells, covering 1.3.1 Diffusion, 1.3.2 Osmosis, and 1.3.3 Active transport. Each one has a worked solution and a mark scheme showing where the marks go.