The table compares three processes that move substances across a cell membrane. Two entries have been replaced by the letters X and Y.
Table: A comparison of the substances moved and the energy needed in diffusion, osmosis and active transport
| Process | Substance moved | Energy from respiration needed |
|---|---|---|
| Diffusion | Any small, soluble substance | No |
| Osmosis | X | No |
| Active transport | Dissolved substances such as mineral ions | Y |
Give the correct entry for X and the correct entry for Y.
A plant cell is put into a solution that is more concentrated than its cytoplasm.
Describe what happens to the water in the cell, and name the process responsible.
When a cell is cooled from 20 °C to 5 °C the rate of active transport into the cell falls sharply, but the rate of diffusion into the cell falls by much less.
Explain why.
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.