An investigator studied the water potential of apple (Malus domestica) tissue by measuring changes in mass of apple cylinders when immersed in sodium chloride (NaCl) solutions of various concentrations.
The method used was as follows:
The results obtained are shown in the table below:
| Concentration of NaCl solution (mol/dm3\text{mol/dm}^3mol/dm3) | Initial mass of cylinder (g\text{g}g) | Final mass of cylinder (g\text{g}g) |
|---|---|---|
| 0.00.00.0 (distilled water) | 5.005.005.00 | 5.605.605.60 |
| 0.20.20.2 | 4.804.804.80 | 5.045.045.04 |
| 0.40.40.4 | 5.205.205.20 | 5.205.205.20 |
| 0.60.60.6 | 5.005.005.00 | 4.704.704.70 |
| 0.80.80.8 | 4.804.804.80 | 4.204.204.20 |
Calculate the percentage change in mass of the apple cylinder immersed in the 0.8 mol/dm30.8\text{ mol/dm}^30.8 mol/dm3 NaCl solution. Show your working.
Explain, in terms of water potential and osmosis, why the mass of the apple cylinder in distilled water (0.0 mol/dm30.0\text{ mol/dm}^30.0 mol/dm3) increased, while the mass of the apple cylinder in 0.8 mol/dm30.8\text{ mol/dm}^30.8 mol/dm3 NaCl solution decreased.
30 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.