A student made two model cells using sealed bags of partially permeable membrane. Each bag contained the same unknown concentration of sugar solution. Water could pass through the membrane but sugar could not.
The student placed each bag in a different sugar solution for 45 minutes. The student then dried the outside of each bag and measured its final mass.
| Concentration of surrounding sugar solution in mol/dm³ | Initial mass of bag in g | Final mass of bag in g |
|---|---|---|
| 0.20 | 15.00 | 15.60 |
| 0.50 | 12.50 | 12.25 |
Calculate the percentage change in mass of each bag.
Assume that the relationship between the concentration of the surrounding solution and the percentage change in mass is linear between the two results.
Calculate the concentration of the sugar solution inside the bags.
A third bag containing the same sugar solution is placed in a 0.70 mol/dm³ sugar solution.
Suggest how the mass of the third bag will change. Explain your answer.
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.