A student investigated osmosis using two samples of pear tissue. The samples had the same initial total volume and mass.
Sample R was one cube. Sample S was eight smaller cubes. The student placed each sample in the same volume and concentration of dilute sugar solution for 15 minutes. The temperature was kept constant.
| Sample | Number of cubes | Length of each side in cm | Total volume in cm³ | Initial mass in g | Mass after 15 minutes in g |
|---|---|---|---|---|---|
| R | 1 | 2 | 8 | 8.00 | 8.24 |
| S | 8 | 1 | 8 | 8.00 | 8.40 |
Calculate the surface area to volume ratio of each sample.
A student concluded, “The total surface area of sample S is twice that of sample R, so its mean rate of mass gain is twice as great.”
Evaluate the student's conclusion. Use the results and your knowledge of osmosis.
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.