After the experiment, I found that my prediction was correct. Batch A, B and C have a small concentration of solution and a high change in mass. Plant cells are surrounded by a fully permeable cell wall. This will not let any molecules pass through. As a result osmosis will not occur. Osmosis will occur through the partially permeable cell membrane, when a plant is in pure water. The cytoplasm and vacuole swell as the water goes in. However, the cell wall is stronger than the cell membrane, so the plant cell doesn’t burst. The plant is then turgid because the plant cell has been blown-up like a ‘tyre’. Plant cells are usually turgid.
A plant in pure water:
Batch D, E and F have a high concentration of solution and a decrease in mass. Plant cells plasmolyse in concentrated solutions. Unlike batch A, B and C, the cytoplasm and the vacuole will shrink instead of swelling. Now the cell is flaccid because some of the air has leaked out and the ‘tyre’ becomes floppy. Because there is a high concentration of solution, a lot of water diffuses out of the cell. In the end after the cytoplasm has shrunk even more the cell membrane surrounding the cytoplasm tears away from the cell wall. Now the cell is plasmolysed. This would not occur if the concentration of solution surrounding the plant cell was low. In the end plasmolysis will kill the plant cell because the cell membrane is too damaged.
A burst plant cell:
Evaluation: This experiment was only repeated once, so therefore it is not an accurate experiment. To improve my experiment in the future I will repeat it 3 times to get more accurate results. At o.4M on my graph there is an anomolous result. You could avoid this anomolous result by repeating the experiment 3 times. To improve the whole experiment if I were to do it again I would repeat the experiment 3 times, so that you can calculate an average and make the results more accurate. I would also use a greater range of concentrations such as 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 or 0.0, 0.2, 0.4, 0.6, 0.8, 1.0. I would also use more accurate equipment to measure the volume of the liquid such as a burette or maybe a ruler. Also I would use a different kind of cell instead of a potato cell, for example a celery cell or an onion cell.
My Graph:
