Plant cells are also closely crowded together, so that if some cells lose water and as a consequence their cytoplasm becomes more concentrated, they may attract water from neighbouring cells until they all have an equal water content. This equalling-out process is how water passes from cell to cell across a root, or inside a leaf, for instance.
Plasmolysis
If a plant does not get enough water, then its cells may become plasmolysed due to water leaving the vacuole. When the cell contents peel away from the cell wall, the cell membrane becomes visible (under the microscope), and the plant wilts.
The principle of osmosis is used in the preservation of food, kept in strong solutions of salt (brine), or sugar (syrup), Any bacteria which gain access to the food become plasmolysed as above, and are effectively killed by dehydration.
These examples should remind us that osmosis is only a type of diffusion, and also that it is not even a special property of living organisms. It is, however, important in biological systems because every cell of all living organisms contains a certain amount of water, and is bounded by a partially permeable membrane, through which exchange of water (and other substances) may occur with its surroundings.
Therefore I predict that the potato will absorb water and grow but at a certain concentration of sugar that is higher then in the concentration of sugar in the potato, the potato will shrink due to loss of water. This will cause the potato to become flaccid.
Results
Pilot
*This is an anomalous result.
Graph
See graph titled “Pilot”
Analysis
As you can see from the graph and the results table the result for the 10% concentration was anomalous. The exact reason for this is unknown, but it is probably an error in setting up the experiment causing the 5% concentration to have been thought to be the 10% concentration so the 5% concentration was repeated.
Evaluation
The results appear to be correct and can be relied on because the line of best fit is close to all points with the exception of the anomalous result for 10% concentration. For the next part of the test I will make sure that the experiment is set up properly so that no similar mistakes can occur.
Actual test
Results
Average of the test repeated twice
Graph
See graph titled “average”
Analysis
Up to a certain point the potato absorbed water but after that point (5%) it lost water. This means that the potato must have about 5% concentration of sugar inside.
This has proved my prediction correct as it has done exactly what I predicted and the potatoes that grew did become turgid, the ones that shrank became flaccid.
Evaluation
I think that the results in this section of the experiment are reliable as the line of beat fit practically touches every point on the graph and there are no anomalous results meaning that no huge errors were made.
If I were to redo this test I wouldn’t change many things, as I believe it is a good method for this experiment. I don’t think that by gathering more results I would make the results more reliable but I do think that if the test was to be repeated a lot more the more reliable would be.
I think that the method used for this test was good as the data collected was accurateand the amount of data collected was also a good amount, not too little to give bad results but not to big to give huge amounts of data that would be pointless.
If I was to extend this experiment I would repeat the experiment, but with a different lengths of potato for each time I repeated it.
