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Osmosis in potato cells

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Osmosis in potato cells Planning I am going to investigate the effect of different sugar concentrations on different pieces of potato, also I will be able to find the concentration inside the potato cells at the same time. The concentration of the sugar solutions will affect the experiment, from preliminary work I have found this out, osmosis will occur differently depending on the sugar concentrations. The time the potato disks are left in the concentrations will also affect it, the concentration might not have equalled throughout, reaching the situation of net flow. So by preliminary work, I realised after 25 minuets the rate of change of mass either decreased considerably or stopped completely, meaning they were either at or very near the situation of net flow. The sizes and amount of surface area of the potatoes will affect the experiment. This is because, for example, if the piece of potato has a big surface area the water molecules will come in/out of it at a much less time than one that has a small surface area. Because different potatoes have different sugar concentration and cell density. Therefore this could also effect in the experiment. I want to find the effect the different sugar solutions have on the potato cells, so I am only going to change this. To make the experiment fair I will: * Use 5cm� of the sugar solution for each test. ...read more.


So when the concentration is lower outside the potato cell the water passes into the vacuole of the potato, as a consequence the cell swells up, becomes turgid and therefore the weight increases. I'm not quiet sure what the potato cells concentrations will be, all I know is, from my preliminary work, that it is somewhere roundabout 3(m), because that was where the weight hardly changed therefore the concentration was nearly the same. Therefore that being near the concentration in the vacuole of the cell. Table of results Sugar concentration (m) Original Mass of potato discs (g) Mass of the potato discs after being in the concentration (g) Change in mass (g) % Change in mass 1 2 3 4 5 6 Obtaining evidence I did the experiment safely by doing preliminary work before hand so I knew nothing could go drastically wrong, I didn't break anything or nothing along those lines so I would say it was a safe experiment and suitable for what I wanted to find out. I left the potatoes in the solutions overnight; this was because I didn't have time to weigh them after 25 minutes so I had to leave them until the next day. When I weighed them the next day they had all decreased in weight (gone flaccid), I think this was because the water out of the sugar solutions had been evaporating while they was left so the concentration would have got stronger. ...read more.


The results that appeared very similar could be averaged and used for plotting the graph and the anomaly ignored if there were any so it wouldn't ruin the final results. To ensure the experiment was the most accurate that I could get it, I used accurate apparatus with the most suitable scale for setting up the experiment and obtaining the results. But I don't think it was very accurate that when getting the potatoes out of the solution that you had to damp the excess water off, because you had to be careful not to dry it out too much or it could ruin the results by absorbing the water back out of the potato. The second result for the 0.0m concentrations was an anomaly, this could have been caused by being dried too much therefore taking too much water off it, and so it would weigh less than it should of. I collected enough evidence to draw a graph off and to see a pattern so I am confident about my conclusion. The further work I could do is to do each experiment 3 times making it more reliable and to put corks on the end of the test tubes stopping any water from being evaporated from the solution. Do the concentrations in-between of 0.4 to 0.6 to see exactly and more accurately which concentration the potatoes are. ...read more.

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