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The Effect of Osmosis in potatoes.

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Introduction

Coursework: The Effect of Osmosis in potatoes Henry Agyei 10 Lowry Aim: The aims of the experiment are: * To see whether different concentrations of sucrose solution (0%, 0.25%, 0.5%, 0.5%, 0.75%, 1%) have effects on the size and weight of cylinders of potato that are put into them. * Also I aim to find out which of the concentrations affect the potato cylinders in size and weight the most and the least. Prediction: I predict that the concentration which will affect the size an weight the least will be 0.5. The 1.0 will lessen the weight of the potato cylinders but not the size, because there is a higher concentration of sucrose in it; and therefore a low region of water. I think this because I think that more water will come out of the cell than into the cell. The distilled water will add to the to the weight of the potato cylinder because there is more water in it so that osmosis can easily occur. Here I think more water will come into the cell than out of the cell. ...read more.

Middle

1 5 4.94 7.4 7.4 2 5 5 6.9 6.85 3 5 4.93 8.0 7.84 Average 5 4.97 7.7 7.36 1.0% Length before(cm) Length after(cm) Weight before (grams) Weight after (grams) 1 5 4.95 6.3 6.1 2 5 4.87 6.7 6.4 3 5 4.97 7.4 7.0 Average 5 4.93 6.84.97 6.55 Conclusion: The conclusion of my experiment is that the potato cylinders in the distilled water gained in weight on average. This is because the distilled water had a region of higher concentrated water than the cells of the potato. The water molecules were therefore able to flow both in and out of the cell membrane, but after the 25 minutes had passed, more water had entered into the cell of the potato than left it. The potato cylinder that was in the distilled water shortened in size a little on th1 1st and 3rd attempts. This is because the cell membrane had become saturated with water molecules that had come into the cell and the potato cylinder had shrunk as a result of that. The 0.25 concentration showed that it had on average lessened in size but grown in weight. ...read more.

Conclusion

In this case there is much less water from a dilute solution through a semi-permeable membrane to a more concentrated solution. When you put an animal or plant cell into liquid containing water one of three things will happen. * If the medium surrounding the cell has a higher water concentration than the cell (a very dilute solution) the cell will gain water by osmosis. Water molecules are free to pass across the cell membrane in both directions, but more water will come into the cell than will leave. The overall result is that water enters the cell. The cell will swell up. * If the medium is exactly the same water concentration as the cell there will be no net movement of water across the cell membrane. Water crosses the cell membrane in both directions, but the amount going in is the same as the amount going out, so there is no overall movement of water. The cell will stay the same size. * If the medium has a lower concentration of water than the cell (a very concentrated solution) the cell will lose water by osmosis. The water crosses the cell membrane in both directions, but more water leaves the cell than enters it and so the cell shrinks. ...read more.

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