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Osmosis in Living Tissue.

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Introduction

Will Carroll 01 May 2007 Osmosis in Living Tissue Planning Osmosis is the movement of water from a high water concentration to one of low water concentration, through a selectively permeable membrane. The object of this is to even out the concentrations of the solutions, regardless of the volumes of the solutions. Osmosis Diagrams: Plasmolysis: Movement of Molecules The movement of molecules inside a solution of high water concentration is fast, and so they have more chance of getting through the semi-permeable membrane, and changing the concentration of the solution that has a low water concentration. The things that change the rate that osmosis occurs are: * The Concentration * The Surface area * The Temperature The concentration affects the rate of reaction because if one of the solutions is pure water, and the other is very concentrated with sucrose, the rate will be faster as there are more molecules to move past the semi- permeable membrane, so they will move faster. The surface area affects the rate of osmosis because it means that there will be more of the semi-permeable membrane for the molecules to collide with, and penetrate through. ...read more.

Middle

0.0 17.0 0.0 -1.4 -3.3 14.7 -3.3 8.0 10.0 1.0 3.3 -8.0 -3.3 18.9 0.6 -3.6 -3.3 -7.4 -6.6 6.2 1.0 -5.5 -3.3 -11.4 -3.3 10.0 3.2 -2.4 -2.6 -11.0 -5.2 The Constants: * The dimensions of the chip * The amount of solution * The concentration of the solution * The room temperature * The time in the solution In this investigation we are measuring the mass and the length of the chip, before and after it was put in the different solutions. Here is a graph of the Preliminary results: Prediction: The prediction that we have made for this experiment is that when the concentration of the sugar solution increases, the mass and the length of the chip will decrease. This is because when there is more sugar in one of the solutions, then osmosis will take place, and will level out the concentrations of the two solutions. This can be proved from the results of the preliminary experiment, as when the solution was 1.0 mol/dm�, the percentage mass change was -11.0, and the percentage length change was -5.2. ...read more.

Conclusion

0 -10 -3.3 1.0 1.0 1.0 0.8 0.9 0.9 -0.2 -0.1 -0.1 -20 -10 -10 -13.3 1.0 1.0 1.0 0.9 0.8 0.8 -0.1 -0.2 -0.2 -10 -20 -20 -16.7 Conclusion The results show that our prediction was right, I that when the concentration of the sugar solution increased, the mass and length decrease. This is because of osmosis. There are more water particles in the chip than the sugar solution, so the water molecules pass through the membrane and level out the concentration of the solution. When there is a higher sugar concentration, more water has to be taken from the chip so the mass and length decrease, as 75% of the chip is water. Once the concentrations are balanced, osmosis does not stop, but carries on keeping the levels the same. This can be done because it is not active, and does not use energy to pass the molecules through the membrane. Evaluation To improve the accuracy of this experiment, we could have; * Weighed all of the pieces of chip separately. * We could have timed the length of the chips being in the fridge, and kept it constant, and not roughly 3 days after ...read more.

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