Osmosis Experiment

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Osmosis Experiment Aim: To investigate the factors which affect osmosis in potatoes and to investigate one in detail. Introduction: Osmosis is the net movement of water from a high concentration to a low concentration through a semi permeable membrane. This diagram demonstrates it. In plants osmosis takes place between the cytoplasm and the solution outside of the cell. The effects of osmosis on the plant cell are visible to the eye. When a plant cell is placed in a less concentrated sugar solution the water passes through the cell wall, cell membrane and cytoplasm and into the central vacuole. The increased pressure in the central vacuole pushes out on the walls of the cell which gives the cell rigidity. When the plant cell is in this state it is known as being turgid. Sometimes plants cells can be placed in more concentrated sugar solutions, although this is unlikely in nature. If this happens the water passes out through the central vacuole, through the cytoplasm, the cell membrane and the cell wall into the solution outside the cell. This causes the pressure inside the central vacuole to decrease. The cell looks visibly deflated and limp. This state is known as plasmolysed. The solution which has a higher osmotic pressure is known as being hypotonic. If the cell is turgid the solution inside the central vacuole is hypotonic, if a cell is plasmolysed the solution outside the cell is hypotonic. There is also a stage where the concentrations of solution inside and outside the cell are equal. This is known as an isotonic state. Factors: There are many factors which could affect osmosis in potatoes, they are: · The size of the potato- a larger potato would have a larger surface area which would mean more cells are closely exposed to the sugar solution. · The type of the potato may have an effect on the rate of osmosis. · Concentration of the solution - the greater the difference in

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