Investigating Osmosis in Potato Cells :: Papers

Investigating Osmosis in Potato Cells Planning: Aim:- To investigate the effect of different concentrations of sucrose solution, on potato cells Osmosis:- Osmosis is the passage of high water concentration through a semi-permeable membrane to a region of low water concentration, i.e. the passage of water. Explanation of osmosis For osmosis to occur there must be; semi-permeable membranes are very thin layers of material (cell membranes are semi-permeable) which allow some things to pass through them but prevent other things from passing through. Cell membranes will allow small molecules like Oxygen, water, Carbon Dioxide, etc. to pass through. Cell membranes will not allow larger molecules like Sucrose, etc. to pass through. Regions of high concentrated water are either a very dilute solution of something like sucrose or pure water. In each case there is a lot of water, there is a high concentration of water. Regions of low concentrated water are a concentrated solution of something like sucrose. In this case there is much less water. If the solution surrounding the cell has a higher water concentration than the cell, 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 cell is likely to swell up and become 'turgid'. If the solution is exactly the same water concentration as the cell there will be no 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. The cell will stay the same size. If the solution has a lower concentration of water than the cell the cell will lose water by osmosis. Again, water crosses the cell membrane in both directions, but this time more water leaves the cell than enters it. Therefore the cell will shrink and become 'flaccid' Potato plant cells:- Plant cells always have a strong cell wall covering them.