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Investigating the water potential of potato discs in different concentrations of sucrose solution

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Investigating the water potential of potato discs in different concentrations of sucrose solution Background knowledge Osmosis can be defined as the movement of water from an area of high water potential to an area of lower water potential through a semi permeable membrane. Osmosis only concerns the movement of water molecules compared with diffusion. Plant cells depend on water for survival and the main movement of water into plant cells is done through the process of osmosis. Plant cells take up water by osmosis and they start to swell due to the water pressure. Plant cells continue to swell until they are prevented from swelling anymore by the cell wall. ...read more.


During this process the plant loses vital water and becomes permanently damaged. Tonicity measures the ability of a solution to exert an osmotic pressure upon the membrane. Tonicity involves three solution states which include: Hypertonic, Isotonic, and Hypotonic. The table shown below briefly describes each state: Solution State Description Hypertonic Contains a high concentration of solute relative to another solution (e.g. the cell's cytoplasm). When a cell is placed in a hypertonic solution, the water diffuses out of the cell, causing the cell to shrivel. This is plasmolysis in the case of plant cells. Low water potential. Isotonic Contains the same concentration of solute as an another solution (e.g. the cell's cytoplasm). ...read more.


This is prevented from happening in the human body by a process called osmoregulation. Throughout this process the mineral salts and water content in the body are monitored and adjusted accordingly with the help of the kidneys. Water potential can be defined as the amount of water molecules contained within a particular solution. Pure water has a water potential of 0 whereas a dilute solution will have a water potential of at least -1. For instance a solution with a water potential of -340 doesn't actually contain much water, however this solution has a high solute concentration. In summary the closer the water potential is to 0 the more water contained in the solution, and the more negative the water potential the less water and a greater solute concentration. The water potential equation is shown below: Water potential = Pressure potential + Solute potential ? = ?p + ?s ...read more.

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