Water potential and osmosis

• The potential for water to move out of a solution by osmosis

  Water potential
• The value of water potential for pure water

  0
• Solutions have a lower water potential than water because ...

  They have a lower proportion of water molecules
• What is generated by the resistance of the inelastic cell wall when water passes into the cell pushing the vacuole and cytoplasm outwards

  Pressure potential
• If the water potential of the external solution is lower than the solution inside the cell ...

  water flows out of the cell by osmosis
• The cell is hypertonic when the ...

  water potential of the external solution is lower than the solution inside the cell
• When a cell loses water it shrinks, and the cytoplasm of a plant cell will draw away from the cell wall, this is known as ...

  plasmolysis
• When plasmolysis is complete the cell is said to be ...

  flaccid
• The point at which the cell membrane just begins to move away from the cell wall is known as ...

  incipient plasmolysis
• When the water potential of the solution is higher than the solution inside the cell ...

  water will move into the cell by osmosis
• The cell is hypotonic when ...

  water potential of solution is higher than the water potential inside the cell
• When the pressure potential is equal and opposite to the solute potential the cell is ...

  turgid
• In a tissue sample, the concentration of a solution where 50% of cells are plasmolysed is taken as the point of ...

  incipient plasmolysis
• When the water potential outside the cell is equal to that inside the cell and there is no net movement of water the cell is ...

  isotonic