Osmosis

• Osmosis is the net movement of water molecules from an area of high concentration of water molecules to an an area of low concentration of water molecules, through a partially permeable membrane
• Isotonic solution- the number of solute are equal on both sides of the membrane. There will be no net movement
• Hypotonic- the number of solutes is lower on the outside of the cell. Water will move into the cell by osmosis. Cells mass increases
• Hypertonic- the number of solutes is higher outside of the cell. Water moves out of the cell by osmosis. The cells mass decrease
• For example, red blood cells could:

  • lose water and shrink
  • gain water, swell and burst in a more dilute solution
• Plant cell

  -Osmosis can cause the cells to become turgid whenw ater enters them. This is integral fpr maintaining plant structure

  -If water leaves the cell, it becomes flaccid and further loss of water causes plasmolysis.
• Osmosis practical

  1)Use cork borer to cut 1cm3 of section of potato then measure and record mass of potato using mass balance

  2)Put potato in test tube and add 2 cm3 of 0% solution into the beaker. Start the timer

  3)After 15 minutes, remove potato from test tube and blot the potatos dry to remove any solution using paper towel. Reweigh using mass balance and record the mass in the result table.

  4)Repeat the steps for different solution with different concentration of glucose( 10%, 20%, 30%)
• Describe how water is taken in water from the soil

  -Water is taken through the root hair cells via osmosis. Water molecules moves from an area of high concentration of water molecule to an area of low concentration of water molecule.