Osmosis

HideShow resource information
View mindmap
  • Osmosis
    • What Is It?
      • Type of diffusion
      • Movement of water molecules across a partially permeable membrane.
      • Goes from a high concentration to a low concentration.
    • Partially Permeable Membrane
      • Membrane with very small holes
      • Only let's tiny molecules such as water pass through.
      • Big molecules can't pass through (e.g. Sucrose)
    • What Happens?
      • Water molecules pass both ways through the membrane. This is because they move about randomly all the time.
      • More water molecules on one side so steady net flow of water in to the region with fewer water molecules.
      • The stronger the solution becomes more dilute as the water is trying to "even up" the concentration of the solutions on both sides of the membrane.
    • What Happens In Cells?
      • Tissue fluid surrounds the cells in the body.
      • Tissue fluid will usually have a different  concentration to the fluid inside the cells. This means water will move in to or out of the cell.
      • If the cell is short of water it is more concentrated which means the outside is more dilute so water will go in to the cell.
        • This makes the cell increase in size.
      • If the cell has lots of water it is more dilute which means the outside is more concentrated so water will be drawn out of the cell.
        • This makes the cell decrease in size.
    • Other Information
      • Tissue fluid is water with oxygen, glucose and stuff dissolved in it. It is squeezed out of the blood capillaries to supply the cells with everything they need.
      • An experiment you can do to show osmosis is cut up potato cylinders and measure them and put  some in a beaker of pure water and some in a beaker with a lot of sugar mixed with water. Leave it for about half an hour and measure them again.
        • The one in pure water should have increased in size and the one in the sugar solution should have decreased in size.

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Exchange of materials resources »