Diffusion and osmosis

• Osmosis - The movement of water molecules from a region of high water concentration to a region of low water concentration through Selectively permeable membrane

  
• Active Transport is the transport of substances against their concentration gradient using energy (ATP)
• Diffusion - the movement of molecules from a region of high concentration to a region of low concentration along a concentration gradient
• Diffusion - once the molecules become equally distributed it will reach an equilibrium
• Diffusion in and out of cells

  
• Diffusion in and out the cell - higher concentration of OXYGEN in the blood stream than the cell
• Diffusion in and out the cell - higher concentration of GLUCOSE in the bloodstream than in the cell
• Diffusion in and out the cell - Lower concentration of CARBON DIOXIDE in the bloodstream than in the cell
• Active transport - substances passes against a concentration gradient / from a low concentration to a high concentration ( REQUIRES ATP TO POWER IT )
• ATP - a form of energy
• Diffusion and Osmosis don’t require energy
• If Glucose or Oxygen is LOW OR an inhibitor of respiration is present ACTIVE TRANSPORT IS REDUCED/STOPPED
• Osmosis - water moves across a semi-permeable membrane from a dilute solution into a concentrated one until both sides are at equilibrium.
• Active transport - Iron or molecules NOT WATER (Osmosis)
• Diagram of active transport

  
• Normal Cell

  • H2o going in
  • Cell membrane fills the cell
  • TURGID (swollen/hard)


  Plasmolysed Cell

  • H2o going out
  • Cell membrane is small (shrivels up)
  • PLASMOLYSED ( constantly lose water to the surface)