Osmosis

• Osmosis =?

  The diffusion of water molecules across a partially permeable membrane from an area of higher WATER POTENTIAL to an area of lower water potential
• What does an area of higher water potential have?

  Higher concentration of water molecule
• What does an area of lower water potential have?


  Lower concentration of water molecules
• What is water potential?

  The potential of water molecules to diffuse out of or into a solution
• What do all solutions have?

  A lower water potential than pure water
• When are two solutions said to be isotonic?

  If 2 solutions have the same water potential
• What does the rate of osmosis depend on?

  • Water potential gradient
  • Thickness of exchange surface
  • Surface area of exchange surface
• What happens as osmosis takes place?

  the difference in water potential on either side of the membrane decreases, so the rate of osmosis levels off over time.
• How does the rate of osmosis depend on the thickness of the exchange surface?


  Thinner exchange surface = faster rate of osmosis
• How does the rate of osmosis depend on the surface area of the exchange surface?

  The larger the surface area = faster rate of osmosis