Movement of substances

• diffusion 


  movement of particles from an area of higher concentration to an area of lower concentration
• check list about movement

  what

  where to where

  how

  gradient
• example of diffusion

  oxygen moves from the blood into the cell by diffusion form higher to lower concentration
• concentration gradient affects rate of diffusion 


  steeper concentration gradient, faster ROD
• surface area to volume ratio affecting ROD 


  larger SA:V ratio

  faster ROD
• distance affecting ROD

  smaller the distance

  faster ROD
• temperature affecting ROD

  higher temperature

  faster ROD
• osmosis 


  movement of water from an area of high water potential to an area of lower water potential across a selectively permeable membrane
• plant cells- plasmolyzed

  low water potential outside the cell so water moves out of cell and becomes plasmolyzed
• plant cells- turgid 


  high water potential outside the cell so water moved in and becomes turgid

  !doesn't burst because the cell wall stops this!
• animal cells- lysing 


  high water potential outside the cell so moves in and causes the cell to burst
• animal cells - shrivel 


  low water potential outside the cell so water moves out and causes the cell to shrivel up
• active transport 


  movement of molecules from an area of low concentration to an area of high concentration using a specific carrier protein and energy in the form of ATP
• example of active transport 


  mineral ions moved by active transport from lower to higher concentration from the soil into the root hair cell using a specific carrier protein and energy in the form of ATP