diffusion

• what is diffusion in terms of a cell membrane

  the passive movement of a molecule down a concentration gradient
• what is meant by the movement down the concentration gradient


  the movement from high to low concentration
• what is meant by passive transportation

  ATP isn't required
• how does the concentration gradient affect the rate of diffusion


  The greater the concentration gradient the greater the rate of diffusion
• how does a thickness or surface affect the rate of diffusion

  the thick of the surface the long larger the distance required to move across
• how does surface area affect the rate of diffusion


  Higher surface area is more space for diffusion to occur
• what is the formula for the rate of diffusion

  surface area x difference in concentration divided by length of diffusion path
• how does the size of molecules affect the rate of diffusion

  the larger of the molecules that slower the rate of diffusion
• how does nature of diffusing molecules affect the rate of diffusion

  if the molecules are soluble in phospholipids they will diffuse faster if they are charged they will move slower
• how does temperature affect the rate of diffusion

  the higher the temperature the higher the kinetic energy and faster rate of diffusion
• what are the properties of substances transported by diffusion

  small uncharged non polar lipid soluble
• what examples of substances transported by diffusion

  oxygen carbon dioxide and vitamin a
• what is the difference between diffusion and facilitated diffusion

  in facilitated diffusion the transported molecules are charged