diffusion

• diffusion 


  net movement of molecules or ions from an area of higher concentration to an area of lower concentration
• • Molecules will diffuse both ways, but the net movement will be to the area of lower concentration.
  • This continues until particles are evenly distributed throughout the liquid or gas.
  • The concentration gradient is the path from an area of higher concentration to an area of lower concentration. Particles diffuse down a concentration gradient.
• Diffusion is a passive process - no energy is needed for it to happen.

  Particles can diffuse across plasma membranes, as long as they can move freely through the membrane.
• the steeper the concentration gradient the faster diffusion takes place
• the higher the temperature the more kinetic energy the particles have so diffusion takes place faster
• the larger the surface area the more molecules/ions can diffuse in/out at a certain period of time
• the thicker the exchange surface the further the molecules/ions have to travel so the slower rate of diffusion