Diffusion

• Is diffusion active or passive?


  passive
• what is the definition of diffusion?


  The net movement of particles (molecules or ions) from an area of higher concentration to an area of lower concentration

  • down a concentration gradient
• Which ways will molecules 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
• What is the CONCENTRATION GRADIENT?


  The path from an area of higher concentration to an area of lower concentration gradient. Particles diffuse DOWN a concentration gradient.
• Diffusion is a PASSIVE PROCESS. What does this mean?


  No energy is needed for it to happen
• What can particles diffuse across?


  cell membranes, as long as they can move freely through the membrane
• What is simple diffusion?


  when molecules diffuse directly through a cell membrane