Diffusion

• Diffusion is the spreading out of particles resulting in an overall movement from an area of higher concentration to an area of lower concentration
• Oxygen molecules move into the cell by diffusion, and used for respiration. Therefore, carbon dioxide also moves out of the cell by diffusion.

  
• The concentration gradient is the difference in concentrations. The greater the concentration gradient, the faster diffusion takes place.
• The rate of diffusion is affected by:

  1. The concentration gradient
  2. Temperature
  3. Surface area of the cell membrane

  These are all directly proportional