diffusion

• Diffusion


  The particles moving resulting in a overall movement from an area of higher concentration to an area of lower concentration
• Molecules that move in and out of cells by diffusion

  • Oxygen
  • Carbon dioxide
  • Urea
• Cells need oxygen for respiration


  Oxygen moves into the cell by diffusion
• Respiration produces carbon dioxide


  Carbon dioxide moves out of the cell by diffusion
• Urea is a waste product produced inside cells


  Urea diffuses out of the cells into the blood plasma
• Factors affecting the rate of diffusion


  • concentration gradient
  • Temperature
  • Surface area
• Greater concentration gradient

  Faster diffusion
• Higher temperature


  Greater rate of diffusion
• Larger surface area of the cell membrane


  Greater rate of diffusion