transport in cells

• Diffusion


  The movement of molecules from an area of higher concentration to an area of lower concentration
• Particles (molecules and ions) in a liquid and a gas move continuously
• Because of this movement, particles will spread themselves evenly throughout a liquid or a gas
• If there is a situation where particles of a substance are in a higher concentration, they will move from this region to where they are in a lower concentration
• The particles will move in both directions, but there will be a net movement from high to low concentration
• The particles will end up evenly spread throughout the liquid or gas, but will continue to move
• Examples of diffusion in biological systems


  • Substances moving into and out of living cells
  • In a leaf
  • In the lungs
  • Liver cells