Transport Systems in Multicellular Organisms

• Multicellular organisms


  Organisms with bodies made up of more than one cell
• Multicellular organisms


  • Their bodies contain many layers of cells
  • The distance between the surface and centre of the organism is relatively long
  • The diffusion distance is too great to rely on diffusion alone
• Multicellular organisms, like humans, have bodies made up of more than one cell
• The bodies of these organisms contain many layers of cells
• The distance between the surface of the organism to its centre is relatively long
• The diffusion distance is too great to rely on diffusion alone
• Multicellular organisms


  • The distance between the surface of the organism to its centre is relatively long
  • The diffusion distance is too great to rely on diffusion alone
• Diffusion to all of the cells would take far too long
• Diffusion cannot occur at a sufficient rate to meet the needs of the organism
• Transport system


  A system that carries necessary substances around the body
• Transport systems in animals and plants

  • Circulatory system in animals
  • Vascular system in plants
• Xylem


  Moves water and mineral ions from roots to shoots
• Phloem


  Moves sugars and amino acids to where they are needed in the plant
• Humans and some plants have specialised transport systems