Cell membrane transport proceses

• Diffusion (passive)


  doesn't require energy

  substances such as carbon dioxide and oxygen move the phospholipid by layer

  from high to low concentration
• Osmosis (passive)


  movement of water over a semi-permeable membrane

  requires a channel protein

  form of facilitated diffusion

  from high to low concentration
• Facilitated diffusion (passive)


  Movement with a channel or carrier protein e.g. amino acid, glucose

  from high to low concentration