F4 Chapter 3 Plasma membrane

• Two main components of plasma membrane

  Phospholipid and protein
• Predict what will happen to the membrane if cholesterol is absent

  Become too fluid at normal body temperature and too permeable to dissolve substances
• Lipid-soluble substances

  Fatty acids and glycerol
• Lipid-insoluble substances

  Water, oxygen, carbon dioxide ,ions , amino acids and glucose
• Examples of passive transport

  • Simple diffusion
  • Osmosis
  • Facilitated diffusion
• Simple difussion

  • Moves from an area of high concentration to an area of low concentration.
  • Examples: oxygen, carbon dioxide and lipid-soluble
• Facilitated diffusion

  • High to low concentration gradient
  • Examples: ions and large molecules(amino acids and glucose)
• Active transport

  Requires energy in the form of ATP molecules to change the shape of the carrier protein
• Compare passive transport and active transport

  Similarities: Moves a substance across the plasma membrane

  Differences: Passive transport does not require energy while active transport requires energy