Facilitated

• What does facilitated diffusion use?


  • Carrier proteins
  • Protein channe;s
• What would some larger molecules do?

  Diffuse very slowly through the phospholipid bilayer because they are so BIG
• Which larger molecules would diffuse very slowly through the bilayer?

  examples) Amino acids, glucose
• what does facilitated diffusion involve?

  The roles of carrier proteins and channel proteins
• Give examples of charged particles?

  ions and polar molecules
• What would charged particles do?

  Diffuse slowly
• Why would charged particles diffuse SLOWLY?

  Because they are water soluble and the centre of the bilayer is hydrophobic
• How do large or charged particles diffuse ?

  Through carrier proteins/ channel proteins on the membrane

  • = facilitated diffusion
• How do molecules undergoing facilitated diffusion move?

  Down a concentration gradient - from a higher to lower concentration
• What type of process is facilitated diffusion?

  passive - does not require energy
• is facilitated diffusion and active or passive process?

  Passive
• What do CARRIER PROTEINS do?

  Move large molecules across membranes, down their concentration gradient

  • different carrier proteins used for different molecules
• How do carrier proteins work?

  1. A large molecule attaches to a carrier protein in the membrane
  2. The protein changes shape
  3. This releases the molecule on the opposite side of the membrane
• How do channel proteins work?


  They form pores in the membrane for charged particles to diffuse through , down their concentration gradient
• What do different channel proteins do?

  facilitate the diffusion of different charged particled