Phospholipids

• Phospholipids

  • Hydrophilic, polar (phosphate) head
  • Hydrophobic, non-polar (lipid) tail
  • Make membranes selectively permeable
  • Arrange themselves so polar heads point out and non-polar tails point in (micelle)
  • If there are enough they form phospholipid bilayer
  • Different membranes have different fatty acids; affect strength and flexibility
  • Hydrophobic/lipid-soluble and tiny molecules pass easily
  • Water can’t pass through easily, not hydrophobic
  • Ions, hydrophilic molecules and large molecules do not move across membranes on their own
  • Need to be transported across bilayer