lipids

• two types of lipid -

  triglycerides and phospholipids
• triglycerides formed by -

  condensation reaction between glycerol and fatty acid
• bond formed -

  ester
• r group -

  variable, and can be saturated or unsaturated
• saturated -

  no double bonds, found in animal fats
• unsaturated -

  double bonds, in plants, able to bend, dont pack tightly together so liquid at room temp
• triglyceride made of -

  3 fatty acids and a glycerol
• phospholipid made of -

  2 fatty acids, glycerol and phosphate group
• features to function - triglyceride -

  high ratio of energy storing C-H bonds to c atoms, so makes a good energy store

  low mass to energy ratio so lots of energy in little space

  large and non polar so insoluble, and doesnt affect WP

  lots of H-O atoms, so when oxidised it releases water - benefits organisms in dry environments
• feature to function - phospholipids -

  can form a bilayer

  form glycolipids with carbohydrates which are needed for cell recognition
• emulsion test -

  add 2cm sample to 2cm ethanol in a clean beaker

  shake

  add 5cm water and shake

  cloudy white means lipid present