Lipids

• lipids are made up of carbon, hydrogen and oxygen atoms

  the main types of lipid are triglyceride and phospholipid
• triglycerides have 3 fatty acids and 1 glycerol, fatty acids bond to glycerol with a condensation reaction and forms an ester bond

  there is 3 fatty acids, so 3 ester bonds, this uses 3 molecules of water
• fatty acids can be saturated or unsaturated

  saturate - hydrocarbon chain only has single bonds between carbons

  unsaturated - hydrocarbon chain has at least 1 double bond between carbons
• phospholipids have 2 fatty acids, 1 phosphate and 1 glycerol

  2 condensation reactions to form 2 ester bonds, 2 molecules of water used

  hydrophilic head because of negative charge on phosphate

  hydrophobic tail, repels water
• triglyceride properties

  low mass so a lot can be stored without increasing mass

  doesnt affect water potential and osmosis because they are large and hydropho so insoluble

  energy store - high number of energy storing carbon-hydrogen bonds

  metabolic water source - high ratio of hydrogen to oxygen atoms, can release water if oxidised
• phospholipid properties

  polar due to 2 charged regions

  forms phospholipid bilayer - plasma membrane around cells