Lipids

• Fatty acids

  A) SATURATED

  B) UNSATURATED

  
• Triglycerides

  • MACROMOLECULES
  • one molecule of glycerol
  • three fatty acids attached to it
  • ester bonds - formed in esterification
• Ester bonds

  A) H2O

  B) GLYCEROL

  C) FATTY ACIDS

  D) TRIGLYCERIDES

  
• LIPID FUNCTIONS

  • energy source
  • energy store
  • insulation
  • protecting organs
  • waterproofing
  • membrane structure
• TRIGLYCERIDES

  • energy storage molecules
  • good storage in bacteria
  • long hydrocarbon tails contain lots of energy - released when broken down
  • insoluble - don't cause cells to swell up by osmosis
  • from insoluble droplets in cells
• Phospholipids

  • MACROMOLECULES
  • a fatty acid molecule replaced by a phosphate group
  • phosphate group is hydrophilic
  • fatty acid tails are hydrophobic

  A) PHOSPHATE

  B) POLAR

  C) NON-POLAR

  
• Phospholipids

  • form the phospholipid bilayer in cell membranes
  • centre of the membrane is hydrophobic so water soluble substances easily pass through it
• Cholesterol

  • hydrocarbon ring structure attached to a hydrocarbon tail
  • has a polar hydroxyl (OH) group
  • cholesterol helps to regulate fluidity of the cell membrane
• Cholesterol

  • small size
  • flattened shape
  • fits between phospholipid molecules in the membrane
• Cholesterol at higher temperatures

  bind to tails and pack phospholipids closely together - membrane becomes less fluid and more rigid
• Cholesterol at lower temperatures

  prevents phospholipids packing closely together - increases membrane fluidity