lipids

• Lipids have been classified as

  • Acylglycerols
  • Waxes
  • Phospholipids
  • Sphingolipids
  • Glycolipids
  • Terpenoids-lipids including carotenoids and steroids
• Acylglycerols


  One of the most important groups of lipids
• Chemical Composition of Acylglycerols


  Composed of glycerol and fatty acids. Chemically, acylglycerols can be defined as esters of fatty acids and alcohol
• Ester formation


  Alcohol + Acid -> Ester + Water
• Triacylglycerol


  The most widely spread acylglycerol, also called triglycerides or neutral lipids
• Triacylglycerol is composed of one glycerol and three fatty acids molecules
• Fatty acids


  • Contain even numbers (2-30) of carbon atoms in straight chain attached with having an acidic groups COOH (carboxylic group)
  • May be saturated (no double bonds) or unsaturated (up to 6 double bonds)
  • In animals, they are straight chains, in plants they may be branched or ringed
  • Solubility and melting points increase with increasing number of carbon atoms
• Fats


  Containing saturated fatty acids, solid at room temperature
• Oils


  Containing unsaturated fatty acids, liquid at room temperature
• Fats and oils are lighter than water and have a specific gravity of about 0.8. They are not crystalline but some can be crystallized under specific conditions