1.2 3

• Synthesis of a triglyceride

  Formation of ester bonds during condensation reactions between glycerol and three fatty acids
• Saturated fatty acid


  Each carbon atom is joined to the one next to it in the hydrocarbon chain by a single covalent bond
• Unsaturated fatty acid


  The carbon atoms in the hydrocarbon chain have one or more double covalent bonds
• Lipids


  • They form an integral part of all cell membranes and are also used as an energy store
  • Many plants and animals convert spare food into oils or fats to use when they are needed
• Fats


  Solids at room temperature
• Oils


  Liquids at room temperature
• Fatty acids


  • Organic chemicals that are part of fats and oils
  • Have a long hydrocarbon chain with a carboxyl group (-COOH) at one end
• Glycerol


  Propane-1,2,3-triol, an important component of triglycerides
• Formation of ester bonds


  1. Carboxyl group (-COOH) of a fatty acid and one of the hydroxyl groups (-OH) of glycerol

  2. Condensation reaction

  3. Esterification
• Monounsaturated fatty acid


  Has one double covalent bond between carbon atoms in the hydrocarbon chain
• Polyunsaturated fatty acid


  Has two or more double covalent bonds between carbon atoms in the hydrocarbon chain
• Phospholipid


  Chemical in which glycerol bonds with two fatty acids and an inorganic phosphate group
• Phospholipids


  • The lipid and the phosphate parts of the molecule give it very different properties
  • The fatty acid chains are neutral and insoluble in water
  • The phosphate head carries a small negative charge and is soluble in water
• Hydrophilic


  Dissolves readily in water
• Hydrophobic


  Will not dissolve in water
• Monolayer


  A single closely packed layer of atoms or molecules
• Micelle


  A spherical aggregate of molecules in water with hydrophobic areas in the middle and hydrophilic areas outside
• Bilayer


  A double layer of closely packed atoms or molecules
• Unit membrane


  A bilayer structure formed by phospholipids in an aqueous environment, with the hydrophobic tails in the middle and the hydrophilic heads on the outside