Triglycerides & Phospholipids

• What type of bond is formed in the condensation reaction that forms a triglyceride?

  Ester bond
• What is a saturated fatty acid?

  The hydrocarbon chain has only single bonds between carbons.
• What is an unsaturated fatty acid?

  the hydrocarbon chain consists of at least one double bond between carbons
• How does triglyceride structure relate to its properties?

  • Large ratio of energy storing C-H bonds compared to C atoms -> a lot of energy is stored in the molecule
  • High ratio of H:O atoms -> act as a metabolic water source (can release water if they are oxidised)
  • Do not affect WP and osmosis -> too large and hydrophobic, so insoluble
  • A relatively low mass -> a lot can be stored without increasing the mass and preventing movement
• What property does the phosphate head have?

  Hydrophilic
• What property does the fatty acid chain have?

  Hydrophobic
• How do phospholipids arrange themselves in an aqueous environment?

  • Hydrophilic heads face outwards, towards the water
  • Hydrophobic tails face inwards, away from the water
• What property of the cell membrane does the phospholipid bilayer ensure?

  Ensures the membrane is selectively permeable
• Complete the following about triglycerides.

  • Formed by the condensation of one molecule of glycerol and three molecules of fatty acids
  • forming 3 ester bonds
• Complete the following about phospholipids.

  • Formed by the condensation of one molecule of glycerol and two molecules of fatty acid
  • held by two ester bonds
  • a phosphate group is attached to the glycerol