Triglycerides

• what are triglycerides a type of ?

  lipid
• what do triglycerides contain?

  one molecule of glycerol with 3 fatty acids attached to it
• how are these formed?

  condensation reactions
• what do fatty acids contain?

  long tails
• what are the tails of fatty acids made of?

  hydrocarbons
• are the tails of fatty acids hydrophobic or hydrophilic?

  hydrophobic
• Hydrophobic definition?

  repel water molecules
• what is the effect of the hydrophobic tails of fatty acids?

  make lipids insoluble in water
• what varies between all lipids, what stays the same?

  • hydrocarbon tail varies
  • basic structure same
• What bond formed when a fatty acid joins to a glycerol molecule?

  ester
• what happens when the ester bond between a fatty acid and glycerol molecule is formed?


  A molecule of water is released (condensation reaction)

  • this process happens twice more to form a triglyceride
• what are triglycerides mainly used as?

  energy storage molecules
• briefly explain why triglycerides are good to be used as energy storage molecules?

  • long hydrocarbon tails contain lots of energy
  • insoluble so do not affect water potentia;
• Explain one reason why triglycerides are good as energy storage molecules?

  Long hydrocarbon tails of fatty acids contain lots of CHEMICAL ENERGY - lots of energy released when they are broken down.

  Because of these tails lipids contain twice as much energy per gram as carbs
• Explain one reason why triglycerides are good as energy storage molecules?

  • they are insoluble so do not affect water potential of the cell
  • = they do not cause water to enter cells by osmosis which would cause them to sweell
  • triglycerides clump together as insoluble droplets in cells due to their hydrophobic fatty acid tails - the tails face inwards , shielding themselves from water with their glycerol heads