structure and function of triglyceride, phospholipid and cholestrol


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  • Created by: Maryan
  • Created on: 31-01-12 22:21

Triglycerides (Q)

Triglycerides: Fatty acid

  • Made up of  1 molecule of glycerol with 3 hydrocarbon tails attached.(insoluble)
  • The hydrocarbon tails are hydrophobic (water hating) and are also insoluble in water                                                  
  • The same basic structure but the tail varies 


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Phospholipids (Q)


  • Similar to triglycerides but one hydrocarbon tail is replaced by a phosphate group.
  • The phosphate head is polar so it attracts water molecules.


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Cholestrol (Q)


  • Has a hydrocarbon ring structure attached to a hydrocarbon tail
  • Hydrocarbon ring has a hydroxyl group attached to it (OH) this makes it polar and soluble.(
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How their structure relates to their function (Q)

Triglycerides: mainly used for energy storage

  • The long hydrocarbon tails have a lot of chemical energy. Its released when theyre broken down.

Phospholipids: Controls what goes in and out of the cell by making up the bilayer.

  • centre of bilayer is hydrophobic water soluble substances cant easily pass through so it acts as a barrier. The phospholipids move around to make it hard for other substances to get through e.g ions.


  • Helps strengthen cell membrane by stabilizing the rigidity of it and interacting with the phospholipid bilayer.
  • Bind to hydrophoboc tails- tails pack more closely together.
  • So the membrane becomes less fluid
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Quick questions!

  • Describe the structure and function of a triglyceride
  • How many hydrocarbon tails does it have?
  • is it soluble or insoluble?
  • What is the basic structure like?
  • Describe the structure and function of a phospholipid
  • Is the phosphate group polar or non polar, what does this do?
  • Is it soluble or non soluble?
  • Describe the structure and function of a cholestrol
  • where is it positioned?
  • what does it do to the membrane?
  • what special group is attached to the ring?
  • is it polar or non polar
  • soluble or non soluble
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