3.1.3 Lipids Flashcards
How is a triglyceride formed
Condensation reaction
What is within the structure of a triglyceride
3 fatty acids
1 glycerol
What does a condensation reaction between glycerol and fatty acids form
Ester bond
Elimination of water
How is a phospholipid formed
Condensation reaction
What is the structure of a phospholipid - what group does it contain
1 glycerol
2 fatty acids
1 phosphate group
Describe the test for lipids
Emulsion:
Add ethanol to a sample and shake
Then add water
If white emulsion forms - lipid is present
Phospholipid structure
Amphipathic (polar head, attracts water and non-polar tails, repels water)
Triglyceride structure
Low oxygen content (many C-H groups)
Hydrophobic (non-polar fatty acids)
Non-polar, cannot become charged (lose electrons)
How does being amphipathic relate to function (phospholipid)
Form bilayers - inner cell membranes
How does having a low oxygen content relate to function (triglyceride)
High energy content (lots of bonds to oxidise) so good respiratory substrate
How is being hydrophobic relate to function (Triglyceride)
Waterproofing
How does being non-polar relate to function (Triglyceride)
Poor electrical and thermal conductor - insulating
What is the structure of an unsaturated fatty acid
Kink in them - rather than being straight chained
How does being kinked benefit the fatty aid
one or more double bonds in hydrocarbon chains = kinks + prevent the molecules from packing closely together. Benefits:
Increasing Fluidity: reduce the tight packing of fatty acids, increasing fluidity of cell membranes. Maintaining membrane flexibility + function.
Lowering Melting Point: Can’t pack as tightly, unsaturated fats usually liquid at room temp.
