Biological Molecules - Lipids Flashcards
What is a triglyceride?
Glycerol with three fatty acids.
hence tri + glyc
Describe fatty acids
Fatty acid molecules have long tails of hydrocarbons.
The tails are hydrophobic so repel water molecules.
These tails also make lipids insoluble in water.
They all have the same basic structure but the hydrocarbon tail varies,
How are triglycerides formed?
A fatty acid joins to a glycerol
An ester bond (covalent) is formed and H2O is released => condensation reaction.
When this happens thrice, you get a triglyceride.
What’s the difference between fatty saturated and unsaturated fats?
Saturated fats have no double bonds in their tails.
Unsaturated do - this causes the chain to kink
Describe phospholipids
Similar to triglycerides but one of the fatty acids is replaced by a phosphate group.
Phosphate - phosphorous + oxygen
The phosphate group is hydrophillic, the fatty acid chain is hydrophobic.
Explain the function of triglycerides
the long fatty chains contain a lot of energy that can be released when they’re broken down
lipids have 2x energy of carbohydrates
they’re insoluble
they clump together in groups and droplets with the tails facing away from water
Explain the function of phospholipids
They create the bilipid layer of cell membrances
Their tails face each other and the Ph-group faces out to water
The membrane acts as the cell’s ‘skin’ barrier that helps control the inflow and outflow of substances.
Explain the emulsion test
Shake the test substance + ethanol until dissolved
Pour solution into water
Lipids are indicated as a milky solution.
