Lipids
Lipids are naturally occurring organic molecules that dissolve in non-polar organic
solvents
Defined by their solubility rather than their chemical structure
Contain large hydrocarbon sections
This accounts for their solubility character
Fats & oils – most abundant lipids in nature
Triacylglycerols (triglycerides) – are triesters of glycerol with three long-chain
carboxylic acids (fatty acids)
Fatty acids – unbranched, with an even number of carbon atoms
The 3 fatty acid groups can be different
Monounsaturated – fatty acids with only one double bond
Polyunsaturated fatty acids – have more than one carbon-carbon double bond
Steroid – A lipid with tetracyclic structure
3 rings are six-membered, the 4th ring is five-membered
H
Cholesterol – most abundant animal steroid
Two important functions
Minor component of cell membranes
Cholesterol is the body’s starting material for the synthesis of all other
steroids
H
HO
H