Question

Describe the structure and function of fatty acid molecules, including the difference between saturated and unsaturated fatty acids

Answer 1

A fatty acid has two main parts: 1) a long hydrocarbon chain and 2) a carboxylic acid group. The hydrocarbon chain is how we can tell if it is saturated or not. If there are carbons-carbon double bonds, then it would be unsaturated. Saturated fatty acids have no double bonds. 
Fatty acids are very important to the body for several reasons. They are essential to the structure of the cell membrane, they can be used for long term energy storage, healthy brain function, targeting molecules for many proteins, as well as cellular messengers. 

Answer 2

Answer: Fatty acids are fats that have acidic carboxyl groups on them. Something like CH3-(CH2)n-COOH Unsaturated fatty acids have double bonds between 1 or more of the carbons in the chain. They are unsaturated with hydrogen, but can be hydrogenated chemically. Fatty acids have many roles, but a very common one is to form the lipids in membranes. In that case two fatty acids are usually joined to phosphate plus some others.