Chapter 26: Lipids

Micelles

• The salts of fatty acids have an ionic polar head group, the carboxylate and a long non-polar hydrocarbon chain.

 

non-polar hydrocarbon                    polar head

• The polar group is hydrophilic (i.e. water-loving), the non-polar portion is hydrophobic (i.e. water-hating) or lipophilic.
• As a result aqueous solutions of this type of compound tend to formed ordered aggregates such as micelles and bilayers.
• Here the polar groups are exposed to the water and the hydrocarbon portions are "buried" within the core, away from the water.
• These types of structures are important for the working of soaps and detergents, and in biology, cell membranes.