Understanding Lipid Structure: Isoprene & Fatty Acid Based Lipids

Lipids are classified into two groups according to their chemical structures: isoprene-based and fatty acid-based. Fatty acids are saturated or unsaturated monocarboxylic acids.

Fatty Acid-Based Lipids

• Fatty acids are made of a carboxylic acid group that also contains an unbranched hydrocarbon chain. The structure of fatty acid is one of the most basic varieties of biological lipids.

Hydrophobic and Hydrophilic Ends

• Unique arrangement of fatty acids provides the molecule with a non-polar hydrophobic end, insoluble in water, and a polar hydrophilic end, soluble in water.

Saturated and Unsaturated Fatty Acids

• Fatty acid is called unsaturated when there are double bonds between carbon atoms, and the fatty acid is called saturated when there are no double bonds between carbon atoms. Natural unsaturated fatty acids normally contain one to six double bonds. These double bonds are separated by two single bonds.

Isoprene-Based Structure

• Isoprene is a branched five-carbon chain. Isoprene is a liquid and flammable unsaturated hydrocarbon.

Source of Isoprene

• A broad spectrum of naturally occurring isoprene lipids is obtained from the union of isoprene monomer units such as steroids (i.e., estrogen, testosterone and cholesterol), beta-carotene, terpenes, carvone and pinene.