VPB 112: General Veterinary Biochemistry (1+1)

Introduction and function of fatty acids

FATTY ACIDS

What are fatty acids?

• Fatty acids are straight aliphatic chains with a methyl group at one end and a carboxyl group at the other end.
• They can be represented by the formula R—COOH where R is the alkyl group – CH₃ (CH₂)n (hydrocarbon chain).The hydrocarbon chain is hydrophobic and the carboxylate group is hydrophilic. Fatty acids occur primarily as esters of glycerol.
• Fatty acids are divided into
  • Short- (2 to 4 carbon atoms)
  • Medium - (6 to 10 carbon atoms) 
  • Long - (12 to 26 or more carbon atoms).
• Most fatty acids present in human cells have an even number of carbon atoms, usually between 16 and 20.
• Fatty acid may contain no double bond (saturated) or contains one or more double bonds (unsaturated). Monounsaturated fatty acids contain one double bond and polyunsaturated fatty acids contain two or more double bonds. The double bonds of fatty acids are separated by three carbon interval.
• Cyclic fatty acids are also found - For e.g., chaulmoogric acid from chaulmoogra oil, which is used for the treatment of leprosy in humans and hydnocarpic acid.

Functions of fatty acids

• They are the constituents of phospholipids and glycolipids (component of biological membranes).
• Fatty acids are fuel molecules. They are stored as triacylglycerols, which are uncharged esters of glycerol. They provide physical protection for the organ of the body.
• Fatty acid derivatives such as prostaglandins, leukotrienes and thromboxanes serve as local hormones and as a intracellular messenger in cell signaling mechanism.