Fatty Acids
Definition and meaning of Fatty Acids in chemistry.
Fatty acids are carboxylic acids with a long, unbranched hydrocarbon chain (typically 4 to 28 carbons) ending in a -COOH group. They serve as the primary building blocks of lipids, including triglycerides and phospholipids.
In more detail
Fatty acids are classified as saturated (only C-C single bonds) or unsaturated (one or more C=C double bonds, usually in the cis configuration in nature). Saturated chains pack tightly in a straight line, giving fats like butter a solid texture at room temperature, while the kinks introduced by cis double bonds prevent tight packing, keeping unsaturated fatty acids liquid as oils. In the body, three fatty acids esterified to a glycerol backbone form a triglyceride, the main form of stored energy, while two fatty acids plus a phosphate group attached to glycerol form the phospholipids that make up cell membranes.
Key facts
| Field | Biochemistry |
|---|---|
| General formula | CH3(CH2)nCOOH |
| Functional group | Carboxylic acid (-COOH) |
| Example | Oleic acid, C18H34O2 |
Oleic acid, CH3(CH2)7CH=CH(CH2)7COOH, is a monounsaturated omega-9 fatty acid with one cis double bond; it is the major fatty acid in olive oil.
Frequently asked questions
What is the difference between saturated and unsaturated fatty acids?
Saturated fatty acids contain only single bonds between carbon atoms, while unsaturated fatty acids have one (monounsaturated) or more (polyunsaturated) carbon-carbon double bonds, which are typically in the cis configuration in naturally occurring fats.
What are essential fatty acids?
Essential fatty acids, such as linoleic acid (omega-6) and alpha-linolenic acid (omega-3), cannot be synthesized by the human body and must be obtained from the diet.