1st ESO

3rd ESO

4th ESO

Biology 2nd Baccalaureate

Index by courses



Skip navigation

3.2.1. Fatty acids

Characteristics and classification of fatty acids

The fatty acids are the basic units of saponifiable lipids, and consist of molecules consisting of a long chain hydrocarbon aliphatic type (...-CH2-CH2-CH2-...), with an even number of atoms carbon (between 8 and 24), at the end of which there is a carbon atom that constitutes a carboxyl group (-COOH), also called an acid group.

Fatty acids do not usually appear in the free state, but rather esterified as part of the phospholipids and glycolipids, molecules that constitute the lipid bilayer of all cell membranes, or in the triglycerides of adipose tissue.

Fatty acids are classified into two groups:

The essential fatty acids are those necessary for some biological functions but which can not be synthesized by the body, so they must be obtained through the diet. The only two essential fatty acids in humans are polyunsaturatedlinoleic acid and linolenic acid. From them, the body can synthesize the rest of fatty acids.

Fundamental Ideas About Fatty Acids

Fatty acids are a type of lipid characterized by:

  • Be made up of hydrocarbon chains of the aliphatic type.
  • They have an even number of carbons.
  • The last of the carbons constitutes a carboxyl group (-COOH).


Legal warning






Follow us if it has been useful to you

Biology and Geology teaching materials for Compulsory Secondary Education (ESO) and Baccalaureate students.