# Functional Group --- A **functional group** is a specific subunit of a larger [[molecule]] that has it's own distinctive chemical properties. ## Biologically Important Functional Groups There are some fundamental functional groups that are essential to understand in biology. - [[carboxyl group]] (—COOH) is found an acidic group that is found in amino acids and fatty acids. - [[carbonyl]] (—CO) is common. - [[hydroxyl]] is highly reactive - [[amine group]] is nitrogen containing - [[phosphate group]] very important for ATP especially - [[methyl]] groups are used to protect and identify DNA - [[ketones|ketone]] ___