Lesson 5: Functional groups

Amines and amino acids

Section 4 of 5

Amines are like ammonia, NH₃, with carbon groups in place of one or more of its hydrogens. The simplest have an -⁠NH₂ group joined to a carbon.

Methylamine, CH₃NH₂One carbon atom bonded to three hydrogen atoms and to a nitrogen atom that carries two hydrogen atoms, an -NH₂ group.HHCNHHH
Methylamine, CH₃NH₂: a methyl group joined to an -⁠NH₂ group. The name works like a branch name: methyl, then amine.

Methylamine smells like a mix of ammonia and fish. Many small amines smell fishy, and the smell of fish that is going off comes from one of them.

Amines matter far beyond smells. Your body builds its proteins from about 20 kinds of amino acids. Nearly all of them have an amine group, -⁠NH₂, and a carboxylic acid group, -⁠COOH, joined to the same carbon. That is where the name comes from. The simplest is glycine.

Glycine, C₂H₅NO₂The simplest amino acid. One carbon atom carries both an -NH₂ group and a -COOH group.HOHNCCOHHH
Glycine, the simplest amino acid: an amine group, -⁠NH₂, and a carboxylic acid group, -⁠COOH.

Quick check

Glycine, the simplest amino acid, has an -⁠NH₂ group and a -⁠COOH group. Which families do these groups come from?