# What is an amino acid and how do they make up proteins?

##### 1 Answer
Aug 19, 2016

Amino acids are molecules that are the building blocks of proteins.

#### Explanation:

An amino acid is a molecule (compound) that has a backbone with an amino-end $N {H}_{2}$ and an acid-end $C O O H$ (carboxyl). There are 20 amino acids that form all the proteins in the body, they differ in their side chain R (see image)

To form a peptide a few amino acids are coupled together. To form a protein a whole string of amino acids is formed and later folded.

The coupling of amino acids is a condensation reaction i.e. water is released. The image below shows this reaction. The bond between two amino acids is called a peptide bond .