What is an amino acid?

Amino acids are the basic building blocks of proteins.

In chemistry, an amino acid is a molecule containing both an amine and a carboxyl group. Short polymer chains formed by joining amino acids end to end are called peptides, while long chains are called polypeptides or proteins . Inside cells, ribosomes synthesize proteins by joining amino acids end to end using mRNA molecules as templates. This process is called translation (conversion).

Not all amino acids need to occur simultaneously as building blocks in any given protein, nor in equal quantities. Proteins may also contain amino acids very different from these. In our body, amino acids arise through subsequent “differentiation” of polypeptides formed from 20 basic amino acids.

The overall error rate in protein synthesis is approximately 10−4 (one of every 10000 amino acids is inserted incorrectly). Some antibiotics act directly, and some chemotherapy drugs indirectly, by interfering with protein synthesis.