| − | '''α-amino acids''' (α is the greek letter ''[[alpha]]'') have the general formula '''NH<sub>2</sub>CHRCOOH'''. There are around 20 naturally occurring α-amino acids which [[polymer|polymerise]] by [[condensation polymerisation]] to form all known [[polypeptides]] (which form the primary structure of [[proteins]]) in biological organisms during [[gene transcription]]. | + | '''α-amino acids''' (α is the greek letter ''[[alpha]]'') have the general formula '''NH<sub>2</sub>CHRCOOH'''. There are around 20 naturally occurring α-amino acids which [[polymer|polymerise]] by [[condensation polymerisation]] to form all known [[polypeptides]] (which form the primary structure of [[proteins]]) in biological organisms during [[gene translation]]. |