Answer:
Protein are essential in body cells for the repair of worn out tissues. Amino acid is gotten when protein is broken down under certain conditions.
All amino acids are chiral with the exception of glycine. This means they have a central carbon atom with the R-, -COOH, and -NH2 group attached to it.
Protein contain only L amino acid because the L amino acid is the only type used by cells.
The chiral carbon in L-Alanine is S-configuration and D-Alanine is R-configuration.