Question

Which of the amino acids in is/are not optically active?

Short answer

Glycine is not optically active.

Step-by-step solution

Amino acids

The organic compounds that contain both carboxylic acid and amine group (in the alpha position) are called amino acids.

If they contain a chiral carbon then they are optically active.

Define Polyamide

All chiral molecules are optically active.

Chiral molecules are most often those molecules that contain an asymmetrically substituted carbon atom.

Unlike all other amino acids, the glycine doesn't have asymmetrically substituted carbon and therefore only glycine is optically inactive.

The structure of glycine is as shown below:

Therefore, Glycine is not optically active.