Question

Which one of the following statements is correct?
(a) All amino acids except lysine are optically active
(b) All amino acids are optically active
(c) All amino acids except glycine are optically active
(d) All amino acids except glutamic acids are optically
active

Answer 1

Explanation:

Only 'glycine' is optically inactive (contains two hydrogen atoms at the \alphaα-carbon) whereas all amino acids are optically active.

Answer 2

All amino acids are optically active except glycine. The correct option is (c)

Glycine is inactive because saturated carbon atoms are unsubstituted that's why glycine is optically inactive.

• Glycine is known as photogenic alpha-amino acid. This is optically inactive.

• Glycine is the simplest amino acid that has only three groups there is no fourth group so glycine is not chiral so not optically active.

• All twenty amino acids have four different groups around a central carbon atom except glycine.