Question

Protein amino acids are

• A. Laevorotatory
• B. Dextrorotatory
• C. Laevorotatory except glycine which is nonrotatory
• D. Laevorotatory except glycine which is dextrorotatory

Answer 1

The correct option is C Laevorotatory except glycine which is nonrotatory

Glycine is optically nonactive means it can not rotate plane polarised light. Glycine amino acid does not contain an asymmetric carbon atom (property of optically active compound). All amino acids except glycine are optically active and rotate plane polarised light to the left. They are laevorotatory. They have an asymmetric carbon also called chiral carbon. Thus, the correct option is C.