Question

Which amino acid is not optically active?
A. Glycine
B. Leucine
C. Isoleucine
D. Valine

Answer 1

Hint: Amino acids are very important biomolecules or compounds containing C, H, O, and N and they serve as the monomers of protein. 20 standard amino acids are connected by the peptide bond and form a long polypeptide chain called protein.

Complete Answer:
- Amino acids are the smaller unit of proteins, and protein is the functional unit central dogma of biotechnology and all the cellular processes. Amino acids are made up of four components hydrogen, carbon, nitrogen, and oxygen (serve as a building block). They have contained one R group that is also known as a side-chain group.
- Numerous functions, properties, and activity of amino acids depending on the side chain of the amino acids. So that, we can find the optically active amino acid by analyzing its R group. This R group is unique for every amino acid.
- Based on the polarity of the functional group, the amino acid can be optically active or inactive. Glycine is the simplest amino acid containing only one hydrogen group on its side chain. 20 standard amino acids are present in the peptide residue of the polypeptide chain. These 20 amino acids are linked with help of peptide bonds and form a polypeptide chain which is protein.
- Among all of these 20 amino acids, glycine is the simplest one and does not have any chiral carbon or asymmetric carbon. Amino acids like alanine, valine, leucine, isoleucine, methionine, proline, and so on possess symmetric carbon atoms. Hence these are optically active, moreover, they showed D and L stereoisomers. Except for glycine, all amino acids are optically active.

So, according to this explanation, we can say that the correct answer to this particular question is option A ‘Glycine’.

Note: Protein is a significant macromolecule that has numerous biological functions. Amino acids are building blocks of proteins, and each of those amino acids represents different properties for example glycine is not optically active while valine is optically active.