Question

An amino acid that is not optically active is
A. Glycine
B. Valine
C. Isoleucine
D. Leucine

Answer 1

Hint: It is the simplest amino acid and is the only amino acid that is not optically active (it has no stereoisomers). This amino acid is essential for the biosynthesis of nucleic acids as well as of bile acids, porphyrins, creatine phosphate, and other amino acids.

Complete answer:
Proteins are the building blocks of life. They are made of small carbon compounds called amino acids. Amino acids are made up of carbon, oxygen, nitrogen, hydrogen and sometimes sulphur. All amino acids have the same general structure. Proteins are made up of a combination of about 20 amino acids. The amino acids are joined together by several covalent bonds called peptide bonds to form proteins.

The whole class of amino acids has a common framework of the organic group of carboxylic acids and a group of amino acids bound to the saturated carbon atom. Glycine is the simplest member of the amino acid group, where the saturated carbon atom is unsubstituted, thus making it optically inactive. The side chain is made up of a hydrogen atom.

Valine is present in many proteins, often in globular proteins that help to establish the three-dimensional structure. Valine, promotes mental vigor, muscle coordination and emotional calmness.

Leucine is an important, branched-chain amino acid (BCAA) necessary for muscle, skin and bone growth and repair. Leucine is thought to be the only amino acid that can promote muscle development and help reduce muscle weakening with age.

Isoleucine is one of nine essential amino acids in humans. It has numerous physiological roles, such as helping to repair wounds, detoxifying nitrogen waste, increasing immune response, and facilitating the production of multiple hormones. Required for haemoglobin production and management of blood sugar and energy levels, isoleucine is distributed in human muscle tissues.

Thus, the correct answer is option A i.e., Glycine
Note:The 20 amino acids present inside proteins represent a wide variety of chemical flexibility. The actual content of the amino acid, and the sequence, of a given protein, depends on the sequence of the bases in the gene that encodes the protein. The chemical properties of protein amino acids decide the biochemical function of proteins.