What is an example of an amino acid without a chiral carbon?
Hint :A chiral carbon (can also be referred as asymmetric carbon) is an atom of carbon which has four different atoms or groups of atoms attached to it. Also, ‘D’ and ‘L’ are the two chiral forms of amino acid.
Complete Step By Step Answer: Amino acids are referred to as the building blocks of protein and they contain an alpha carboxyl group and an alpha amino group. The carbon which is attached to the alpha carboxyl group and the alpha amino group is called alpha carbon. Except glycine, all amino acids have four different groups that are attached to the alpha carbon. Because of which, at least one asymmetric centre (alpha carbon) is present in all amino acids and the compound with this type of arrangement is known as Chiral. Cells make amino acids using enzymes so they are always of ‘L’ configuration. Amino acids having non-polar side chains are amphipathic (also known as amphiphilic) because some part of them is hydrophobic (also known as water hating) and some part is hydrophilic (also known as water liking). Amino acids which have amine-containing side chains (names as arginine, lysine, histidine) have groups which vary in charge from $ +1 $ (proton on) to $ 0 $ (proton off). This loss of a proton from the side chain results to have no charge in the side chain. Similarly, gain of the proton results in a positive charge to the side chain. Glycine is the only amino acid with no chiral carbon (asymmetric carbon). Basically, apart from glycine, all amino acids have chiral carbon.
Note : Glycine does not contain any chiral carbon (asymmetric carbon) because it has two hydrogen atoms attached to alpha carbon. Also, there are twenty amino acids which can be found easily in proteins.