The amino acid that lacks chirality
Lysine
Leucine
Histidine
Glycine
Ans. is 'd' i.e. Glycine "The Alpha carbon of each amino acid is attached to four different chemical groups and is therefore a chiral or optically active carbon atom. Glycine is the exception because its alpha carbon has two hydrogens substituents (2 H atoms attached to alpha carbon) and is therefore optically inactive (lacks chirality). "All amino acids except glycine exists as two stereoisomers (or optical isomers or enantiomers), designated asD (dextro) &L (levo) forms.All the amino acids found in proteins are of the L-configuration*Also rememberSmallest and simplest amino acid - Glycine*Amino acid responsible for flexibility of proteins is - Glycine*
Amino Acids Basics