Chirality is a geometric property of some molecules and ions. A chiral molecule/ion is non-superimposable on its mirror image. The presence of an asymmetric carbon center is one of several structural features that induce chirality in organic and inorganic molecules.
Individual enantiomers are often designated as either right-handed or left-handed. Chirality is an essential consideration when discussing the stereochemistry in organic and inorganic chemistry. The concept is of great practical importance because most biomolecules and pharmaceuticals are chiral.
Many biologically active molecules are chiral, including the naturally occurring amino acids (the building blocks of proteins) and sugars. In biological systems, most of these compounds are of the same chirality: most amino acids are levorotatory (l) and sugars are dextrorotatory (d). Typical naturally occurring proteins are made of l-amino acids and are known as left-handed proteins; the comparably rarer d-amino acids produce right-handed proteins.