What are Chiral Molecules?
The atoms which make up each amino acid molecule (except glycine) can be assembled in two slightly differing molecular shapes. The difference between the two shapes is like the difference between your left and right hands. Each hand has the same components, arranged in the same way, i.e. one thumb on the side of the palm, and four fingers in a row. We could write a formula for a hand as T1F4 and this would be equally valid for each hand. But, have you ever tried putting a right hand into a left hand glove? Your two hands are not exactly the same. You cannot substitute a right hand for a left hand. Hold your right hand up to a mirror and compare the reflection in the mirror to your left hand. Your left and right hands are mirror images of one another. Amino acids (and all chiral molecules) have this same property. Each amino acid has two mirror image forms which have been called right handed and left handed. The simplest amino acid which shows this property is Alanine. Left Handed Alani
