Chirality

From CreationWiki, the encyclopedia of creation science

Molecules like amino acids are chiral, meaning they exist as optical isomers of each other. A "chiral" molecule (from the Greek cheir, cheiros a hand) is one that can not be superimposed on its mirror image. Just as left and right hands are mirror images and not the same, chiral molecules have the same things attached in the same order, but opposite of each other.

The two isomeric forms (enantiomers) of amino acids are known as the D and L forms. Although most amino acids (except for glycine, which is non-chiral) can exist in both L and D forms, life on Earth is made of only L-form amino acids. The L form is found in proteins. The D form is found in only some proteins that are formed by exotic sea dwelling organisms. No one knows why this is the case, but it offers strong evidence that life was designed rather than the result of random chemical evolution.