Wednesday, January 12, 2011

Sugars for life: About face! Left turn!

A friend observes this item from Science News Daily,
ScienceDaily (Jan. 7, 2011) — Certain molecules do exist in two forms which are symmetrical mirror images of each other: they are known as chiral molecules. On Earth, the chiral molecules of life, especially amino acids and sugars, exist in only one form, either left-handed or right-handed. Why is it that life has initially chosen one form over the other? [ ... ]

…has for the first time obtained an excess of left-handed molecules (and then an excess of right-handedones) under conditions that reproduce those found in interstellar space. This result therefore supports the hypothesis that the asymmetry of biological molecules on Earth has a cosmic origin.

[ ... ]

The excess, which was over 1.3%, is comparable to that measured in primitive meteorites. The researchers thus succeeded in producing, under interstellar conditions, asymmetrical molecules of life from a mixture that did not contain chiral substances. This is the first time that a scenario that explains the origin of this asymmetry has been demonstrated using an experiment that reproduces an entirely natural synthesis.
My friend sniffs, “the production of a small (1.3%) excess of one over the other ( and then the opposite result) is a crowning achievement in a field where any success of any kind is a towering feat.”

Caution is needed. One can get 1.3% in almost any direction, at least once, before the wheels fall off.