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Showing results for tags 'chirality'.
Molecules in living organisms have a chiral bias -- that is, if they are not isomorphic to their mirror image, then one form will almost always be dominant over the other. E.g., glucose is a common organic molecule found in most, if not all, living things\.; but it's mirror image is virtually absent. If there is life on other worlds, it may, of course, bear little resemblance to life on Earth -- but if it resembles terrestrial life, one might expect unbalanced chiralty in molecules in the life form. Inorganic matter, not produces from living molecules, do not show unbalanced chiralty. So: If the James Webb telescope should be capable of viewing chiralty of molecules on other planets (a tall order), and if if it should spot unbalanced chiralty on another world, that would strongly suggest that there is life on that world. Attached is a .pdf of a research article on the subject. -- Saul chirality_of_biologcal_molrcules.pdf
Recently, there's been a lot of press about organic compounds found in space rocks. All organic compounds found in living things on Earth that have chirality (i.e., that are such that the mirror image of the molecule cannot be moved onto the original molecule by a distance preserving mapping of 3-space), always show up as the L- (or left) version. This asymmetric chirality of living organic molecules, if I remember correctly, gradually ends when the organism dies -- the L-molecules gradually morph into a mixture that's half D- and half L. https://en.wikipedia.org/wiki/Chirality#Biology A recent article in Science News notes that all of the basic amino acids have been found in space rocks. My question: Have any amino acids from space had more of the left version, right version -- or did they all have L- and D- balanced versions? All of the basic amino acids are chiral. My guess: Amino acids found in space rocks have equal amounts of the D- and L- versions of the amino acids. (Reason: It must have taken a long time for these rocks to hit earth -- and dead organics morph, in time, to equal amounts of D- and L- forms.) So it seems very unlikely to me that life on Earth evolved from organics that hit Earth in space rocks. What do you think? (I think the chirality of living Earth molecules is one of the puzzles of life -- how did this happen, IMO, undoubtedly here on Earth.) -- Saul