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Impossible_Cookie596 OP t1_j9b651n wrote

Abstract: Molecular chirality is inherent to biology and cellular chemistry. In this report, the origin of enantiomeric selectivity is analyzed from the viewpoint of the “RNA World” model, based on the autocatalytic turnover of glyceraldehyde as a precursor for simple sugars, and in particular ribose, as promoted by the formose reaction. Coupling of formaldehyde and glycolaldehyde produces glyceraldehyde, which contains a chiral carbon center that is carried through in formation of the ribose ring. The parity non-conserving weak nuclear interaction is the only inherently handed property in nature and is herein shown to be sufficient to differentiate between two enantiomeric forms in an autocatalytic reaction performed over geologically relevant time scales, but only in the presence of catalytic metal ions such as divalent calcium or higher Z alkaline earth elements. This work details calculations of the magnitude of the effect, the impact of various geologically available metal ions, the effect of time and temperature, and their influence on chiral selection in the molecules of life. Alternative mechanisms are also considered, and a method of resolving these is proposed.


AudiieVerbum t1_j9bawoh wrote

Fun fact, those vicks inhalers you can get are straight up methamphetamine. It's just "chiralled" the other way so it doesn't do the methy things.


throwsitawayaway t1_j9dijqq wrote

It is in fact L-Meth but as mentioned due to that chirality change the substance has no recreational value whatsoever.


tornpentacle t1_j9gfuz1 wrote

Methamphetamine refers to the racemic mixture. L-methamphetamine is not methamphetamine.


baggier t1_j9caxny wrote

Probably wrong, though cant get the original article due to paywall. This has been suggested before and is not needed, any autocatalytic process with a negative feedback loop (e.g. one enantiomer inhibiting production of the other or using the other as feedstock) will end up with just one enantiomer surviving.


PM_ME_YOUR_TDs_12 t1_j9dj6h1 wrote

You are correct, but I think they’re going one step further and proposing a mechanism via a weak nuclear interaction that is non parity preserving. But I may have missed something.


bane_killgrind t1_j9e4d6k wrote

So this concept of chirality isn't adequately explained, so I'm going to give a shot at that.

Most of the visualizations we have of molecules are flat, and so they offer an incomplete picture of how they exist in real life and the texture they have. Some long molecule is likely to be bent or rotated along certain bonds because of the individual charges of the atomic components that it's made up by.

Some forces attract, and other forces repel, a position that balances those forces could be straight or very bendy.

Let's pretend a sheet of paper is some molecule. It has a side A and a side B. The stiff surface of the paper offers an internal repelling force and the edges have an attractive force. If you cut a triangle out of the sheet, (a different shape is a different molecule) the attraction in the edges pulls the cutout into a cone. But now we need to ask, is side A the outside of the cone or is side B? It could be either, and the way to describe this distinction between two otherwise identical molecules is it's chirality.


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Black_RL t1_j9fz1wn wrote

New word for me, chirality.