Can parity violation bias the homochirality of biological molecules? · revision history

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Title

Can parity violation bias the homochirality of biological molecules?

Plain

Life uses only left-handed amino acids and right-handed sugars, and the weak force slightly favors one handedness. The favoring is predicted to be extremely small, and it is unknown whether any natural chemical process could amplify it into a full preference.

Precise

Predicted $\Delta E_{\mathrm{PV}}$ for amino acids and sugars corresponds to an equilibrium enantiomeric excess of order $1e-17$ at $300\,\mathrm{K}$ (estimate). Question: does any autocatalytic amplification mechanism (Frank-type autocatalysis with mutual inhibition, Kondepudi-Nelson bifurcation, Viedma ripening) under prebiotic conditions convert a bias of this size into a probability of selecting the natural handedness measurably different from $1/2$, given statistical fluctuations of order $N^{-1/2}$ in $N$ molecules and competing chiral biases (circularly polarized light, magnetochiral effects). An answer is a model with measured rate constants and volumes giving that probability, or an experiment showing PV-directed selection.

Settled by

A calculation of the selection probability in a chemically realistic amplification network with measured parameters, together with an accurate $\Delta E_{\mathrm{PV}}$ for the relevant molecules.

Kind

phenomenon

Answer type

yes-no

References

(empty)

Literature status

contested

Status note

Theoretical estimates place the PV-induced excess near 1e-17 at 300 K; no experiment has shown PV-directed selection.

Posed since

(empty)