Can parity violation bias the homochirality of biological molecules?
In plain words
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 statement
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.
What would settle it
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.
Status in the literature
Theoretical estimates place the PV-induced excess near 1e-17 at 300 K; no experiment has shown PV-directed selection.
Related problems
- Special case of How life came to use only one molecular handedness · Parity violation is one candidate symmetry-breaking bias for biological homochirality