[spunkets]

Polarized light has nothing to do with why amino acids are all L. Any light beam would have the same effect on both configurations. Only the energy of the beam could break up the molecule, not it's polarization.

They are all L, because of template considerations. What the original template system was is not known.

[steve-b]

Polarized light has nothing to do with why amino acids are all L. Any light beam would have the same effect on both configurations.

As the original quote noted, polarized light most certainly can have different effects on L and R stereoisomers (i.e. more likely to be absorbed by, and thereby disrupt bonds in, one than the other).

One might as well assert that inserting a screw into a threaded hole will have the same result whether the screw thread direction is the same as, or opposite to, the hole thread direction.

[UCANSEE2]

They are all L, because of template considerations. What the original template system was is not known.

Maybe God is left-handed.