I've already explained this to you.
And we agreed that evolution could produce homochirality, so automatically then we agreed both chiral forms organisms were already assembled by abiogenesis, and were "fighting" for resources. Therefore, chirality is not a factor in abiogenesis, and is explained by evolution. It's only later you came up with this assumption that abiogenesis requires some special proportion of left and right handed amino acids to lift off. These two are contradicting theories, pick one. I say it's evolution and it's pretty sound theory, do you wish to disagree now after we have already agreed on it before?
No, only when we start off with an excess of left handed amino acids to begin with, even then, it may not be the best answer.
You are talking about RNA and DNA, those are very refined products of millions of years of evolution. They shed off their resilience to bi-chirality in favor of other functions, but replicating molecules in organisms at the very beginnings of abiogenesis were far more robust or indifferent about it, naturally.
And what if right handed amino acid based life arose before lefthanded?
Sure, why not, indeed. That's much more sound than to assume abiogenesis couldn't have started without some special ratio, when we know both chiral forms are equally stable and reactive. They are just toxic to each other, so they did something about it. There was either "war" or "symbiosis", or perhaps more likely there was both, a little bit of making war, and then a little bit of making love, then war again, and so on, as usual.
No, proteins are broken into amino acids and other contituents then absorbed or excreted as required.
But organisms grow, new proteins must come from somewhere. So why would it need to come already assembled from the environment, why couldn't have those organisms assemble their own amino acids from simple non-chiral molecules? -- By the way, what is counterpart for protein in plants? How far is grass DNA from human DNA?
There are these funny things called emergent properties that molecules have that are not present when we consider the individual atom. The example I gave - n-butanol versus tert-butanol. They have all of the same atoms, they're just just arranged differently so have different emergent properties and different chemistry. Same with the difference between D-thalidomide, and L-thalidomide - they have all the same atoms, but arranged differently, and so they have different emergent properties as a molecule.
Yes, but can you say those emergent properties are anything but a direct consequence of what is going on a smaller scale? Can those "collective" emergent properties do anything else but that which is defined by interaction between electrons and protons and whatever else is within atoms themselves? Can those emergent properties possibly function independently of the function of their parts?