The Recurrent Problem of Chirality

>Life cannnot begin or proceed using racemic mixtures of the two >forms for life molecules.Life could have began using D-amino acids. It did not. The fact that all living organisms use L-amino acids is very strong evidence of common descent.>More importantly perhaps is the fact that it is only the three >dimensional aspect of the molecules and their coiled shape in the >double helix of the DNA that enables them to store the information >contained in the "genetic code" sequences non-linearly rather than >linearly in two dimensions.I don't think you understand the concept of "handedness" in biological molecules. Nor do you understand the structure of DNA. DNA is not made of amino acids in either form. DNA consists of nucleotides.

I was responding to the Evopeach. He's been running from me for a while. I didn't know the mechanics of identifying others quotes. Radz got me straight.

Then you might want to elaborate on the point you're trying to make. How about explaining your point as well as pointing out any of my text that you take issue with.
Are you saying that the exclusive use of one form of amino acid is not evidence of common descent? If you why not?

It absolutely matters in Darwin's case. The pathways required for replication, trancription, translation, and expression will not work using amino acids of opposite "handedness."
It could have began with both forms, but there is no evidence of this. Only the L forms are used.It doesn't make one iota of a difference what your "thought" is, if you have absolutely no evidence to support it.

He emailed me a few times after I joined a certain Yahoo group spouting off nonsense about how evolution violates the 2nd Law of Thermodynamics.

So, you reacted without any evidence to support your claim?
Central Dogma of Molecular Biology:
DNA RNA -> Protein
There is one path back in time. Unless, you can provide evidence of another. I won't hold my breath on that.

Again, it does not matter what you believe. D-amino acids are not interchangeable in biological sysytems. Do you have any evidence that they are? Any peer-reviewed articles?
Pick up a book on molecular biology. The "handedness" of biological molecules are vital for every fundamental process. The fact that all organisms use the L-form is evidence of common descent via DNA.

The evidence does not support this view. The common use of L-amino acids is due to the conservation of fundamental processes such as replication, transcription, translation, expression, and metabolism. It is due to the conservation of the genetic code. Besides the 3 stop codons, all of the rest code for L-amino acids. The use of D-amino acids would have required a different code, resulting in mirrored pathways, let alone left-handed B-DNA (which would presumably be needed for an L-amino proteome). The homology between genomes observed using tools of bioinformatics supports this view.

I did not say this and I do not mean that. There are 64 available codons in the genetic code. 3 of them are used as stop codons. We have 20 amino acids that they code for. All are of the L-form. That leaves 41 available codons that could have been used for D-forms, yet they are not. The remainder are used as redundant codons for the 20 L-amino acids.
You would would be hard pressed to find a statistical test that would indicate that this (0 in 41 samples) is not a significant difference.
Your argument has no validity. Until you can produce any evidence to the contrary, my statement is based on fact and is not based on belief and is accurate as written.
I find it interesting that non-specialists frequently feel that they have gained a special insight into a fundamental processes that educated, experienced professionals have somehow missed. This takes a special brand of arrogance.

I thought Peach's last post was more recent than that. My bad.
We've exchanged emails and he never reponds to specific points, always changing the subject.
Here is a brief list of his greatest claims off the top of my head:
1) The only energy the Earth receives from the Sun is in the form of heat.
He somehow has missed the change in the visible spectrum resulting in days and nights. Or, he does not attribute this energy to the Sun.
2) That the Earth is a closed system.
Yet, he concedes above that the Earth at least receives heat from the Sun which indicates by his admission that it is an open system.
3) That point mutations are 99.99% lethal.
Well, only 3 of the 64 codons are stop codons, and SNPs in the third position of the codon usually result in silent mutations (coding for the same amino acid) due to the degenerate nature of the genetic code. Also, many SNPs result in missense mutations that insert an amino acid with similar properties such as polar for polar. i.e.- a switch from serine (TCT) to threonine (ACT).
How he can get 99.99% is anyone's guess.

Should I restate my replies to you in language that is easier for you to understand? Would that make it easier for you to respond? You evidently do not, since you comment on things that you know absolutely nothing about.
Perhaps you should spend some time studying the fundamentals of molecular biology and biochemistry before running off at the mouth like this.

Brilliant. In other words, you have no idea of what you are talking about and you have no evidence to support what you say.
Thanks for playing.
By the way, the exclusive use of one form or the other is a necessity. They are not interchangeable. There would be some remnants of this in genomes if this were the case. There are not.

Let me fill you in. I'm a molecular biologist that makes bacterial protein expression clones for a living. I am an expert in this area.
You have no idea what you are talking about. You lack even the basic understanding of the molecular process to discuss it intelligently.
Science does not give the slightest crap about what you think. Nor does it care about your worthless mathmatical models (worthless because you fail to understand that similarities across genomes are indicative of common descent, thus the proteome is evidence of common descent). Once the process began it could not back up and reboot. The first transcription of RNA into protein would have been mediated by the first RNA polymerase. This would be like a bouncer at the door deciding who could get in. The L-aminos were admitted.
Sell your philosophical bullshit to someone whose buying. I ask again: Do you have any evidence that D-amino acids were ever part of any organisms proteome?
Look into this subject seriously and I'll can the sarcasm.

What the #*%&! The fields of force? Are you serious? What exactly is this extrachromosomal material you speak of? Umm, that's what I do. There is absolutely no use of D-amino acids in biological systems. The genetic code is proof of this. I'll tell you what, name which codon signals a D-amino acid? Which tRNA? Do us one better and make a prediction based on your hypothesis please.

This guy is as bad as a creationist, he just leans to the other side. To him no evidence is no problem. A little bit of knowledge is a dangerous thing.
How's life in Columbia? I'm in KC.