If you produce amino acids in a lab, the 50% are L-Form and 50% are D-Form. Now if you produce this same Amino in the same lab and apply a North Magnetic Field to it, then all the resulting aminos are L-Form (Robert O. Becker, The Body Electric).
Now the cytoplasm of a cell itself is highly negatively charged, the water inside acting as a sink of negative charge. Negative charge created a North Magnetic Field! And so the chirality of amino acids is the necessary conclusion because of the water within a cell. D-Form aminos cannot likely be sythisized in this enviroment and are not bio-active because they ccannot interfacve with the water of biological organisms!
If you have time check out the work of Gerald Pollack from the University of Washington.

They are both partly right. According to the original report (according to the textbook, according to tragicmishap in #13), the amino acids measured in the Murchison meteorite were not ones normally associated with life, thus ensuring that contamination was not a problem. This also ensured that the results are not directly applicable to the amino acids used in living organisms.

This is a minor point, but consideration must be given to the possibility that selective enzymatic breakdown might have contributed to the excess of L-amino acids that was measured. However, this is not the major problem.

The major problem is the one pointed out by Jeffrey Bada. Under ordinary circumstances, even if one starts out with all L-forms of an amino acid (except glycine, which does not have an asymmetric carbon), the amino acid will racemize over time. This effect is used in amino acid dating, with which Bada was involved for decades. Of interest, none of the four amino acids that were measured have a hydrogen on the asymmetric carbon like the amino acids found in protein have; they all have a methyl group instead. This means that they will not racemize nearly as easily as protein-forming amino acids would.

To summarize, amino acids not used in proteins were measured as having an excess of L-amino acids in one meteorite. The problem of contamination was apparently ignored, as these amino acids are not normally made by living organisms, but it is not clear whether the possible destruction of these amino acids by living organisms was considered. In any event, these amino acids should racemize much more slowly than those amino acids that form protein, and the existence of excess L-amino acids does not translate into a similar excess of L-amino acids in protein-forming amino acids.

Bres­low said ex­pe­ri­ments have confirmed that cir­cu­larly po­lar­ized light se­lec­tively de­stroys one chiral form of ami­no ac­ids over the oth­er. The re­sult is a five- to ten-per­cent ex­cess of one form, in our case, L-a­mi­no ac­ids.

I remember discussing this previously “somewhere” 2-3 years ago but couldn’t find my comments with a quick search. Anyway, from what I remember circularly polarized light produced an excess of only ~2.5 percent with the amino acid leucine. Perhaps this 5 to 10 percent is under potentially optimal conditions?

As for the rest of the article discussing Braslow’s experiment, I do not remember reading about it. Problem is that this article is lacking on solid details.

Bres­low next sim­u­lat­ed the chem­istry that he said led to the am­plifica­t­ion and eventual dom­i­nance of left-hand­ed ami­no ac­ids. He started with a five per­cent ex­cess of one form of ami­no ac­id in wa­ter and dis­solved it.

Bres­low found that the left and right-hand­ed ami­no ac­ids would bind to­geth­er as they crys­tal­lized from wa­ter. The left-right bound ami­no ac­ids left the so­lu­tion as wa­ter evap­o­rat­ed, leav­ing be­hind in­creas­ing amounts of the left-a­mi­no ac­id.

How much exactly? Now if Braslow was referring to the “wetting and drying” scenario I also remember discussing that before, as well. I’ll see what I can dig up.

EDIT:

http://www.pnas.org/cgi/conten.....05293101v1

Their theoretical model describes a dynamic system of amino acids joining and dis-joining with a free flow of energy and ingredients. In the best-case scenario, provided that all the ingredients are present in the right conditions, this system might produce about 70% of one hand in a few centuries (a value that stabilizes and does not rise higher). Even this does not form polypeptide chains, only an excess of one-hand in the amino acids. They say that the formation of the first prebiotic peptides is not a trivial problem, as free amino acids are poorly reactive (peptide bonds tend not to form in water). To solve this part of the problem, they imagine alternate wetting and drying periods and the presence of N-carboxyanhydrides to activate the amino acids. The tests required fairly high concentrations of ingredients, and specific temperature and acidity. They could not get any single-handed chains to result, but still feel their model is better than the usual direct autocatalytic reaction models, which they view as dubious in a prebiotic environment.

If this is the basis for Braslow’s comment then I can understand why he asserts the sudden “jump” I discussed in the next paragraph.

/EDIT

Even­tu­al­ly, the ami­no ac­id in ex­cess be­came ubiq­ui­tous as it was used se­lec­tively by liv­ing or­gan­isms.

That sentence seems open to interpretation. Is he saying that in his simulation that currently living organisms enforced 100% purity? Or is he saying that 100% purity was never achieved with this pre-biotic system and is simply asserting that “eventually” a genetic system would emerge along with the mechanisms for maintaining 100% purity?

I found someone else commenting on this article:

http://creationsafaris.com/cre.....#20080408a

“The Murchison Meteorite – Discovery of Extraterrestrial Handedness:
The predominance of L-amino acids in biological systems is one of life’s most intriguing features. Prebiotic syntheses of amino acids would be expected to produce equal amounst of L- and D- enantiomers. Some kind of enantiomeric selection process must have intervened to select L-amino acids over their D-counterparts as the constituents of proteins. Was it random chance that chose L- over D- isomers?
Analysis of carbon compounds – even amino acids – from extraterrestrial sources might provide deeper insights into this mystery. John Cronin and Sandra Pizzarello have examined the enantiomeric distribution of unusual amino acids obtained from the Murchison meteorite, which struck the earth on September 28, 1969, near Murchison, Australia. (By selecting unusual amino acids for their sutdies, Cronin and Pizzarello ensured that they were examining materials that were native to the meteorite and not earth-derived contaminants.) Four alpha-dialkyl amino acids – alpha-methylisoleucine, alpha-methylalloisoleucine, alpha-methylnorvaline, and isovaline – were found to have an L-enantiomeric excess of 2 to 9%.
This may be the first demonstration that a natural L-enantiomer enrichment occurs in certain cosmological environments. Could these observations be relevant to the emergence of L-enantiomers as the dominant amino acids on the earth? And, if so, could there be life elsewhere in the universe that is based upon the same amino acid handedness?”

Basically, the point is moot because these aren’t even the correct amino acids. One wonders whether they studied only non-biological amino acids because the biological ones didn’t give them any excess of one enantiomer. Generally, any time there is a problem with a materilistic worldview, someone finds a way to move the problem to the great unknown reaches of space, where anything can, does and indeed must happen. There is literally no difference between a theist’s god and an atheist’s outer space.

When I came across this post, I was initially a bit surprised, because I was under the impression that the chirality problem had been solved recently: meteorites from outer space were the source of the left-handed bias found in living things, according to this 2008 article at http://www.world-science.net/o.....rality.htm .

An extract:

“[Columbia University chemistry professor Ronald] Bres­low said amino ac­ids de­liv­ered to Earth by meteorite bom­bard­ments left us with those left-hand­ed pro­tein un­its.

“These rocks brought ‘the “seeds of chi­ral­ity,”‘ said Bres­low….

“These ‘seeds’ formed in interstellar space, pos­sibly on aster­oids as they ca­reened through space, Bres­low said. At the out­set, they have equal amounts of left and right-hand­ed ami­no ac­ids. But as these rocks soar past a type of super-dense star known as a neu­tron star, the light rays trig­ger the selec­tive de­struc­tion of one form of ami­no ac­id. The stars emit circularly po­lar­ized light — a type in which light waves are aligned togeth­er and twist like a cork­screw.

“Bres­low said ex­pe­ri­ments have confirmed that cir­cu­larly po­lar­ized light se­lec­tively de­stroys one chiral form of ami­no ac­ids over the oth­er. The re­sult is a five- to ten-per­cent ex­cess of one form, in our case, L-a­mi­no ac­ids. Ev­i­dence of this left-hand­ed ex­cess was found on the sur­faces of these meteorites, which have crashed in­to Earth even with­in the last hun­dred years, land­ing in Aus­tral­ia and Tennes­see, Bres­low added.

“Bres­low sim­u­lat­ed what oc­curred after the dust set­tled fol­low­ing a mete­or bom­bard­ment, when the ami­no ac­ids on the me­te­or mixed with the pri­mor­di­al soup. Un­der ‘cred­i­ble’ con­di­tions sim­u­lat­ing early Earth —des­ert-like tem­per­a­tures and a little bit of wa­ter — he ex­posed ami­no ac­id chem­i­cal pre­cur­sors to those ami­no ac­ids found on meteorites. Bres­low and Co­lum­bia chem­istry grad stu­dent Mindy Le­vine found that these cos­mic ami­no ac­ids could trans­fer their chi­ral­ity to sim­ple ami­no ac­ids in liv­ing things.

“Bres­low next sim­u­lat­ed the chemistry that he said led to the am­plifica­t­ion and eventual dominance of left-hand­ed ami­no acids. He started with a five percent ex­cess of one form of ami­no acid in wa­ter and dis­solved it.

Bres­low found that the left and right-hand­ed ami­no ac­ids would bind to­geth­er as they crys­tal­lized from wa­ter. The left-right bound ami­no ac­ids left the so­lu­tion as wa­ter evap­o­rat­ed, leav­ing be­hind in­creas­ing amounts of the left-a­mi­no ac­id. Even­tu­al­ly, the ami­no ac­id in excess be­came ubiq­ui­tous as it was used se­lec­tively by liv­ing or­gan­isms.

And then I came across a 2003 article entitled “Murchison’s Amino Acids: Tainted Evidence?” at http://www.astrobio.net/news/article375.html which made me wonder if Breslow really had resolved the question. Here are the key points:

“[C]hemical studies of these meteorites have often been challenged as unreliable by scientists claiming that contamination has occurred through exposure, storage, or handling. Over time, says Jeff Bada, of the Scripps Institute of Oceanography, even carefully stored meteorites gradually become contaminated…..

“Even if it can be demonstrated conclusively that Murchison contains amino acids with a slight left-handed excess, and that this excess is not due to contamination or experimental artifacts, would that explain the world of left-handed amino acids in which we live? Not necessarily…

“According to Bada, it doesn’t much matter whether the amino acids that rained down on Earth in meteorites before life began had a slight left-handed excess. Once they arrived and mixed with the environment, Bada says, commonplace chemical reactions would have erased the left-handed signature.

“As for contamination, only laboratory analysis designed to eliminate the possibility of coelution, preferably with carefully handled samples from fresh meteorite falls, is likely to settle the question to everyone’s satisfaction. As Cody notes, ‘It’s really difficult to be 100 percent definitive in this because there’s still so may unknowns. Contamination will always be an issue.’”

Well, I’m a philosopher by training, not a chemist. Would anyone care to comment? Who’s right here?

The word “weasel” has a simple probability of 1 in 26^6 of being generated on each pass, if every letter in a six character string is randomly selected each time. I estimated my program to perform the task at a rate of 2.5*10^6 iterations per second. Given these numbers, it should generate the word “weasel” on average every ~123.5 seconds.

If my search were to include upper case as well as lower case letters, the odds would increase to 1 in 52^6 requiring an average of around 7,908 seconds (2 hours ~11 minutes). This is a 64x difference for a 6 letter word.

For the entire famous weasel phrase, 23 characters excluding spaces, the difference in scope between single and double case searches is 26^23 vs 52^23, which works out to ~8.389*10^6 times greater difficulty for searching both upper and lower case.

Using my little program, the average search time for the 23 letter target phrase would be about 4.44*10^18 years, assuming all lower case letters. For both upper and lower case, we’re looking at ~3.724*10^25 years.

About how many monkeys is that?

lol Nice comment! xD

Has anybody every tried cell reanimation? I’d like to see their results.

And as I already pointed out I was referring to reading about scenarios which occur in nature, which all so far produce limited excesses like I said. This scenario you pointed out is in lab conditions.

…take a complete, dead, cell, with all the necessary proteins in place in the proper proportions and configurations, and re-initiate the cell’s living processes…

LOL Cell reanimation…19th century Darwinism brought us Frankenstein and 21st century Darwinism will bring us Frankencell. OOL researchers are the alchemists of our time.