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Author | Topic: Murchison Meteor Questions | |||||||||||||||||||||||
RAZD Member (Idle past 1405 days) Posts: 20714 From: the other end of the sidewalk Joined: |
I was then trying to find out if anhydrous reduction was equivilant to hydrolyisis. I read all kinds of papers. then I thought, 'Wait a minute... what is that other 5%?' Hydrolysis may still be an issue... After asking you about it, I then pointed out that the 95% formic acid obtained from Sigma-Aldrich is indeed 5% water. I figure you found that out before I did, since you didn't respond. Why didn't you or Percy come forward with that information? I suppose I shouldn't assume you knew... Actually I knew the acid was mixed with water, but I was not concerned about it. There is no hydrolysis in 95% formic acid, because there are no free water molecules in the 95% formic acid solution, or did you not comprehend the point in Message 175:
Sulfuric acid - Wikipedia
quote: In a "95% Sulfuric Acid" what you would actually have is an ion mixture composed of roughly
Similar reactions occur in all concentrated acids (but may be one stage instead of two), and will continue to occur until the acid has fully reacted with the water. After that water molecules will be freely available for hydrolysis of other molecules. What part about sulfuric acid being used to suck water out of fruit makes you think there would be water available for hydrolysis? Formic acid at 95% concentration is not much different: Formic acid - Wikipedia
quote: Avantor is setting science in motion for a better world | Avantor
quote: And just for clarification in case you don't have the picture yet:
The 95% formic acid is not going to be making water available to be used for hydrolysis, rather it is going to be absorbing any extra moisture it can find. Seriously Rob. Let me repeat again: you do not have any hydrolysis in the 95% formic acid extraction. The water that was mixed with the acid to stabilize it is not water in the solution that remains. Again, you fail to explain the existence of adenine, hypoxanthine and xanthine in the extract solution. Enjoy. Edited by RAZD, : safety class compare Fiocruz Genome and fight Muscular Dystrophy with Team EvC! (click) we are limited in our ability to understand by our ability to understand RebelAAmericanOZen[Deist ... to learn ... to think ... to live ... to laugh ... to share.
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RAZD Member (Idle past 1405 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Settle down Rob.
What's this from Robert shapiro?
The isolation of adenine and guanine from meteorites has been cited as evidence that these substances might have been available as "raw material" on prebiotic Earth (18). However, acid hydrolyses have been needed to release these materials, and the amounts isolated have been low (17-19).
( Just a moment... ) Don't you mean Prebiotic cytosine synthesis: A critical analysis and implications for the origin of life? The other article is not by Shapiro. This article is all about Cytosine and only has the one paragraph on adenine. You remember that the experiment involved both formic acid and hydrolysis.
That is the comparative study done and referenced by Glavin also:
It is important to emphasize that the purines identified in formic acid extracts of Murchison were not detected in water extracts [4]. This suggests that the purines are either bound to other organics, or were produced (e.g. oligomerization of HCN) during acid extraction.
And his footnote 4: [4] Stoks P. G. and ... From http://www.lpi.usra.edu/meetings/lpsc2004/pdf/1022.pdf Old stuff, Rob. Followed directly by:
quote: If you remember, this means that you might get adenine but you would not get it degrading to hypoxanthine and xanthene, you need hydrolysis to get the degrading, and you do not have hydrolysis in the half sample that we are talking about. The issue is that you cannot get both adenine AND hypoxanthine or xanthene from this process.
I am sorry to be messing with you Razd, but I simply do not understand the tone. What tone? Yours? The biggest problem Rob is that you keep going over old territory as if you haven't understood a single part of it. You chastise Percy for taking up precious posts when 50% of the posts (or more) are your repeated assertions that amount to a hill of beans. That bit about self-replicating molecules being due to an intelligent design and unnatural was a particularly amusing waste of time on your part. To repeat:
Message 119 (to Percy) The experiments on Murchison, Murray, Orgueil, and Tagish meteors show that either adenine was there on Murchison, Murray, and Orgueil, OR that the materials needed for the ready formation of adenine with a simple acid bath (similar to the extraction process) were on the Murchison, Murray, and Orgueil meteors but not on Tagish. Rob has essentially conceded this point:
Message 45 Further, IF it was formed, THEN there were still the molecules from which it was formed available for the formation of adenine.
Now that I can agree with... and
Message 65 That is true... And good evidence to support the potential of adenine undiscovered. But it still doesn't preclude the adenine from being synthesized rather than extracted. And we still don't know how the unknown material, or unique composition of substances in the meteor would affect the reactions, if at all. Material that was shown to be "adenine-phylic" enough to prevent extraction of adenine with water, and material from which, logically, the adenine was synthesized IF it did not exist as complete adenine molecules, as the extraction process chemicals (formic acid, for example) are inadequate for forming adenine on their own. Which is when you started pulling the nonsense that 5% water in the 95% concentrated formic acid could cause the degradation of adenine into hypoxanthine and xanthine.
Message 142 You still end up with these two possibilities: (1) adenine is\was present on the meteor and it is degrading into hypoxanthine, and xanthine, the extraction process also causes degradation, OR (2) adenine is produced by the extraction process -- from compounds like hypoxanthine, and xanthine -- which at the same time is degrading the adenine it just made into hypoxanthine, and xanthine ... (see any problem here?). Given the results of the three different processes noted above, I'll stick with my previous conclusions: the existence of hypoxanthine, and xanthine on the meteor can be taken as evidence that adenine used to be on the meteor in greater quantity than today; that it is extremely highly unlikely that the extraction process both synthesized and degraded adenine ... leading to the conclusion that adenine was on the meteor in the past if it is not there today. What I am saying, as I did in the OP: ... is that you haven't learned much of anything, or made a point that has not been evident from the start: Either adenine existed on the meteor OR It was easily synthesized from molecules on the meteor. In EITHER case adenine was available for pre-biotic earth. This has been established since Message 42. You in fact concede the point in Message 45 (see above) and again here:
Message 177 Can you definitively say that there was absolutely no adenine on the meteor? Can you definitively say that there was absolutely no hypoxanthine on the meteor? Can you definitively say that there was absolutely no xanthine on the meteor? Can you definitively say that these molecules were produced during the process? Of course not! So stop beating around the bush and accept the results: Either adenine existed on the meteor OR It was easily synthesized from molecules on the meteor. In EITHER case adenine was available for pre-biotic earth. Or are you going to go around the whole sturm und drang again? You're not questioning Rob, your spinning your wheels trying to find traction for a position that is not supported by the evidence (and not supportable by the evidence, because it relies on the evidence not being there). Enjoy. Edited by RAZD, : sp compare Fiocruz Genome and fight Muscular Dystrophy with Team EvC! (click) we are limited in our ability to understand by our ability to understand RebelAAmericanOZen[Deist ... to learn ... to think ... to live ... to laugh ... to share.
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RAZD Member (Idle past 1405 days) Posts: 20714 From: the other end of the sidewalk Joined: |
RAZD writes: OR It was easily synthesized from molecules on the meteor. I have no problem accepting that. That is precisely what happened as far as I can tell. If that is the case, then the discussion moves on to the problems with the atmospheric models to accomplish the synthesis. OR adenine existed on the meteor and synthesis on earth is not necessary. However, IF synthesis from HCN rings and polymers similar to hypoxanthine and xanthine in an kerogen-like organic polymer matrix that were delivered by the meteors needs to be done with an acid bath, there are many such available on the surface of the earth today -- in spite of the earth now having an oxidizing atmosphere, and so should be even less of a concern for a pre-biotic earth. From Message 14 quote: This would easily replicate what happened during the extraction process of the experiment, thus resulting in adenine being available. Piece of cake. Time to move on? Enjoy. ps -- use less keystrokes: type [qs=RAZD]quotes are easy[/qs] and it becomes:
RAZD writes: quotes are easy tip-of-the-day from your friendly neighborhood evilootionist. compare Fiocruz Genome and fight Muscular Dystrophy with Team EvC! (click) we are limited in our ability to understand by our ability to understand RebelAAmericanOZen[Deist ... to learn ... to think ... to live ... to laugh ... to share.
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RAZD Member (Idle past 1405 days) Posts: 20714 From: the other end of the sidewalk Joined: |
razd writes:
So you are having a hard time making up your mind? OR adenine existed on the meteor and synthesis on earth is not necessary. Nope, just being sure that both options are fully represented. You can't say the results are {a} or {b} now let's look at only {b} ... (wasn't that your whole point?).
Razd: This would easily replicate what happened during the extraction process of the experiment, thus resulting in adenine being available. Unfortunately the same processes that synthesize it, would hydrolyze it further. You need a near neutral pH for stability, and a great deal more adenine than we're discussing here. No, you don't need to cover the earth with adenine, you only need adenine in the right place at the right time. Once you have a life process it can produce its own (as you have observed). Apparently it took up to 1 billion years for life to form. Now we know of at least one mechanism for producing adenine.
And even if there was an explanation (which there is not), it takes more than adenine to make an organism. We've not yet even scratched the surface of this problem. That's just the way it is... There is a lot we don't know, but that does not make the task impossible. But as we have seen with the Murchison meteor there is more information every year.
Let's leave the rest for another thread. It's more than off topic here. I thought you were done: adenine available directly or indirectly due to meteor delivery from space does result in adenine on earth.
Message 1 In molbiogirl's last post of the thread she repeated the claims (that turn out to be plentiful) that adenine has been found in the Murchison meteor. I wish to challenge that claim. So what’s the deal with Murchison? In my opinion, the complex mixture of compounds and the unknowns about Murchison make quantifiable and accurate results questionable. There is much that remains a mystery. For those who have broad interest in constraining the issue and finding adenine . It’s not time to celebrate yet. Answer: adenine is available directly or indirectly due to meteor delivery from space. Enjoy. compare Fiocruz Genome and fight Muscular Dystrophy with Team EvC! (click) we are limited in our ability to understand by our ability to understand RebelAAmericanOZen[Deist ... to learn ... to think ... to live ... to laugh ... to share.
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RAZD Member (Idle past 1405 days) Posts: 20714 From: the other end of the sidewalk Joined: |
What does that have to do with adenine on the Murchison meteor?
Enjoy. compare Fiocruz Genome and fight Muscular Dystrophy with Team EvC! (click) we are limited in our ability to understand by our ability to understand RebelAAmericanOZen[Deist ... to learn ... to think ... to live ... to laugh ... to share.
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RAZD Member (Idle past 1405 days) Posts: 20714 From: the other end of the sidewalk Joined: |
If artificial synthesis of amino acids results in racemic mixtures, and the extracts of Murchison are the same. Then it lends further credence to the position that the adenine was synthesized rather than extracted. All A is BB Therefore A This is a logical fallacy Rob, because there is B that is notA. The evidence is that adenine and other prebiotic chemicals are synthesized by natural chemical processes in space, and because they are natural chemical processes like the "artificial synthesis of amino acids" they too would result in racemic mixtures. If you had said all natural non-biological chemical synthesis reactions result in racemic mixtures you would have been much closer to the truth. Did you actually read your own article where they explain this? Enjoy. ps - for the record:
You don't remember avoiding this already in my message Message 45?
(modified to provide link to msg - use "peek" to see how) I remember saying that chirality was not a big issue in Message 29. Why not start a new thread on chirality?
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RAZD Member (Idle past 1405 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Yeah, I read it for the third time after putting out here for you again. It made me realize that chiralty in amino acids has little or nothing to do with purines like adenine. That's why I said forget it in my second response a bit ago. I began to realize it was comparing apples and oranges. It may be worth discussing in another context, but not as it regards purine extractions of Murchison. So discuss it at The Recurrent Problem of Chirality. Note the purines attach to D- chiral sugar in making DNA ...
Chiralty appears to be irrelevant to Murchison extractions of adenine. So are we done here? Time for summary of positions? Enjoy. compare Fiocruz Genome and fight Muscular Dystrophy with Team EvC! (click) we are limited in our ability to understand by our ability to understand RebelAAmericanOZen[Deist ... to learn ... to think ... to live ... to laugh ... to share.
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