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02-24-2003, 01:23 PM | #1 |
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Non-organic origins of Life
The prevailing theory for the origin of life is the one of the prebiotic soup. Earth's oceans harbored simple organic chemicals (The ones Stanely Miller produced in his famous experiment) which polymerized and miraculously formed life as we know it.
Of course, the steps from simple molecules to cells are incredibly numerous, long, and complex. There are a few theories that suggest how life arizes on a lifeless array of molecules following self organizing laws. Still however, the origins of organic macromolecules are a mystery themselves. DNA, RNA, and proteins are too complex of molecules to have arisen by a simple process. Some people have suggested that non-organic (namely silicates) molecules have began the process of self organization early in the planets history. Their interaction has paved the way for organic molecules to emerge and subsequently form life as we know it. |
02-24-2003, 04:08 PM | #2 |
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Origin of Life in "Cells" of Rock? was a recent thread that had a similar subject.
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02-25-2003, 01:52 AM | #3 | |
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Nucleic acid bases, amino acids and sugars have all been synthesized in supposed prebiotic conditions (ref: Voet and Voet Biochemistry). Given time, suitable conditions - current theories favour cold over heat, to slow down the rate hydrolysis of the reacting compounds to less than the rate of synthesis - you will have a mixture that includes everything you need for that first RNA molecule to be formed. And the rest, as they say, is natural history. |
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02-25-2003, 03:46 AM | #4 |
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natural history????
what kind of chemistry is that of natural history? DNA and RNA have never been shown to be the result of natural history. Your reference is most probably Stanely Miller's experiment, which really didn't show anything but the de novo synthesis of bases, amino acids, and sugars... Anyway, I will get you the references when I have time |
02-25-2003, 03:53 AM | #5 | |
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02-25-2003, 03:55 AM | #6 |
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There's a geezer from Glasgow University, surname Cairns-Smith IIRC, who proposed the first reproducing molecules were based on slate. No doubt a Google search will yield stuff of interest. His theory only goes so far, but it is an interesting idea.
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02-25-2003, 05:02 AM | #7 |
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Alas, I fear my pun may have gone amiss...
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02-25-2003, 07:48 AM | #8 |
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Oxymoron,
The de novo synthesis of RNA has never been observed. Neither in nabulae nor on comets. And even you reach the first RNA molecule, why would I be convinced that this is anywhere close to life? Of all the in vitro selection experiments in the laboratory, not a single self-organizing population of molecules has been observed. I still think that the RNA world hypothesis is the most convincing, however it needs alot of broadening and further experimentation to shed lights on the missing parts |
02-25-2003, 08:19 AM | #9 | |
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I was only referring to amino acids. As far as RNA is concerned, some other scaffold is required. |
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