NASA's Curiosity Rover Detects Largest Organic Molecules Yet Found on Mars (nasa.gov) 33
NASA's Curiosity rover has detected the largest organic molecules ever found on Mars -- decane, undecane, and dodecane -- suggesting that complex prebiotic chemistry may have occurred in the planet's ancient lakebeds. The findings have been published in the Proceedings of the National Academy of Sciences. From a press release: Scientists probed an existing rock sample inside Curiosity's Sample Analysis at Mars (SAM) mini-lab and found the molecules decane, undecane, and dodecane. These compounds, which are made up of 10, 11, and 12 carbons, respectively, are thought to be the fragments of fatty acids that were preserved in the sample. Fatty acids are among the organic molecules that on Earth are chemical building blocks of life. Living things produce fatty acids to help form cell membranes and perform various other functions. But fatty acids also can be made without life, through chemical reactions triggered by various geological processes, including the interaction of water with minerals in hydrothermal vents.
While there's no way to confirm the source of the molecules identified, finding them at all is exciting for Curiosity's science team for a couple of reasons. Curiosity scientists had previously discovered small, simple organic molecules on Mars, but finding these larger compounds provides the first evidence that organic chemistry advanced toward the kind of complexity required for an origin of life on Mars. The new study also increases the chances that large organic molecules that can be made only in the presence of life, known as "biosignatures," could be preserved on Mars, allaying concerns that such compounds get destroyed after tens of millions of years of exposure to intense radiation and oxidation.
While there's no way to confirm the source of the molecules identified, finding them at all is exciting for Curiosity's science team for a couple of reasons. Curiosity scientists had previously discovered small, simple organic molecules on Mars, but finding these larger compounds provides the first evidence that organic chemistry advanced toward the kind of complexity required for an origin of life on Mars. The new study also increases the chances that large organic molecules that can be made only in the presence of life, known as "biosignatures," could be preserved on Mars, allaying concerns that such compounds get destroyed after tens of millions of years of exposure to intense radiation and oxidation.
Unacceptable. (Score:3, Funny)
Report for re-education.
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It's okay, DEI is gone now you can go back to using "unacceptable" terms like fatty-acids. ... Oh wait that one may be taken.
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You just gave all the Maggots erections.
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The term is "Big-boney acids". Report for re-education.
Speaking of re-education. It's "Acids with great personality."
Obesity (Score:2)
No need to explore Mars if their chicks are fat. Let's try Venus.
Life is common throughout the universe (Score:1, Funny)
Intelligent life might be rare however, it certainly seems to be the case given a cursory glance around our homeworld.
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Why, there is a bunch of intelligent life forms on Earth. Dogs and wolves, dolphins and whales, some monkeys and apes.
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But Earth evolved advanced trolls via survival of the trolliest.
On a serious note, I suspect Earth life originated on Mars because Mars grew hospitable before the Earth did because its volcanos mellowed out earlier, being a smaller planet. Then a meteorite may have later blasted that life toward Earth, when it was ready.
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Which is a universal problem with the concept of panspermia, rendering it functionally useless as a theory. By cast
Until... (Score:2)
... we figure out how life actually started - ie went from a soup of organic molecules into chemistry that could reproduce itself and evolve then its all just what-if hand waving. For all we know there could have been some very special short lived conditions on early earth that allowed it to occur. Or, alternatively its an emergency property of certain chemical conditions. We just don't know.
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Fscking auto correct - "EMERGENT property"
Re:Until... (Score:5, Funny)
I liked "emergency property". It has an air of molecules getting together and feeling like they ought to get the show on road before some other planet beats them to it.
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Ancient explorers used that water to bathe then flew away in their space ship.
Re:Until... (Score:5, Insightful)
No, it's science. Hypotheses and theories that we test by experiment and observation. This is a new observation.
What you wrote, that is just what-if hand waving.
Re:Until... (Score:4, Interesting)
... we figure out how life actually started - ie went from a soup of organic molecules into chemistry that could reproduce itself and evolve then its all just what-if hand waving.
This is helping us narrow down the range over which we have to do that handwaving. The Miller-Urey hypothesized process for how life started is simple organic molecules --> larger organic molecules --> very large organic molecules --> self-replicating organic molecules --> life. But we have now seen larger organic molecules on Mars, and amino acids in meteorites and asteroidal surface samples. So, we're narrowing down the area we need to explore.
The path from large molecules to self-replicating molecules (such as DNA or RNA) is yet to be found.
For all we know there could have been some very special short lived conditions on early earth that allowed it to occur. Or, alternatively its an emergency property of certain chemical conditions. We just don't know.
Which is why we're looking.
The jump from molecule to LUCA is ... (Score:2)
... entirely plausible and the hypothesis surrounding these topics are generally regarded as sound. Fundamental cell mechanisms as essentially the same in all of life on earth. That's a clear indicator of LUCA. The rest is likely just "emergence" of Eukarya multi-cell organisms. Perhaps even starting off by single-cells "merely" co-operating. Let's not forget that humans are living in a nano-second of life on earth and that we live in a quite very tight symbiosis with the microorganisms inside us.
Live has b
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... entirely plausible and the hypothesis surrounding these topics are generally regarded as sound.
Just a comment here that a plausible hypothesis is not the same as a confirmed hypothesis.
The jump from "molecule" to "self-replicating molecule" is the one we have yet to get a good handle on. Once you get self-replication, you get evolution by natural selection to kick in, and emergence of eukaryotic organisms is, in comparison, much better understood.
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It's a strong indicator that life on earth has a LUCA. It's not yet proof.
Perhaps the evolution from large molecules to RNA is easy, and there's really only one likely way to do it. I sure wouldn't argue that that's the case, but one needs to consider that it MIGHT be.
My personal belief is that the evolution of life from a collection of large organic molecules is strongly dependent on WHICH large organic molecules. (That seems extremely likely.) And that it's also difficult enough that we're unlikely to
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Dammit, I left out the major point. I suspect the choice of base-pair to amino acid correspondence is arbitrary.
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Very likely it's not arbitrary. The assignment of codon triples to types of amino acid (more or less hydrophobic; compactness or length of side chain) is thought unlikely to be "arbitrary" but has considerable resilience to substitutions. Flip one codon and you might get a different amino acid, but it's likely to have a similar hydrophobicity, or a similar side-chain length. For some of the commonest amino acids, flip that third ba
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IIUC, your argument is assuming the same ribosome mechanism. But the ribosome, itself, is part of the evolved machinery. I don't think we have a good idea of just how it evolved. And some experiments have shown that the selection of amino acids used can be altered. So ISTM that live that evovolved independently might will use a different selection of amino acids, and different coding systems. (Nobody seems to be suggesting alternative nucleotides, though.)
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Since it is the ribosome which does the binding onto (and so, to some degree, selection of) the base-pair triple, before offering up an amino acid monomer to the growing protein chain, that effectively means that for each triple of base pairs (codons) you need a different ribozyme and a different base-pair sequence. So that would be between 23 and 40-several different ribozymes structures and sequences. Some of the ribozymes could be insensitive to
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Or perhaps not.
The mechanism of action of RNA molecules is thought to be (well, shown to be, in plenty of cases) by the shape of a cavity in the folded RNA matching the shape of a precursor molecule. It's unlikely that there is a single molecule (RNA sequence, leaving aside the complexities of folding and elimination of water of hydration) that sufficiently-well catalyses that reaction (say, splicing
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Most strains of eukaryotes are multicellular, probably - it's harder to say "different species" with a unicellular organism than it is with, say, an insect.
While all multicellular animals are eukaryotes, a high proportion of prokaryotes spend a lot of their lives living in multicellular colonies (frequently multi-species ; often multi-genera, if those categories map well onto
Deep frier (Score:1)
My molecule is bigger than your molecule (Score:2)
So there!
Any octane? (Score:2)
decane, undecane, and dodecane
Washington State needs to tax it.
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