Researchers Identify the Origins of Metabolism (phys.org) 56
An anonymous reader quotes a report from Phys.Org: A Rutgers-led study sheds light on one of the most enduring mysteries of science: How did metabolism -- the process by which life powers itself by converting energy from food into movement and growth -- begin? To answer that question, the researchers reverse-engineered a primordial protein and inserted it into a living bacterium, where it successfully powered the cell's metabolism, growth and reproduction, according to the study in Proceedings of the National Academy of Sciences. The researchers looked at a class of proteins called ferredoxins, which support metabolism in bacteria, plants and animals by moving electricity through cells. These proteins have different, complex forms in today's living things, but researchers speculate they all arose from a much simpler protein that was present in the ancestor of all life.
Similar to the ways biologists compare modern birds and reptiles to draw conclusions about their shared ancestor, the researchers compared ferredoxin molecules that are present in living things and, using computer models, designed ancestral forms that may have existed at an earlier stage in the evolution of life. That research led to their creation of a basic version of the protein -- a simple ferredoxin that is able to conduct electricity within a cell and that, over eons of evolution, could have given rise to the many types that exist today. Then, to prove their model of the ancient protein could actually support life, they inserted it into a living cell. They took the genome of E. coli bacteria, removed the gene it uses to create ferredoxin in nature, and spliced in a gene for their reverse-engineered protein. The modified E. coli colony survived and grew although more slowly than normal.
Similar to the ways biologists compare modern birds and reptiles to draw conclusions about their shared ancestor, the researchers compared ferredoxin molecules that are present in living things and, using computer models, designed ancestral forms that may have existed at an earlier stage in the evolution of life. That research led to their creation of a basic version of the protein -- a simple ferredoxin that is able to conduct electricity within a cell and that, over eons of evolution, could have given rise to the many types that exist today. Then, to prove their model of the ancient protein could actually support life, they inserted it into a living cell. They took the genome of E. coli bacteria, removed the gene it uses to create ferredoxin in nature, and spliced in a gene for their reverse-engineered protein. The modified E. coli colony survived and grew although more slowly than normal.
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how does it reverse entropy (Score:1)
i mean sure, overall the sun is blasting out entropy by the megaton/second, but what is it about the periodic table of elements that allows these complex and fragile patterns to arise locally?
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the elements are the opcodes of the universe
put enough of them together and you end up with some pretty convincing code that executes, don't you think?
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It isn't. The sun is blasting ENERGY to the earth which can be converted into complex arrangements of matter. The same way that, if you shake a cup full of dice, there is a non-zero chance of them ending up stacked on top of each other in a column. Entropy, while it will eventually kill the sun, it isn't a factor on earth because of the constant energy input.
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No, entropy is correct. The Earth radiates about the same amount of energy it receives. However, it receives that energy in a low entropy form - a few (relatively speaking) high energy photons coming from a specific direction, the sun. It radiates it as a much higher entropy form in many more directions as many more lower energy photons. More directions and more photons means more degrees of freedom, so more entropy. Life in uses this gift of low entropy energy to organize matter on Earth the way it does.
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The combination of an autocatalytic set plus an energy source is to me a very promising model for how live can arise out of abiotic soup.
https://www.the-scientist.com/... [the-scientist.com]
The autocatalytic set is a generalization of cyclic set of reactions where chemicals A and B go through a few stages and end up creating A and B again.
The idea is that as soon as you have an autocatalytic set going you have self reproduction and metabolism and you have a start of life.
The big question still remains (Score:3)
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FSM touched it with His noodly appendage, obviously.
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These would have been evolved from even simpler structures.
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It's simpler structures all the way down!
You don't (Score:1)
You don't go from a whole set of non functioning components to something which could be called working in one step, The first precursors to life where probably tied to very specific environments and where made from only a few components, by modern standers they probably did not have metabolism, may not have had cell membranes at all, may have only reproduced as individual components and so on. Any time a feature that corrected such a glaring omission happened, due to reproductive copying errors, no matter h
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the answer is that there is no such thing as "non functioning components"
your bias is wrong
all components function all the time, they do what they do notwithstanding what you *think* they *should* be doing
Re:The big question still remains (Score:4, Insightful)
How do you go from non-functioning components to the first functioning version
Well that's just it, everything has a function given enough time in the right environment. Putting atoms in proximity leads to molecules, jumbling molecules leads to proteins and continued jumbling results in self-replicating chemicals. Once it's self-replicating, it's only a matter of time before the jumbling makes something more and more complex. It's kinda like how golf-ball-sized hail is formed, it's not single cycle it's lots of cycles.
So, the answer to your question is really, "a suitable environment combined with time". Earth is our only example of a suitable environment thus far.
Creationists (Score:1)
Is that what got said? or just what you wanted to hear? once you have any form of self replicating molecule, not cell not even single metabolic pathway but molecule, it isn't chance but instead chance +replication +selection. Hand-waving at the replication and selection does not make them disappear. Like a ratchet the selection pushes the result in a single direction "more surviving offspring" which until a complete metabolism has been achieved is more complexity, since surviving with less required inputs
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I put a bunch of metal shards in a box and shook it up really hard to make a rolex argument.
Impossible. You also need to pray really hard to get that Rolex.
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Well, because a rolex is a very specific arrangement of things. Most DNA is junk, and bits and pieces of small molecules self-perpetuating don't evolve what is good but rather what is tolerable. You get bits of junk in there, and the junk turns off by methylation, and then eventually two pieces turn on that are not harmful together and that one doesn't die from it so they stay on. Sometimes the results are useful together and reproduce better.
Your "rolex" is a giant ball of scrap metal wadded together,
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If a rolex is the most stable and self-propagating arrangement of the substance then yes, the most likely thing you'll find inside after a few trillion shakes will be the rolex that the filters converge towards.
Replicating chemicals will tend to be more prevalent. No, they're not "life".
Of those, the ones that are slightly more [life-associated property] will tend to be more prevalent.
Repeat until complexity reaches desired finish or golden brown. Place the "life" boundary at reaction to stimuli or wherever
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Love that post, GZ.
What's you've stated is actually corollary to the maxim that if you make something idiot-proof, someone will make a better idiot.
This remains true, even if you simplify all the way down to sand.
The World is Running Out of Sand, and People Are Dying as a Result [slashdot.org] — 11 November 2018
Same old fallacy of the truly inert object.
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How do you go from non-functioning components to the first functioning version
Well that's just it, everything has a function given enough time in the right environment. Putting atoms in proximity leads to molecules, jumbling molecules leads to proteins and continued jumbling results in self-replicating chemicals. Once it's self-replicating, it's only a matter of time before the jumbling makes something more and more complex. It's kinda like how golf-ball-sized hail is formed, it's not single cycle it's lots of cycles.
So, the answer to your question is really, "a suitable environment combined with time". Earth is our only example of a suitable environment thus far.
"It just does" is not a theory. We have good theories on how atoms organize into molecules and how molecules can self-replicate, we have no good theory on how elf-replicating molecules turn into living-systems
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we have no good theory on how elf-replicating molecules turn into living-systems
Well just give it some thought. Some self-replicating molecules are bound to wind up generating unrelated molecular structures. Eventually, one of these seemingly extra structures actually helps the molecule replicate faster. Then one generates a different net-like structure that manages to capture the helpful molecular structure so it's able to replicate even faster. We could call this the first cell. It would have likely generated too many weird molecular structures and broken itself to bits but not
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"How do you go from non-functioning components to the first functioning version"
I don't know for sure. Nobody does. But my vision is that Earth's early (and quite inexplicable due to the hypothesized dimness of the early sun) oceans rather quickly became a watery soup of very diverse organic compounds. There are literally dozens of mechanisms known that build complex organic compounds from simpler precursors (e.g. Miller-Urey). With no living organisms to eat the stuff, all sorts of molecules appeared m
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It's not only self-replicating. It's also obtaining molecules/atoms from the environment to allow it to continue to exist.
That first molecule or tangle of molecules that wanted to continue to exist, consume components from its e
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Abiogenesis [wikipedia.org] is extremely hard to nail down for a number of factors. First, life started a LONG LONG time ago, not long after life was first possible on this planet, between 3.5 and 4.5 billion years ago, depending on the way you interpret some spikes in the side of a cliff. Earth has been doing its best to bury all of that evidence and erode it away to nothing, so direct observation of micro fossils is probably not going to get us to an answer. The other way we can get there is by comparing DNA of living
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Put 1000 dice in a tumbler and shake it until all the dice come up 6. Would take a long time, right? Now what if you had 10^15 tumblers all shaking at the same time?
Having 10^15 tumblers will make a negligible difference. 6^1000 is a ridiculously large number compared to 10^15.
If you prove that the chances of life appearing randomly is the same as a thousand dice all coming up 6, then you have basically proven intelligent design.
Re: The big question still remains (Score:2)
You seem to have missed the part where i said it took 300,000,000 years. My numbers weren't meant to be exact, i took it for granted people would understand that. It was meant to illustrate the massively parallel "dice rolling", which was itself a proxy for random combination of atoms. 10^15 atoms wouldn't even fill a shot glass, much less account for all of the coastlines and inland waters of the entire planet.
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OK, then say 10^50 (a reasonable estimate of the number of atoms in the Earth), dice rolling happens a billion times a second for 300 million years... Nope, the chances of rolling 1000 6's are still infinitesimal.
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Stop blaming being fat on other stuff (Score:1)
You eat too much while not doing physical things enough. Fix one, or both, and stop being fat.
And the more efficient model? (Score:4, Interesting)
Seems similar to what I recall reading a couple of months back, that plants aren't terribly efficient at photosynthesis because they made some evolutionary mistakes and settled for a method that was good enough, but not optimal, and we may be able to amp that up considerably.
Engineering not science (Score:1)
So some scientists did a bunch of biological engineering to modify an organism then point at what they've done and declare "science!" *sigh* They just did the equivalent of taking the engine out of an older car and putting it into a newer car. No surprise the new car didn't perform as well afterwards. And it does nothing to show where the engine comes from, it just reinforces that you need a fairly complex engineered system of some sort to start. You can modify a car to run off a steam engine, or a nuc