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Is Brownian Motion The Secret Of Life After All?
mindpixel writes: "unisci is reporting research from Georga Tech that suggest the the key motor protein ATP works by 'rectified browian motion' as a kind of thermally driven nano-ratchet. The researchers said "We're arguing that Brown really had discovered the secret of life ... When you get into this sub-cellular level on the nanometer scale, the dynamics and vitality of protein molecules is really due to thermal motion." The implications for nanotech are obvious."
I am a biochemist with over 30 years of research experience in enzymology, including ATP-utilizing enzymes. While Brownian motion and diffusion processes are both important and interesting, and these researchers have clearly performed some significant experimentation, the statements contained in the linked article implying that Brownian motion constitutes the BASIS of life can only be described (charitably) as overreaching. Actually, I expect that the expressions (as written) are those of the journalist, and not the precise views of the researchers.
I was afraid I wouldn't be able to understand the article because it contained organic-chemistry vocab words, but it's not as complex as the writeup led me to believe.
I'm no molecular researcher, but I'm glad to hear of these discoveries being made on the boundary where quantum mechanics and classical physics meet--I think it is where we'll finally come to understand the fundamental interconnectedness of all things.
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I don't know about "secret of life" stuff, but I do find this article to be damnably cool. We (living stuff) take a random series of interactions, and act on them as if we perceived some pattern in them, all the while lacking the mental capacities to perceive such a pattern. Sure, natural selection suggests that anything that acts as if it had perceived this pattern will outbreed and thus outsurvive anything that doesn't, so long as this pattern facilitates reproduction, but actually identifying this pattern (why the seemingly random Brownian motion actually produces recognizable pattern of acceptable interactions) is kind of neat. It's like watching a Foucault pendulum in action for the first time: anyone can explain the theory behind it (in this case, natural selection), but there's still something indescribable about watching the blocks of wood fall (ATP moving along microtubule).
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Therefore it is not brownian motion directly, but osmosis that powers all life.
I think you are envisioning a concentration gradient. Although osmosis, being the dilution of a solution by a pure solvent, is its own way a concentration gradient. And what's the driving force for concentration gradients to flatten out? ENTROPY. Therefore, entropy powers all life. (Entropy will also kill the universe, which is what drove Boltzmann to suidice after realizing the eventual "heat death" of the universe.)
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ATP isn't a protein at all. The "motor protein" they're talking about is kinesin. The original article's got it right, of course.
They even proved, that you cannot rectify random events like that (i think they calculated using random photons or something..) as this would create the beforementioned perpetum mobile.
Thus as far as saying, that this motor-protein uses brownian motion is wrong. In order to generate motion you have to utilize a energy-releasing reaction (e.g converting ATP to ADP). Some others got it ringt as they described how a surplus of protons is used as driving force.
That thermal motion is improtant, is no surprise though, all reactions (almost) require an activation energy to occour (even decomposition of nitroglycerin, although it is small indeed).
The discovery of this motor protein and how it works by converting a chemical gradient to mechanical work, is interesting however.
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Interestingly, ATPase is a nano-scale rotor/generator. There are some great movies of the proposed operation from a berkley server. The ATP synthase motor is driven by the flow of protons from an area of high to a low concentration. Therefore it is not brownian motion directly, but osmosis that powers all life.
biobox
Robert Brown didn't discover the secret of life. He simply observed and identified what we now call Brownian motion; he did not go far in mathematically developing his discovery. Einstein and Desaulx were the ones who truly quantified and detailed Brownian motion, I think that they are the ones who truly deserve the credit for "discovering the essence of life", if any credit is due.
Oh that's the answer to the ultimate question... my bad.
Seriously though, this reminds me slightly of soda constructor (which, if you haven't checked out, do so now, do not pass go, do not collect 200, yada yada) The idea being that a small amount of random (or in soda's case, rhythmic) motion locked against contraints can produce constructive behavior.
As for the "secret of life" stuff, that sounds a little like what Minsky would call a "suitcase word". There's probably no one secret, just a lot of basic physical concepts subtly interplaying with each other. But I suppose McGuffins make for better copy.
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