Photosynthesis May Rely On Quantum Effect 234
forgethistory sends us to PhysOrg for a summary of new research suggesting that the near instantaneous energy transfer achieved by photosynthesis may rely on quantum effects. From the article: "Through photosynthesis, green plants and cyanobacteria are able to transfer sunlight energy to molecular reaction centers for conversion into chemical energy with nearly 100-percent efficiency. Speed is the key — the transfer of the solar energy takes place almost instantaneously so little energy is wasted as heat. How photosynthesis achieves this near instantaneous energy transfer is a long-standing mystery that may have finally been solved."
The Plants Are Right to Laugh at You, Ralph (Score:5, Funny)
Re:The Plants Are Right to Laugh at You, Ralph (Score:5, Funny)
Maybe so, but then some herbivore eat a thousand of them, we eat a hundred herbivores, and we're the benefactor of all their magic!
If humans were photoheterotrophic or photoautotrophic, we wouldn't have enough energy to do much more than sit there sulking like a stupid fern. One of the sad realities of a creature like Swamp Thing [imdb.com] (an apparent photoautotroph) is that he wouldn't really be able to move quickly at all. It'd be very easy for some cow to walk up and start nibbling on him (oh sweet irony). Adrienne Barbeau would have to dump his ass for something higher on the food chain like an amoeba.
Adrienne Barbeau was hot in Swamp Thing. You really want to give that up just so you can have quantum-enhanced solar power? Wait, that does sound pretty cool.
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The Swamp Thing was a plant elemental, it probably drew energy direct from the Green rather than relying on its own surface photosynthesis. That would allow it to tap energy from the whole plant life of the earth; easily enough for its purposes. Still, there is something faintly ridiculous about a hero powered by sunlight; such an idea would never fly.
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Now that's impressive. I set up a feed-line about how a hero powered by the sun would never fly, I'm expecting to hear about Kal-El and Kryptonian physiology and Earth's yellow sun and so forth. My congratulations, then, for finding the truly geeky option :-)
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Maybe so, but then some herbivore eat a thousand of them, we eat a hundred herbivores, and we're the benefactor of all their magic!
If humans were photoheterotrophic or photoautotrophic, we wouldn't have enough energy to do much more than sit there sulking like a stupid fern.
Hey, be nice to our existing photosynthesis plant underlords! They are the ultimate green pacifist liberals. Would you allow ot
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Especially these guys [wikipedia.org].
PS: It's odd that until now I never noticed what a potato plant looks like, even after all these years of consuming their delicious tubers.
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not solved, just possibly more understood. (Score:2, Insightful)
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Re:not solved, just possibly more understood. (Score:4, Interesting)
All interactions at the atomic level are quantum effects. A photon can only interact through quantum effects. The statement in the article is totally meaningless.
We have known that photosynthesis is a quantum effect since Einstein's paper on black body radiation.
More to it than that (Score:5, Informative)
TFA suggests that the hopping uses quantum superposition to traverse the chlorophyll molecules more quickly. When the traversal reaches the pheophytin, the superposition collapses into that single state which found the pheophytin.
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Re:not solved, just possibly more understood. (Score:4, Interesting)
Re:not solved, just possibly more understood. (Score:4, Interesting)
1) If and only if the photon is of the proper energy. In general, during solar energy conversion of all kinds, you require a certain amount of energy to kick an electron out of the pigment. Less than that energy, and nothing happens. More than that energy, and the excess is wasted.
2) This only applies to the original photon capture. The total process of turning solar energy to sugars in plants is about 35%. Due to losses for biochemistry, the overall system is very inefficient -- usually just 1-2% in most crop plants, and a fraction of a percent in non-crop plants. Sugarcane is exceptionally high at 8%, still well below most silicon cells.
Now, dye-based cells *are* in development. The key for them is not that they're very efficient (they tend to be very inefficient), but that they should be very cheap to produce (no silicon refining needed). Of course, a few companies (such as Nanosolar [nanosolar.com]) are working on commercializing high-efficiency dye-based cells. I read nanosolar's main patent at one point; basically, the efficiency problem with most organic solar cells is an uneven distribution of electron donors and receivers that leads to most of the electrons being wasted. In Nanosolar's case, they build a crystalline scaffolding that the dye gets embedded into at regular intervals, then dissolve the scaffolding.
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I'm sure a lot more things rely on quantum effects (Score:2, Insightful)
Re:I'm sure a lot more things rely on quantum effe (Score:5, Insightful)
Re:I'm sure a lot more things rely on quantum effe (Score:5, Funny)
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Nothing mystical about it. While I do believe that stuff on a quantum
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Re:I'm sure a lot more things rely on quantum effe (Score:4, Funny)
Just kidding. I will leave now.
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Comment removed (Score:5, Interesting)
Re:I'm sure a lot more things rely on quantum effe (Score:5, Interesting)
Would that mean that attempts to upload human minds to computers would fall foul of the no-cloning theorem? Such constraints on the duplication of quantum information would have interesting effects on philosophical problems of identity.
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Red Mars was good, but by Blue Mars, I gave up partway through thinking I really don't care about these people or their dumb politics.
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That's about the way I felt about Red Mars, and I wasn't even reading it but listening to the book on tape while commuting. Actually more the soap operas than the politics. Maybe if I'd been reading it I could have just skipped those bits.
(That's what I did with the Chronicles of Covenant that somebody once gave me. Read the beginning and ending bits where he's in the real world, and skipped over the stupid s
Even if... (Score:2)
It would prevent backups or duplicates, though.
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so when I did an MRI (Score:2)
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Re:I'm sure a lot more things rely on quantum effe (Score:5, Funny)
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Maybe his spell checker uses quantum effects!
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Hey! Mine keeps doing that, too!
Philosophical implications? (Score:4, Insightful)
Re:I'm sure a lot more things rely on quantum effe (Score:3, Interesting)
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"God, we are fining you 3 million Euros a day until you provide fully documented APIs for all neural functions"
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Re:I'm sure a lot more things rely on quantum effe (Score:4, Interesting)
Other people have proposed this before, but present a theory of why quantum effects may be necessary. Roger Penrose makes the argument that we can compute things that a Turing-style computer could not compute, so something else must be going on. His proof that some things we do cannot be done by a Turing style computer isn't exactly accepted though, and no-one seriously believes that the brain works in this way in any case.
Also, consciousness is not the same thing as "self-awareness". Is a dog conscious? Is it self-aware? What about a rabbit? When I dream, I'm not usually self-aware, but there's some sort of consciousness there. What about phenomena like blind-sight, where a person is self-aware, but unconscious of visual information, even though they can access that information by guessing remarkably accurately, just without any direct consciousness of it. Does this mean that these supposed quantum-consciousness effects have broken down only for information originating in visual centers, but keeps working on all other information?
Of course, coming from quantum theory, there is the Copenhagen Interpretation which places a special status on the 'observer' - but no-one has managed to define what an observer is, or whether they must be conscious or not.
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What things can we compute that a Turing machine cannot?
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It has something to do with Godel's proofs - something along the lines that you can't prove something to be true or false inside a particular system, but since we as humans can see that something is true/false nevertheless, so we must be doing something different.
I don't think the argument holds up very well myself (we can apply lots of different systems, for one thing, we aren't limited to only one), and I am sure I am som
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I always find it interesting (not directed at you) that people assume it's some crazy wacko replacement for religion, etc... when someone suggests that our minds might actually be linked to something outside ourselves. Is this really so hard to believe? That in our becoming conscious perhaps something happens, behind the scenes, say some sort of entanglement across some tightly coiled dimen
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Re:I'm sure a lot more things rely on quantum effe (Score:2)
Penrose suggested as much, in his book The Emperor's New Mind [wikipedia.org]. However, this theory is not regarded as serious by any neuroscientists that I am aware of; chemistry and electricity/magnetism is supposed to be able to account for brain function, according to them.
Actually, the real philosophical implications come f
Quantum mind (Score:2)
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It's called the Orch-OR theory [wikipedia.org] and is a popular object of ridicule amongst neuroscientists. While consciousness is a very active field of research and there is still much to be d
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Re:I'm sure a lot more things rely on quantum effe (Score:2)
Consciousness can be easily explained in three words: It's an illusion. Well, okay, one of those three words is a contraction.
Re:I'm sure a lot more things rely on quantum effe (Score:2)
Like, say, "Color" (or more accurately, radiative/absorbtive wavelength) in general, a completely quantum phenomenon.
TFA does a poor job of mentioning this, but the fact that plants use quantum effects doesn't exactly count as a "new" discovery. Only the level of detail of our understanding of the transfer lacks completeness.
To put the "newness" of this discovery another way (FTA):
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Where did you get the idea that there are "no philosophical implications"?
Okay, let me rephrase that... "No philosophical implications without invoking some flakey new-agey pseudoscientific BS". I actually had (something like) that as as my original phrasing, but decided to give you the benefit of the doubt that you didn't mean anything so fluffy. My apologies for overestimating your intended meaning.
The mind-body problem is a h
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The Answer is No. although the braind and it's compnents are all physical objects in this universe, that are the
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On the one hand you are right, on the other you are wrong.
There have been many books that proposed the idea you are dwelling on. http://www.google.com/search?hl=en&q=Penrose+quant um+mind&btnG=Google+Search [google.com]
One of them "The Emperor's New Mind", by Roger Penrose, looks into this closely and comes to the same conclusion. However I would be quite surprised if conciousness "actually" boils down to a single physic
Re:I'm sure a lot more things rely on quantum effe (Score:2)
Even more amazing... (Score:5, Insightful)
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Yeah. I mean, who would have guessed that a chemical process in which energy from light causes atoms to bind in different ways could have anything to do with quantum mechanics? Crazy!
Re:Even more amazing... (Score:4, Funny)
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I don't know what the "nope" is supposed to disagree with. The statement that QM and GR don't get together? You appear to agree with that. The statement that you'd get a Nobel prize for combining QM and (general) relativistic effects? You would, if you could provide strong support for such a theory.
As for your own statement, quantum theory works fine in curved spacetime, as long as you ignore the backreaction of the quantum fields on spacetime geometry. If you don
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By 'nope' I mean that QM and GR _do_ work together, because we've tested both of them and found them to be correct. We just don't know how to use both of them at the same time
And quantum mechanics and special relativity (i.e. quantum mechanics in flat Minkowski space) were successfully united back in 30-s. It's GR which causes problems.
String theory has exactly the same problems with renormalization.
Re:Even more amazing... (Score:5, Interesting)
Nuclear Sense of Smell vindicated? (Score:4, Interesting)
He's apparently gone on to success in the perfume industry.
Someone find the link... this is driving me nuts.
Re:Nuclear Sense of Smell vindicated? (Score:4, Informative)
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Wasn't that because bitter almonds actually do contain cyanide ?
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The resonance theory is a good and interesting alternative, despite serious difficulties understanding the mechanism.
Re:Nuclear Sense of Smell vindicated? (Score:5, Informative)
http://science.slashdot.org/article.pl?sid=06/12/
Unfortunately, the original Nature article is now subscriber only (http://www.nature.com/news/2006/061204/full/0612
I don't understand (Score:2)
Is that even close to whats being described here ?
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Oh boy. (Score:4, Funny)
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Speed helps, but that's only half the picture (Score:5, Informative)
I can name plenty of chemical reactions that are complete on the femtosecond scale, and while speed helps, that's certainly not the whole picture. What matters is how mismatched the energy levels between the reactant and the product are. When transitioning between energy levels, either energy is transferred out of the system by nonradiative release (heat), luminescence, photofragmentation, or transfer to a chemical partner - this last case is what the article is referring to. Getting to an energy level which can react is going to result in a heat deposition for at least some photons because any photon of a higher energy than the reacting state must deposit some of that energy just to be able to react at all.
http://www.monos.leidenuniv.nl/smo/basics/images/
The squiggly lines show possible heat depositions - the molecule starts in the ground state, absorbs a photon (the yellow up arrow), then relaxes to the excited state. This excited state then does whatever it's going to do. If 100% of the time under a set of conditions (i.e. a quantum yield of 1.00), the excited molecule follows a particular pathway we call that perfectly efficient. In the specific example of photosynthesis, this means that all of the absorbing chlorophylls transfer the energy along the photosynthetic pathway (I'm lumping all the subsequent processes together here). It does not mean that 100% of the energy got transferred along the way - there will always be some photon that deposits more energy than the reacting state has, meaning some energy will be converted to heat.
In short form (if you didn't feel like reading all this): efficiency in this case refers primarily to how often the molecule dumps its energy into photosynthesis instead of all to heat, luminescence, etc. It's not referring to the energy throughput, as some photons will always be an imperfect energy match, and the extra energy will end up as heat.
Photovoltaics? (Score:2)
100% efficiency (Score:5, Informative)
Yeah, sure the energy transfer efficiency is 100% for every photon that participates in the reaction. But of all the photons falling on the leaf, hardly 2% of them participate in reactions. Some gets reflected, some gets absorbed without any reaction. Even solar cells have better energy conversion efficiency than plants. Really. As for quantum effects, almost all the photo reactions are quantum mechanics. They have to be. The film camera emulsion has greater percentage of photons participating in reaction than chlorophyll.
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Moreover, a plant-derived solar cell might be cheaper and easier to produce, essentially growing itself rather than requiring high-grade silicon, etc.
Re:100% efficiency (Score:5, Interesting)
But one thing we should also realize is that, nature has not produced a more efficient photosyntesis process. Plants do not use their energy for mobility. Just to grow. Growth is limited by other resources like minerals and water. So there might not be additional survival value in developing a more efficient photosynthesis process. But still we should be open to the possibility that 2% efficiency is probably the maximum for photosynthesis, using water+co2, producing C12H22O11 (sugar) and oxygen.
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My dream is just humongous mechanized cow stomachs. Large digesters that take in basic plant bio mass, weeds, corn stalks and other basic plant material on one end, chop them up and grind them using steel blades, passing them on to chambers filled
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100% (Score:3, Informative)
Likely more biological examples too (Score:2)
Considering the amount of time
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Metachlorians (Score:2)
Here it comes.... (Score:2)
quantum plant monster ... (Score:2)
Sound like the plot of a movie.
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Unfortunately, yes. The fact is there are a lot of delusional people 'speaking in tongues' every Sunday at their local congregation, readily absorbing whatever anti-intellectual claptrap is thrown their way. Ridicule provides mutual assurance among the rest of us that this thinking is aberrant. That keeps mainstream politicians from pandering to it in overt ways. Organized religion no longer has any effective means
On Ridicule. . . (Score:3, Insightful)
Hm. An interesting argument.
While in this particular case, the religious poster is being silly, I'm not sure I agree with your analysis of ridicule.
I suppose that ridicule being, "Well aimed", as you suggest, is the key.
Unfortunately, virtually every group I've ever seen uses ridicule to discredit whatever opposing viewpoint they find threatening. Not all of them are right,
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