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I think the necessary background fact here is that chlorophyll is a miracle chemical because it's safe. Not 'cause it's efficient. It's not efficient at splitti
by Nomentatus 4y ago
I think the necessary background fact here is that chlorophyll is a miracle chemical because it's safe. Not 'cause it's efficient. It's not efficient at splitting water, about 1%, but unlike so many other chemicals that can split water when hit with photons, it can perform the job while producing very few harmful free radicals. That's chlorophyll's secret sauce. Since green is a relatively high frequency that's intense in sunlight, it's safer to filter that color out. "Noise" here means a less smooth chemical process will produce more free radicals.
- blowski 4y agoFor the novices like me, whats the benefit in producing fewer free radicals?
- pid_0 4y agoFree radicals will cause cell damage and thus death or cancer
- smiley1437 4y agoFree radicals are extremely reactive and can form bonds in undesirable ways in cellular chemistry, which is generally bad for the organism, potentially causing all sorts of cell damage. Cells produce anti-oxidant defenses to regulate free radicals such as the delightfully named "Superoxide Dismutase" enzyme: https://en.wikipedia.org/wiki/Superoxide_dismutase https://en.wikipedia.org/wiki/Superoxide_dismutase
- anonymous_sorry 4y agoAs an aside, there is poor evidence that consumption or topical application of anything artificially high in anti-oxidants does any good for healthy people, although you see "antioxidants" used to sell crap all the time. Maintaining the right balance between free radicals and anti-oxidants is the sort of thing biology is pretty good at on its own. Trying to put a finger on the scales in one direction or another is probably pointless at best.
- Ekaros 4y agoWhen thinking about it it seems pretty weird. Wouldn't most free radicals either enter via lungs or digestive tracts? And those will have plenty of stuff to react before any anti-oxidant can get to work... And anti-oxidants spreading through body on other hand seems bit worrying.
- tpm 4y agoMost free radicals are products of reactions inside the body and the body does have mechanisms to deal with them, even if not 100% sometimes.
- Nomentatus 4y agoFree radicals - in this case often oxyen or hydrogen on its own - are highly reactive as others have said. What that means is that they'll grab atoms from anything ripping pretty much any other molecules in the area apart, and releasing a punch of energy when they do that, which could do further damage.
- teaearlgraycold 4y agoMy understanding is free radicals are literally atom sized bombs. Bombs are trouble because they lead to dangerously quick oxidation, transforming a solid into a gas in milliseconds. Now consider you are a cell. A lot of things you consider important are individual molecules. Free radicals are oxygen ions. So get a few of those ions inside of you and your important molecules are getting oxidized. They’re getting ripped apart. The same as a grenade in a trench. But at the indivisible scale.
- caper 4y agoInteresting - why would fluctuation of the energy flow into the biochemical cascade cause an increase in free radical production? If this is the case then seems a lot more likely and evolutionarily sound than the efficiency interpretation; unless there is some second order effect of the rate of photosynthesis on its efficiency/completion that couple with some sort of initial energy barrier I struggle to see how smoothing fluctuations by using non-proximal wavelenghts would be more efficient than allowing fluctuations with greater absorption across the spectrum (and so greater net energy absorption). Some more basic survival mechanism like the free radical one you propose just seems to be more intuitive. With green colouration a circumstantial bedfellow of the other chemical properties rather than the master. Still speculative of course. Keen to hear your thoughts.
- currenciessfe 4y agoEneregy is conserved. If it "misses" the reaction center, it will hit something else like a stray bullet. > Non-photochemical quenching (NPQ) is a mechanism employed by plants and algae to protect themselves from the adverse effects of high light intensity. It involves the quenching of singlet excited state chlorophylls (Chl) via enhanced internal conversion to the ground state (non-radiative decay), thus harmlessly dissipating excess excitation energy as heat through molecular vibrations. NPQ occurs in almost all photosynthetic eukaryotes (algae and plants), and helps to regulate and protect photosynthesis in environments where light energy absorption exceeds the capacity for light utilization in photosynthesis.[1] https://en.m.wikipedia.org/wiki/Non-photochemical_quenching https://en.m.wikipedia.org/wiki/Non-photochemical_quenching
- Nomentatus 4y agocurrenciessfe 's answer above is better than this crude comment, but: just the extra heat randomizing reactions would be a problem.
- hun3 4y ago> Since green is a relatively high frequency that's intense in sunlight, it's safer to filter that color out. What about (ultra-)violet light?
- throwaway0asd 4y agoMore specifically green is far higher in luminosity, which is about radiation power and not frequency. https://en.m.wikipedia.org/wiki/Luminosity https://en.m.wikipedia.org/wiki/Luminosity
- Nomentatus 4y agoThe energy of (one photon worth) of electromagnetic energy does indeed increase with frequency. So green is more problematic than the same number of red photons. But you're right that if there were few green photons coming in and a ton of red, red might be blocked, and green not.
- sigmoid10 4y agoIt actually isn't. The dominant frequency of solar irradiation is dependent on choice of spectral variables and could just as well be said to be in the infrared, when plotted as a function of frequency. So with the same argument, plants would be better off reflecting that. Especially when you consider that absorption happens as transitions between energy levels (i.e. frequencies) in molecules. However, in truth it simply doesn't make sense to talk about point frequencies in a density distribution. [1] https://www.oceanopticsbook.info/view/light-and-radiometry/level-2/common-misconception https://www.oceanopticsbook.info/view/light-and-radiometry/l...
- Razengan 4y agoHah I love these cycles of [dis]information and correction on Reddit/HN: > Commenter A: [cool fact] > Reader: Oh! Interesting! > Commenter B: Actually no > Reader: Oh...
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- throwaway0asd 4y agoThe math to compare colors is more simple than that: https://www.w3.org/TR/WCAG20/#relativeluminancedef https://www.w3.org/TR/WCAG20/#relativeluminancedef Blue is a slightly higher frequency than both red and green but green has a dramatically higher luminosity. Simple arithmetic applied against that less simple luminosity formula allows for contrast comparisons.
- wuschel 4y agoWould you have a reference to comparative studies re the “safety” of chlorophyll in contrast to some other energy transformers, say, mitochondria?