Thread

1. __MatrixMan__ · 1790482592 · focus · HN ↗

   I feel like "is biology quantum?" gates are kept in a needlessly stringent way.

   They say that biological systems are too warm for quantum coherence to persist long enough to have meaningful effects. But if you have some molecule whose conformation is in a superposition of states--however briefly--and then the environment causes it to decohere and take on some fully determined non-quantum shape... that actual shape is still one of many possible ones into which it did not decohere. The environment has still hacked probability to trigger decoherence into this shape and not some other one, and evolution leans on this.

   If you took a classical bag and filled it with classical locks and classical keys and just shook it around for a while, none of those keys would end up in the locks. But because of this quantum lubricant, ligands binding receptors do find themselves in the appropriate conformation to facilitate signal transduction, even at low concentrations. It's absolutely astounding that it works at all, and in a fully classical world it wouldn't for the same reason that the keys don't end up in the locks when you shake the bag for a while.

   Biology is plenty quantum, and the people who are here to tell you it isn't are citing the abundance of interactions as evidence that it is not quantum, but it's through those many interactions that its quantum nature expresses itself.

   Maybe it's not spooky-action-at-a-distance style quantum. Maybe it's not indeterminate enough for this theoretical purpose or that one. If you're trying to cram god in there, well it might not be quite spooky enough for that, but so much of what happens in the macroscopic world would not happen if the quantum world were not as strange as it is, and that's doubly true for biology.

   1. dekhn · 1790543249 · focus · HN ↗

      If you filled a classical bag with classical locks and classical keys and shook it for a very long time, you would indeed see a small number of keys in locks. There's a non-zero probability set of steps by which that can happen. Am I missing something obvious here?

      1. vanderZwan · 1790577854 · focus · HN ↗

         At the molecular level biology is chemistry, and I think GP is implying that it's often the kind of chemistry that needs quantum mechanics to be explained properly. Now, I don't know how enzymes work, so I don't know if that's true. But I do know that they can do chemical conversions at room temperature where "naive" human chemistry would require temperatures incompatible with life (or pH levels, or pressure, or…).

         So in biology the bag, lock and keys are shaped in such a way that you only have to shake for a short time to have multiple keys come out in locks, and in a particular order or pattern too. That's what makes the whole thing kinda magical. And I would not be surprised if quantum mechanics were involved in the chemistry in ways that classical mechanics cannot explain adequately.

         EDIT: I started typing this yesterday evening and hadn't hit "send" before going to bed, I hadn't seen the rest of the discussion that had taken place since.

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