It e.g. wouldn’t use potassium to send signals, I’d imagine. If a design like this exists, I’d expect it to involve totally different parts and steps that do not conflict like this. Something like a novel (to us) kind of ion channel, maybe, or something even stranger.
Does it seem to you that the constraints put on cell design are such that the ways of sending signals and digesting things we currently know of are the only ones that seem physically possible?
This is not a rhetorical question. My knowledge of cell biology is severely lacking, so I don’t have deep intuitions telling me which things seem uniquely nailed down by the laws of physics. I just had a look at the action potential wikipedia page, and didn’t immediately see why using potassium ions was the only thing evolution could’ve possibly done to make a signalling thing. Or why using hydrochloric acid would be the only way to do digestion.
You’re a chemical engineer. Your task is to manufacture chemicals A and B. But you only get one well-mixed tank: all the precursors of chemical A have to mix with each other and with the precursors of chemical B without undesired cross-reactions, and the A and B production process need to take place in the same salinity environment and the same pH environment, etc.
Maybe that’s doable.
Oh hey, now also please manufacture chemicals C,D,E,F,G,H,I,J and K. You still have one well-mixed tank in which to do all those things simultaneously.
Maybe that’s doable too. Or maybe not. And if it is doable at all, presumably the efficiency would be terrible.
At some point, you’re going to throw up your hands and go to your boss and say “This is insane, we need more than one well-mixed tank to get all this stuff done. At least let me have a high-pH tank for manufacturing A,B,E,G,H and a low-pH tank for manufacturing C,D,F,I,J,K. Pretty please, boss?”
Anyway, you can say “Design space is huge, I bet there’s a way to manufacture all these chemicals in the same well-mixed tank.” Maybe that’s true, I don’t know. But my response is: there is a best possible way to manufacture A, and there is a best possible way to manufacture B, etc., and these do not involve the exact same salinity, pH, etc. Therefore, when we put everything into one tank, that’s only possible by making tradeoffs. A chemical plant that has multiple tanks will be way better.
Back to biology. (I’m not an expert on cell biology either, be warned.)
A cell cytoplasm is a well-mixed chemical reactor tank, as far as I understand. It’s not compartmentalized (with certain exceptions).
My strong impression is that there are no one-size-fits-all jack-of-all-trades cells. Not in multicellular life, and not in single-cell life either. Different single-cell species specialize in performing different chemical reactions.
Thus, we can have single-cell organism Q that eats food X and spits out waste product Y, and then a different single-cell organism P eats Y and spits out waste product Z, etc. We can kibbitz from the sideline that Q is being “wasteful”: why spit out Y as waste, when in fact Y was digestible in principle—after all, P just digested it! But from my perspective this is pretty much expected. Maybe digesting Y and digesting X require very different salinity or pH, for example. So in order to digest Y at all, the cell Q would need to be much worse at digesting X, and that tradeoff winds up being not worthwhile.
didn’t immediately see why using potassium ions was the only thing evolution could’ve possibly done to make a signalling thing. Or why using hydrochloric acid would be the only way to do digestion.
It could be chloride ions instead of potassium, as far as I know. But there are only so many elements on the periodic table, and many fewer that are abundant in the evironment, and they all have different properties which may be disadvantageous for a particular function. There are other ways to do digestion, but they don’t all spend identical resources and produce identical results, right? So there are tradeoffs.
It e.g. wouldn’t use potassium to send signals, I’d imagine. If a design like this exists, I’d expect it to involve totally different parts and steps that do not conflict like this. Something like a novel (to us) kind of ion channel, maybe, or something even stranger.
Does it seem to you that the constraints put on cell design are such that the ways of sending signals and digesting things we currently know of are the only ones that seem physically possible?
This is not a rhetorical question. My knowledge of cell biology is severely lacking, so I don’t have deep intuitions telling me which things seem uniquely nailed down by the laws of physics. I just had a look at the action potential wikipedia page, and didn’t immediately see why using potassium ions was the only thing evolution could’ve possibly done to make a signalling thing. Or why using hydrochloric acid would be the only way to do digestion.
You’re a chemical engineer. Your task is to manufacture chemicals A and B. But you only get one well-mixed tank: all the precursors of chemical A have to mix with each other and with the precursors of chemical B without undesired cross-reactions, and the A and B production process need to take place in the same salinity environment and the same pH environment, etc.
Maybe that’s doable.
Oh hey, now also please manufacture chemicals C,D,E,F,G,H,I,J and K. You still have one well-mixed tank in which to do all those things simultaneously.
Maybe that’s doable too. Or maybe not. And if it is doable at all, presumably the efficiency would be terrible.
At some point, you’re going to throw up your hands and go to your boss and say “This is insane, we need more than one well-mixed tank to get all this stuff done. At least let me have a high-pH tank for manufacturing A,B,E,G,H and a low-pH tank for manufacturing C,D,F,I,J,K. Pretty please, boss?”
Anyway, you can say “Design space is huge, I bet there’s a way to manufacture all these chemicals in the same well-mixed tank.” Maybe that’s true, I don’t know. But my response is: there is a best possible way to manufacture A, and there is a best possible way to manufacture B, etc., and these do not involve the exact same salinity, pH, etc. Therefore, when we put everything into one tank, that’s only possible by making tradeoffs. A chemical plant that has multiple tanks will be way better.
Back to biology. (I’m not an expert on cell biology either, be warned.)
A cell cytoplasm is a well-mixed chemical reactor tank, as far as I understand. It’s not compartmentalized (with certain exceptions).
My strong impression is that there are no one-size-fits-all jack-of-all-trades cells. Not in multicellular life, and not in single-cell life either. Different single-cell species specialize in performing different chemical reactions.
Thus, we can have single-cell organism Q that eats food X and spits out waste product Y, and then a different single-cell organism P eats Y and spits out waste product Z, etc. We can kibbitz from the sideline that Q is being “wasteful”: why spit out Y as waste, when in fact Y was digestible in principle—after all, P just digested it! But from my perspective this is pretty much expected. Maybe digesting Y and digesting X require very different salinity or pH, for example. So in order to digest Y at all, the cell Q would need to be much worse at digesting X, and that tradeoff winds up being not worthwhile.
It could be chloride ions instead of potassium, as far as I know. But there are only so many elements on the periodic table, and many fewer that are abundant in the evironment, and they all have different properties which may be disadvantageous for a particular function. There are other ways to do digestion, but they don’t all spend identical resources and produce identical results, right? So there are tradeoffs.