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Kidney injury can result from repeated rounds of heat stroke and dehydration. The dialysis and death rates among sugar cane plantation workers and migrant crop pickers increase in hotter years if they work in inhumane conditions lackng sufficient rest and hydration breaks. They’re as adapted as can be and still have problems from repeated exposure to extreme heat conditions.

>If I throw a ball in space, I know my hand exerts force on the ball for it to accelerate, but when I let go, it will keep moving forever in a straight path, with no force acting on it. How is that?

Why did the ball start moving?

You exerted force on it.

What would cause the ball stop moving, or otherwise change it's motion?

An external force acting on it, like someone catching it.

Why does the ball move in a straight line with constant speed?

>No force acting on it.

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Its the Cubic Ternary Complex model, you should be able to find some papers on GPCR activation for it that have SBML files you can download and play with

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There's a book called Life on the Edge, by Johnjoe McFadden, that's about quantum biology. In one part he talks about evidence that the sodium pumps in neurons are so incredibly efficient because they somehow induce the sodium atoms to travel as waves rather than particles through their structure. It's incredible stuff.

The intermediate states are irrelevant. It is only the free-energy difference of the two states (bound and unbound) that matter.

Molecular dynamics is adequate in most simple cases. You could say we are limited with what kind of computing power we can apply in complex systems.

You need to think in terms of statistical mechanics. These systems happen in an ensemble. The system has many allowed states, some bound, some not bound. The occupancy of these states depend on the free energy difference of the two states. So we are really talking about probability. In many cases, it is the solubility of the ligand that matters most (how much the ligand prefers to be surrounded by water).

Not entirely accurate. Much of the free-energy of binding is related to entropy, depending on the ligand. A tight binding configuration, even with favorable energy, will not provide strong binding if it is not accessible (high enough favorable entropy).

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Thanks for the answer

>But the scale is far too small for those sorts of concepts of rigidity or even solidity, right?

No, atoms are solid, and the bonds in the molecules are usually quite strong. The lock-and-key analogy is not very good, however. For one thing, molecules and proteins are not rigid. And the binding is a statistical process. It's just that the protein and molecule prefer (by favorable energy and entropy) to be together then apart in solution.

One simplistic way to think about it would be that while random chance has a lot to do with whether a molecule gets to the vicinty of a receptor, once it’s vaguely in the neighbourhood it isn’t all just random luck getting into perfect binding position: chemistry is ultimately electromagnetic, and opposite charges attract by a real force, so the more positive parts that want to bind to negative parts etc., so the right parts of the receptor and molecule will be attracted accordingly until they bind.

Everything in physics is trying to find a local optimum, and there are real forces guiding them to that optimum.

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Molecules have slight positive and negatively charged areas on them. Single bonds can rotate more or less freely assuming the parts they are attached to aren’t too big and hit each other. So it’s almost like they are slightly flexible magnetic rotatable chunky things, and the way they fit into a receptor, (also a chunky magnetic flexible thjng) is by their positive and negative areas matching up with negative and positive areas of the receptor.

It sounds like it would take forever, like it must take so much vibrating around for the exact molecule among millions to slot into place, but molecule speeds are insane, they move FAST. There are enzymes that can grab a molecule, break it apart, let the pieces go, and repeat with s new one…60,000 times in a second.

Lol I tried to make a quick answer ha

I realize I didn't clarify well. I meant just a visual example of a city being ripped from a planet. Earth was largely unaffected.

Your instinct is correct that the physical metaphor is wrong. Proteins are not as solid as a lock and key. Also, a lock and key relies on physical shape. Protein protein interactions rely on shape +intermolecular forces.

https://www.khanacademy.org/science/biology/chemistry--of-life/chemical-bonds-and-reactions/v/intermolecular-forces-and-molecular-bonds