Science questions not worth a thread I: I'm a moron!

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Question about the salinity of the ocean: what balances the number of sodium and chloride ions flowing in from rivers and the like, so that the salinity stays roughly constant? Why doesn't the salinity of the ocean just increase without bound? Googling this, a popular answer seems to be that life forms consume those ions and leave the salinity roughly constant, but if that's true, wouldn't the oceans have turned into a giant Dead Sea before life developed?
 
Question about the salinity of the ocean: what balances the number of sodium and chloride ions flowing in from rivers and the like, so that the salinity stays roughly constant? Why doesn't the salinity of the ocean just increase without bound? Googling this, a popular answer seems to be that life forms consume those ions and leave the salinity roughly constant, but if that's true, wouldn't the oceans have turned into a giant Dead Sea before life developed?

The main answer: Different chemicals have different solubility indexes. Once a solution is saturated with chemicals, the excess tends to precipitate out of solution, generally. So that explains that the ocean doesn't become salty out of bounds. The floor becomes salty. And also I believe there's a partial molar effect on the amount of solute that a solution can carry where each prior solute (salt) affects how much more can enter the solution.

Also, I'd assume some salt is taken up by organisms. And some salinity goes back to land through the water cycle (e.g. rains, salt nucleates rain drops).

And I'd think coastal swamps play some role in salt content of the oceans.

Also I think you're confused about "salinity". You're talking about ionic balance between positive and negative ions. Salinity is just a generic measure of the total amount of salt ions as typically measured by the conductivity caused by the electrical field of the ions.
 
I've been wondering something loosely along these lines...

From what I understand, life on earth is pretty much entirely dependent on acids: DNA, RNA, the usual vitamins, etc. I don't know if proteins are considered acids.

Why aren't bases the foundation of terrestrial biochemistry? Could it have gone the other way in a different roll of the evolutionary dice? I mean, is this the same thing as the chirality of proteins, or is there something fundamental about acidity viz-a-viz biology that I don't know?
 
Remember that every acid has a conjugate base.

And the base forms are just as important as the acid forms.

Hell, amino acids are acids AND bases, depending on which end of the amino acid you're talking about.
 
Seems like a sophistic question really.

But yeah chirality would be influenced if you had say the choice of acids (protons) or bases (hydroxyls) to put on. E.g. if a molecule was so acidified or basic then it couldn't be chiral (too much protons or too much hydroxyls, then no potential for chirality). But then is chirality really that important other than life favors one form of chirality (left-handed)? Chirality probably helps limit the geometry of molecules letting you encode more info in their arrangement (if you think of inter-molecular associates as having information).

AFAIK, the fundamental chemistry of terrestrial biology is actually dependent upon the properties of water. Acids/bases in life molecules is just nomenclature, since most life is at about a neutral pH.
 
The main answer: Different chemicals have different solubility indexes. Once a solution is saturated with chemicals, the excess tends to precipitate out of solution, generally. So that explains that the ocean doesn't become salty out of bounds. The floor becomes salty. And also I believe there's a partial molar effect on the amount of solute that a solution can carry where each prior solute (salt) affects how much more can enter the solution.

Also, I'd assume some salt is taken up by organisms. And some salinity goes back to land through the water cycle (e.g. rains, salt nucleates rain drops).

And I'd think coastal swamps play some role in salt content of the oceans.

Also I think you're confused about "salinity". You're talking about ionic balance between positive and negative ions. Salinity is just a generic measure of the total amount of salt ions as typically measured by the conductivity caused by the electrical field of the ions.
But the ocean isn't anywhere near saturated, is it? IIRC, it's only about 3-3.5% salt by mass, a factor of about 10 less than the Dead Sea, which is saturated with salt.

You're right that I meant to ask about what removed the ions from the water to keep the number of ions (the salinity) relatively constant, not ionic balance between positive and negative ions. It's still not really clear to me how this works - somehow the ocean has about 10 times less salt than it could have before it would be saturated, and given that rain is fresh water (maybe it contains some salt, but very little compared to the ocean), I don't see how rain over land would reduce the ocean's salinity by any appreciable amount.

I imagine that life would be a major user of sodium and chloride ions. But is it the only thing that has a significant role to play in keeping the ocean's salinity below saturation? And if so, would the oceans have contained Dead Sea levels of salt before life evolved? Seems like it would be hard for life to develop under such conditions, although I know there are extremophiles that can live in the Dead Sea, so maybe that's the answer?
 
I imagine that life would be a major user of sodium and chloride ions. But is it the only thing that has a significant role to play in keeping the ocean's salinity below saturation? And if so, would the oceans have contained Dead Sea levels of salt before life evolved? Seems like it would be hard for life to develop under such conditions, although I know there are extremophiles that can live in the Dead Sea, so maybe that's the answer?

On this point, at the microbial level, life is incredibly diverse as to what it can metabolize and what environmental conditions it can tolerate. In the case of high salt, the exact general term is "halophiles" for "salt-loving".
 
I've been wondering something loosely along these lines...

From what I understand, life on earth is pretty much entirely dependent on acids: DNA, RNA, the usual vitamins, etc. I don't know if proteins are considered acids.

Why aren't bases the foundation of terrestrial biochemistry? Could it have gone the other way in a different roll of the evolutionary dice? I mean, is this the same thing as the chirality of proteins, or is there something fundamental about acidity viz-a-viz biology that I don't know?

Seems like a sophistic question really.

But yeah chirality would be influenced if you had say the choice of acids (protons) or bases (hydroxyls) to put on. E.g. if a molecule was so acidified or basic then it couldn't be chiral (too much protons or too much hydroxyls, then no potential for chirality). But then is chirality really that important other than life favors one form of chirality (left-handed)? Chirality probably helps limit the geometry of molecules letting you encode more info in their arrangement (if you think of inter-molecular associates as having information).

AFAIK, the fundamental chemistry of terrestrial biology is actually dependent upon the properties of water. Acids/bases in life molecules is just nomenclature, since most life is at about a neutral pH.

The chirality of amino acids is unrelated to acidity or basicity since it derives from stereogenic carbon atoms. Simply put, amino acids with the wrong configuration won't be incorporated in proteins.

Under extreme conditions of acid or base, amino acids can lose their stereochemistry, but under such conditions amino acids will be the least of your concerns.
 
From what I understand, life on earth is pretty much entirely dependent on acids: DNA, RNA, the usual vitamins, etc. I don't know if proteins are considered acids.

Well...DNA and RNA consist of bases, so i guess this part of your question eliminates itself :D.
 
Well...DNA and RNA consist of bases, so i guess this part of your question eliminates itself :D.

They're nucleic acids. That's what the A in DNA and RNA stands for. :)

Actually to settle it, you can look at the pKas of polymer. Which is hard, because thymine has a very basic pKa of about 9, and many of the other bases have very acidic pKas of about 2-4. Then add in the effect of the phosphate backbone of the polymer which raises the pKa above biological pH making them acidic which is good so they can base pair by hydrogen bonding. So they are bases at biological pH, else we wouldn't have the double helix. :)

http://forums.civfanatics.com/newreply.php?do=newreply&p=9848608
 
The chirality of amino acids is unrelated to acidity or basicity since it derives from stereogenic carbon atoms. Simply put, amino acids with the wrong configuration won't be incorporated in proteins.

Under extreme conditions of acid or base, amino acids can lose their stereochemistry, but under such conditions amino acids will be the least of your concerns.

What I was saying was you can't have stereo-chemistry if all your substituents are hydroxyls are protons, since that eliminates the possibility of chiral centers. That's what I meant that you couldn't have extremes of acidity or basicity, since then there wouldn't be chiral centers.
 
Is there any rationale whatsoever to the fact that if an electric current is passed along the x-axis, the magnetic field will be in the y-axis?
 
What I was saying was you can't have stereo-chemistry if all your substituents are hydroxyls are protons, since that eliminates the possibility of chiral centers. That's what I meant that you couldn't have extremes of acidity or basicity, since then there wouldn't be chiral centers.

At the same time, if "all your substituents are hydroxyls or protons" then you're not dealing with the amino acids or sugars that are involved in protein or nucleic acid synthesis. The stereochemistry of the smaller building blocks is important because this is what defines the supramolecular structure of biomacromolecules.

I think the extremes of acidity or basicity that I was talking about are somewhat more extreme than what you're talking about; I mean the racemision of stereogenic centres through carbocation or carbanion pathways; the forcing conditions you need for this will kill most organisms.
 
They're nucleic acids. That's what the A in DNA and RNA stands for. :)

Sure, but nucleic acids consist of nucleotides, which are one of the 4 bases AGCT(U) + sugar + phosphate group ;).
:think: never thought about it, but i have no idea where the A in DN/RN chemically comes from. From the phosphate?
 
Is there any rationale whatsoever to the fact that if an electric current is passed along the x-axis, the magnetic field will be in the y-axis?

The magnetic field will form concentric circles in the y-z-plane, instead of just being in the y-axis, but yes, there is a rationale for this given by Special Relativity:

If you have a charge moving with constant speed, Special Relativity postulates, that you can view the process in the inertial system, where this charge is stationary. In this inertial system, the charge does not generate a magnetic field, so a test charge will only see a force caused by the electric field of the charge.

If you take that force and make the necessary transformations from SR to it, to get back to the lab inertial system, this force is exactly the same as the force you would get if you had just calculated the force from the magnetic field.

So a magnetic field is just a relativistic electric field, and thus the direction of the magnetic field is given by SR.
 
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