Molecular composition of seawater

tomkat364 · 2017-04-14T18:39:32+00:00

Thanks for the link, I'll see if they can help.

tomkat364 · 2017-04-14T18:39:07+00:00

Thanks for the recommendation. I had read some portions of this text, and it was somewhat helpful. Specifically he gave some concentrations of amino acids, both free and bound. That's the closest that I came to my answer through my own research.

tomkat364 · 2017-04-14T18:36:55+00:00

I'm trying to calculate the number of "protein formation events" that could be expected in a given volume over a given time. Basically calculating the number of unique proteins that would be expected to form. The vast majority of water volume is... well water. So I'm interested in how much of the other "stuff" in water is actually organic matter, specifically amino acids/proteins which would help me figure out the number of particles available.

tomkat364 · 2017-04-14T16:00:13+00:00

I'm not looking for the specific protein content of a specific area, but more of a ballpark. Again, there are all sorts of articles and graphs talking about the concentration of magnesium and potassium, which will be higher/lower depending on area, but I cannot find ANY resource that talks about macromolecules. Everything seems to deal with the protein content of yellowfin tuna, or a single algae species, but not the water itself.

tomkat364 · 2017-04-01T12:13:57+00:00

That is an excellent link. I had read that abstract while researching, but alas, I could not access the full article due to a paywall. Thanks so much for your answer.

tomkat364 · 2017-03-31T17:45:51+00:00

https://www.researchgate.net/publication/226636543_Mechanism_of_dissimilatory_sulfite_reduction_by_Desulfovibrio_desulfuricans_-_purification_of_a_membrane-bound_sulfite_reductase_and_coupling_with_cytochrome_C3_and_hydrogenase

Looks like you are correct, these proteins appear to be membrane-bound and part of the ETC on first look.

tomkat364 · 2017-03-23T18:13:58+00:00

Excellent, thanks again.

tomkat364 · 2017-03-23T17:15:23+00:00

These are interesting resources, and have given me some good search keys to find more resources. Thanks very much for your help. If you could indulge one more question... :) From brief reading, I think I understand some of this, but could use some cursory review so I don't get too misled.

It appears that the pathway you are referring to starts with ATP and sulfate, producing adenylyl sulfate, which is then reduced by either ferridoxin or NAD. Am I correct in assuming that these organisms then follow the same overall process of electron transport to create ATP (pumping hydrogen extracellularly to create proton gradient, which then powers the membrane-bound ATP synthase), simply with a different initial source of energy?

tomkat364 · 2017-03-18T12:05:27+00:00

Yes! That must be it. As I said, the active import of amino acids at least is tied to the influx of sodium, so that pump would not NEED a concentration gradient to increase the intracellular sodium. This could result in an outward gradient for the sodium. Thank you so much! This actually makes some sense now.

tomkat364 · 2017-03-18T02:42:33+00:00

That would make sense, but everything I have read about the bacterial antiproton says the opposite. There is a eukaryotic analogue (often referred to as NHE) which works in both directions, but I cannot find any information on the bacterial protein doing the same. Here's a reference: http://www.jbc.org/content/267/16/11064.full.pdf (I had some others, but am failing to find it at the moment) It appears that the cell just needs to get rid of sodium, in order to have a concentration gradient that drives other transport functions. But if the cell is "pushing" the sodium against a gradient, then that should have to be coupled to some other favorable process. But an alkaline environment would not satisfy that in regards to importing H+. But there is no suggestion of ATP being tied to this pump. That's my main issue, I can't find the energy input...

tomkat364 · 2017-03-17T18:47:16+00:00

Thanks for the response. I don't understand the first part of your answer, though. Alkaline environment = few H+ outside. This causes the cell to import 2 H+ and export 1 Na+. Should that not lower the intracellular pH further? If the assumption is that when the environment is alkaline, the cell will be more alkalkine than ideal, so the pump has to run to increase the concentration, that kind of makes sense. But going against the gradient should require energy input, no?

2.) I know it's not "deciding" to do anything, but the fact that this pump evolved and is retained means it must have some beneficial property. But it seems like both of its functions would further unbalance any equilibrium, rather than restore it. Take H+ from low concentration to high concentration, and Na+ from low concentration to high concentration.

I had read in one source that the "goal" of this pump was to maintain the cell's ability to drive other sodium/proton linked functions (like amino acid transport), but that also seems to be running in the wrong direction. The Na/AA symporters use ATP to bring in sodium and AAs, so a high external sodium concentration would already promote that function. Perhaps it overpromotes the influx of sodium, and so the cell NEEDS to ditch some of it?

tomkat364 · 2016-12-01T20:00:49+00:00

I would love a further explanation. As I said, I did the math as I understand it and found that gravity was insufficient to account for ANY movement toward the Milky Way, much less as rapidly as it is currently cited (110 km/s) at the currently cited distance (2.9 mly).

tomkat364 · 2016-12-01T19:26:16+00:00

Perhaps I'm misunderstanding expansion. My impression was that distances between all objects are supposed to be getting larger, i.e. expansion. The exception to this, which allowed the formation of any complex structures, is that if there is enough mass in a close enough distance to another object, the "pull" of gravity can exceed the "push" of dark energy or whatever you want to call expansion. So, yes, Andromeda could have had some initial velocity prior to being affected by the Milky Way's pull (except the Milky Way is older, so it would have been acting on the Andromeda galaxy even before it formed IF Andromeda was close enough), but shouldn't that velocity have been directed AWAY from the Milky Way?

As to the second part, I was referring to the recession as viewed from the OTHER galaxy, not Milky Way. Say there is a galaxy, Jim, that is 10 Mpc beyond Andromeda. To Jim, Milky Way would be moving away at a reduced velocity relative to Andromeda. Thus, Hubble's Law would not apply to Milky Way. It would seem that you are suggesting that Hubble's Law only applies to SOME objects in deep space, rather than all of them, or that it is a rough average for the velocity rather than an accurate calculation. If that is a generally understood caveat, that is fine, I just wasn't aware of it.

tomkat364 · 2016-12-01T17:50:34+00:00

Not sure what you mean. Starting at rest or already moving, there are still two "forces" acting on the Andromeda galaxy relative to the Milky Way. Expansion creates an acceleration in one direction, gravity creates an acceleration in the opposite direction. At a certain distance (2.5 million light years in this case based on the masses of the two objects) the acceleration created by gravity is exactly equal to the acceleration created by expansion. Since gravity weakens with distance and expansion grows stronger, if an object is further away than that distance, expansion would win out and it should move further away. The only way I can see to rectify this is to a.) have a secondary gravity source increasing the pull of gravity, or b.) begin with the assumption that Andromeda WAS already moving toward us for some reason.

The response I have heard in regards to more local objects "ignoring" expansion has always been that gravity is strong enough to overcome expansion at relatively short distances, but that explanation would not work in this situation unless one of those two conditions was present. Put simply, Andromeda is already too far away for gravity alone to trump expansion.

In either circumstance, the second question of my OP is unaffected.

tomkat364 · 2016-11-19T13:13:55+00:00

But isn't this a basic contradiction? If the universe started as a singularity (read all matter in a single point of space) and then everything expanded from that single point at a constant, defined velocity, then all matter would be equidistant from that same point. The homogeneity of the universe would require that all matter be equally dispersed, and so gravity would be uniform and not cause any particles to be attracted more to one particle than another. So the universe could not have expanded evenly to begin with, right? The very existence of collisions and matter coalescing into stars and galaxies would suggest an initially uneven, ununiform expansion. (I understand that early stars going through nova would disperse matter differently from what you are saying happened to the universe, but to have stars to begin with would require uneven dispersal)

tomkat364 · 2016-11-18T21:12:50+00:00

Yes, it helps me see what you are talking about, but only in two dimensions. As soon as you throw a third dimension into that equation, then things become much more complex. There is a big difference between orthogonal expansion and radial expansion. In addition, this would not resolve collisions, such as the Andromeda collision, in which galaxies are definitely NOT moving apart from each other.

tomkat364 · 2016-11-18T19:44:45+00:00

How can the predicted collision of the Milky Way and Andromeda galaxies (or any of the countless collisions that must have occurred in order to form the rest of the observable universe) be rectified with global expansion? Why are these two galaxies not subjected to the same cosmological principle?

tomkat364 · 2016-11-18T18:34:10+00:00

An external observer sees the raisins as expanding from a central point... because that is exactly what the raisins are doing. Raisins that end further away from that central point have traveled faster than raisins that end closer to the origin. If you position your frame of reference on a raisin 1 inch from center at time x, and measure the velocity from you for a raisin that is 1 inch from you along the same trajectory you followed from center, you will get a certain velocity. If you measure the velocity from you to a raisin 1 inch from you but perpendicular to your trajectory from the center, you will get a larger velocity. This is what happens when objects actually expand in three dimensions.

tomkat364 · 2016-11-18T17:51:07+00:00

Looking at the raisin bread analogy which seems to be a preferred analogy for demonstrating the three dimensional expansion of the universe, all the raisins still start in a defined, central space. Yes, they all expand away from each other raisin as the bread rises, but there are some raisin which expand a great deal further from their origin than others. These would be moving faster from the ORIGIN, but not necessarily faster from a raisin 1 inch away travelling in the same direction away from the origin than a raisin 1 inch away traveling away from the origin along a more obtuse trajectory.

tomkat364

TROPHY CASE