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twall11347243
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At Earth's 1g, is the rate of diffusion equal to the rate of sedimentation for cellular molecules (or proteins)? The diffusion rate is higher, correct?
Thanks.
Thanks.
If there is nothing else influencing the position (and usually there is), and if the object is denser than water, sure.twall11347243 said:They don't say the densities. I'm trying to figure out is what they're trying to tell me is that everything (all atoms, molecules) in the air or water or cytosol of the cell undergoing this 'isothermal settling' or sedimentation equilibrium... where it creates this barometric distribution of more at bottom than top?
Why should it?twall11347243 said:A true solution is homogenous throughout.
I think that assumes the surrounding medium is a gas and doesn't take up volume. The actual effect should be even smaller.twall11347243 said:Lg = KbT/mg
It does (in the absence of active transport, production or destruction mechanisms), but the equilibrium is a nearly homogeneous distribution.twall11347243 said:Something that small's thermal energy (KT) would be >>> much greater than it's gravitational potential energy (mgh) so it should never reach sedimentation equilibrium.
That is an odd definition if potential energy is limited.twall11347243 said:The definition of sedimentation equilibrium is that thermal energy = gravitational PE (and diffusion rate = sedimentation rate).
Everything will give a non-zero gradient if you wait long enough. Even oxygen and nitrogen in the atmosphere would have a tiny gradient if we would switch off wind completely.twall11347243 said:So the 1MDa will give a gradient eventually even at 1g? It's just so small we can't detect it? Or is it saying that because it under 1um it settles so slowly we can't detect the gradient because there is no gradient. The context of this excerpt is talking about 1g. It's not talking about in an ultracentrifuge.
mfb said:Everything will give a non-zero gradient if you wait long enough. Even oxygen and nitrogen in the atmosphere would have a tiny gradient if we would switch off wind completely.
That does not mean it is relevant. The gravitational force of Pluto on us is non-zero as well, but completely irrelevant, for example.
Living cells are never in equilibrium (that is one of the key points of life), which makes this hypothetical situation even more pointless.
Diffusion is the process by which particles move from an area of higher concentration to an area of lower concentration, leading to a more even distribution of particles.
Sedimentation is the process by which particles settle at the bottom of a liquid due to the force of gravity.
At 1g, the force of gravity is equal to Earth's gravitational pull, causing particles to settle at the bottom of a liquid. This can affect the rate of diffusion, as the settling particles can create concentration gradients that hinder the movement of particles.
As the gravitational force increases, the speed of sedimentation also increases, causing particles to settle faster. However, the speed of diffusion remains relatively constant regardless of gravitational force, as it is driven by concentration gradients rather than gravity.
Understanding diffusion and sedimentation at 1g can be useful in industries such as pharmaceuticals, where the rate of diffusion can affect the distribution of medication in the body. It can also be used in environmental monitoring to track the movement of pollutants in water bodies.