>>8464270

No, because I'm not mentally retarded.

>>8464280
Why would thinking that cells have synchronized transport capabilities confined to specific pathways be retarded?

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I think the better question is, do multi cellular animals the size of unicellular amoeba have a circulatory system and heartbeat?

Seriously, how does something this small even function?

>>8464287
Question are you asking if multi-cellular organisms with a bunch of tiny cells that combined equal the size of an amoeba have a circulatory system or if the amoeba itself have one?

What I'm thinking is that it might be related to the ability for a cell to grow large so the small multi-cellular might not have a good one but the amoeba would have a great one in order to circumvent the diffusion rate mandated by the squared cubed law.

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plants do kind of read cytoplasmic streaming

but at the cellular level everything is mostly powered by diffusion and concentration gradients.

>>8464298
If it were powered only by diffusion life would not be able to work. There are several different identified enzymes that function past the theoretical limit for diffusion and if you do the probability calculations for how long it should take to get the right tRNA's into position on a ribosome we would never be able to get proteins in under a minute but we get them in less then a second.

>>8464284

Because we know they don't.

>>8464314
Care to show me how we know?

>>8464317

Try opening an intro to cell biology textbook.

>>8464329
I've already gone through reference texts on the subject and read up on the latest literature. The method for inter cellular movement is ASSUMED to be diffusion but in reality is unknown. We only really know about how vesicles are transported and what tags on proteins and mRNA lead to what type of localization, the actual mechanism for localization is hand wavy at best. I finished cellular biology over a year ago and got a degree in biochemistry.

>>8464334
>degree in biochemistry.
bsc? or msc?

>>8464621
asking just out interest btw

>>8464627
Just a Bsc I'm going for a Ph.D program in biophysics. I didn't just say it as an "I'm so smart hur durr" just as an "I'm not entirely speaking out of my ass". I was hoping to get a discussion going on cellular transport or a least mechanisms and see if anyone has any good ideas.

>>8464754
I saw an animation a few months ago about somebody who had identified an intracellular cellular transport mechanism, it was a compound being 'walked' along a membrane. Sorry can't be more specific.

>>8465461
https://www.youtube.com/watch?v=y-uuk4Pr2i8

If there was a heartbeat, wouldn't we be able to tell? Not that circulation requires a beat.

>>8464300
I think the questions considered ITT are about a circulatory system in terms of gas exchange, nutrient delivery, etc. Protein folding and ligand binding (such as the tRNA example you mentioned) wouldn't be considered part of the discussion anyway, but they're reaction kinetics are not merely indicative of active transport. Proteins often reside in proximity to their active sites, binding to a ligand only when activated by some kind of trigger compound.

The more bizarre question is how a complex protein, comprised of hundreds of amino acids, can near-instantaneously assume the correct conformation; when there are effectively infinite other variations that if sampled one by one on the order of femtoseconds, would take more time than is available to our Universe. 2spoopy. Statistical mechanics does a decent job explaining it, but it's still mindblowing to me.

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>>8465461
Yeah that's specifically for vesicular transport though. This is myosin traveling along a micro-tubule. Th problem is that most things inside of cells aren't inside of membranes and are localized via diffusion which is difficult when considering a cell as a dilute liquid. In reality it is more like a dynamic jelly.

>>8465463
I'm thinking large numbers of nodes each with a specific frequency relating to which chemical reactions are taking place and the metabolic state. It wouldn't be coordinated enough to cause a single beat and instead would be more akin to a rain storm in a pool then a drop in a glass like a human heart.

>>8465509
The protein folding one is less interesting to me though because of the sheer number of different proteins involved in folding and restructuring bad proteins. Homeostasis is a big thing for life and cells have it down pretty well so being able to make sure an environment is just right to fold a necessary protein evolved from countless failures kinda makes sense to me. The actual physics of it occurring is mind blowing to me too though, I've been doing a lot of work in computational chemistry lately and it's crazy.

What you are saying is true and false int he first paragraph. You see protein folding and binding are both very precisely influenced by pH, temperature, hydration shell and proximity to other ions and molecules. Remember that water is never just water it is constantly transferring protons and making negatively and positively charged species that in still pure water are usually pretty evenly spread out throughout it. However as you add ions and the like into it the areas of H+ exchange form eddies and waves creating more complex micro climates meaning that even in perfectly neutral water acid and base chemistry can easily take place. In this regard a cell would feasibly require a system in place to regulate said climates otherwise proteins would not be able to fold properly. ie. a large number of connected nodes.

>>8465744
There are already examples of the cell trying to sequester proteins for proper folding in the ER and in Chaperonins that are literally huge proteins meant for holding smaller ones to force them to refold. There's like a strike system for proteins called ubiquitin that will send it to get refolded or destroyed if there are too many.

But how does attaching a tag cause a protein to reach its needed site fast enough to prevent major metabolic slow downs? My thought is these tags cause a downhill tilt in entropic and enthalpic conditions towards a certain spacial location in the cell where the specific molecule can be dealt with.

This is where conjecture comes in, as above so below. Multi-cellular organisms display a whole range of abilities and organs. These organs and abilities can usually be related back to the basic structure of a Eukaryotic cell. The brain-nucleus, digestive tract/ Lungs-lysosomes/mitochondria, Skin-membrane etc. So where would the heart and circulatory system be? The heart very well could be the Golgi body a hub of activity where various proteins and molecules are bundled up using trans-membrane proteins and then it is exported to one of a couple places. The circulatory system has been thought of as just the microtubules, actin and myosin. The only way things can travel through that stuff as we know is through myosin carrying large vesicles with the proper tags on it. Even then it's a little sketchy on how it decides which way to go, what if that is equivalent to saying that blood is only composed of red blood cells? It would explain how a cell is able to operate on the microscale for speed despite being just a bag of random ass chemicals thrown together and reacting completely randomly.