5 ms·

Awesome images, thanks for sharing. I wish they'd have put these in science books growing up. Are these to scale? It's interesting to see how much more particu

by jmole 8y ago

Awesome images, thanks for sharing. I wish they'd have put these in science books growing up. Are these to scale? It's interesting to see how much more particular (as in, composed of large particles) these cells look compared to the illustrations I'd seen growing up. I always imagined the proteins that made up a cell wall would be more on the order of how grass looks to a human, in terms of size respective to the cell. Or another analogy, I used to think of a cell like a room (the cell membrane) with furniture in it (the organelles). Now it seems more like just a big pile of furniture.

improbable22 8y ago
Another famous example: The magic of the Golgi stain, which first produced pictures of neurons, was that it stained only a tiny fraction of the cells. That's why you can obtain a picture with cells reaching out and occasionally connecting. Whereas in reality all that empty space is other cells, doing the same thing. More modern pictures are like so: http://www.conte.harvard.edu/news/2015/8/18/imaging-the-brains-jungles-a-miniscule-yet-monumental-leap-forward http://www.conte.harvard.edu/news/2015/8/18/imaging-the-brai...
entee 8y ago
I believe the components are indeed drawn to scale! The cell is a mess, there is virtually no central coordination, just individual molecular signals. A protein gets phosphorylated by a receptor, then its on its merry way till it hits something it interacts with and maybe because it's phosphorylated it activates that thing to do something else, or maybe, luck of the draw it doesn't. It's amazing that it even works, but it does so because billions of years have shaped life to be resilient to chaos. Some context: Unicellular life is roughly 3.5B years old Eukaryotic life is roughly 2B years old. It took 1.5B years to figure out how to build and use organelles Multicellular life is roughly 1B years old. Another billion years to figure out how to coordinate and specialize cells. Sea sponges, essentially "animals" are 700M years old Animals that can move around are about 500-600M years old, backbones in animals show up around the same time, then we're off to the races. This sort of patterning is maybe in the 700-800M year old window. It took billions of years for life to figure this out, you can do a lot by evolving that long. https://www.newscientist.com/article/dn17453-timeline-the-evolution-of-life/ https://www.newscientist.com/article/dn17453-timeline-the-ev...
- est31 8y ago
  > A protein gets phosphorylated by a receptor, then its on its merry way till it hits something it interacts with and maybe because it's phosphorylated it activates that thing to do something else, or maybe, luck of the draw it doesn't. There are proteins that spread via diffusion, but there is also transport along microtubules in transport vesicles. Not entirely sure how the routing/navigation question is solved though, aka how does some vesicle know it needs to go to the nucleus vs golgi apparatus.
  - entee 8y ago
    Oh yes, of course there are many motorized processes, but the point is there's no inherent logic to them. A myosin grabs onto a filament and goes to the plus end of the actin filament (usually, not some of them, again it gets complicated :) but it doesn't know where that tube is going. It'll just happily move to the end and fall off/get blocked. If the destination "wants" or "needs" supra-diffusion transport, it needs to recruit the tubes to come to it. Every entity in the cell essentially acts as its own agent, and it's only through interactions that it does one thing or another. EDIT: probably more accurate to call actin "filaments" not tubes, typo
    - rrock 8y ago
      Actually, there’s quite a bit of inherent logic to actomyosin traffic networks, as we’re now beginning to discover. For example, myosin 10 has evolved to walk along specific bundles of actin, but not so well along single actin filaments. The bundle has mechanical integrity and leads to a distant location in the cell, and the myosin 10 can detect that the actin is bundled. So in some sense it knows that it is walking along the right structure that leads to that distant location. There are some other examples, but this is all at the cutting edge of motility research.
Pulcinella 8y ago
I believe they are roughly to scale. I remember reading how Goodsell does some back of the envelope calculations when planning an illustration. You hear in pop-science how the human body is ~50-70% water as if that is a lot. Really it’s a rather low level of solvent to run chemistry reactions in. I did some undergraduate research in a biochemistry lab and when we would perform an experiment with a protein we were studying, the proteins and other chemicals would always be very dilute, maybe ~99.9999% water or higher. Cells are very “sludgy” and it’s surprising to me that anything works at all the proteins don’t just immeadietly stick together and precipitate out of solution like egg-whites when cooked. It’s a tricky number to estimate because the orders of magnitude are so stark. Proteins are at very, very low concentrations but each protein is made of hundreds or thousands of atoms. The number of protein molecules is small but the they are almost big enough that their volume is not insignificant. There are other things that are unintuitive about chemical reactions. A lot of chemical reactions are faster than the movement of molecules. A protein maybe able to catalyze a chemical reaction faster than it can diffuse through water so it sits around most of the time waiting to collide with the molecule it will catalyze. Basically like a CPU waiting an eternity for data from a “fast” SSD to show up.
- a1369209993 8y ago
  > You hear in pop-science how the human body is ~50-70% water as if that is a lot. Really it's a rather low level of solvent to run chemistry reactions in. For reference, gelatin is about 85% water[0], and still manages to be a solid glob you can balance utensils on top of. 0: The stuff I had on hand is 20g powder to 118g water.
781 8y ago
Cells are extremely crowded. In fact, some processes like protein folding require crowdiness, if it's missing it can misfold. Realistic animation: http://www.cellimagelibrary.org/images/28234 http://www.cellimagelibrary.org/images/28234
- Ultimatt 8y ago
  Also worth keeping in mind just how fast the motion really is. That whole clip happens in 15 micro seconds.

by jmole 8y ago

improbable22 8y ago

Another famous example: The magic of the Golgi stain, which first produced pictures of neurons, was that it stained only a tiny fraction of the cells. That's why you can obtain a picture with cells reaching out and occasionally connecting. Whereas in reality all that empty space is other cells, doing the same thing. More modern pictures are like so: http://www.conte.harvard.edu/news/2015/8/18/imaging-the-brains-jungles-a-miniscule-yet-monumental-leap-forward http://www.conte.harvard.edu/news/2015/8/18/imaging-the-brai...

entee 8y ago

I believe the components are indeed drawn to scale! The cell is a mess, there is virtually no central coordination, just individual molecular signals. A protein gets phosphorylated by a receptor, then its on its merry way till it hits something it interacts with and maybe because it's phosphorylated it activates that thing to do something else, or maybe, luck of the draw it doesn't. It's amazing that it even works, but it does so because billions of years have shaped life to be resilient to chaos. Some context: Unicellular life is roughly 3.5B years old Eukaryotic life is roughly 2B years old. It took 1.5B years to figure out how to build and use organelles Multicellular life is roughly 1B years old. Another billion years to figure out how to coordinate and specialize cells. Sea sponges, essentially "animals" are 700M years old Animals that can move around are about 500-600M years old, backbones in animals show up around the same time, then we're off to the races. This sort of patterning is maybe in the 700-800M year old window. It took billions of years for life to figure this out, you can do a lot by evolving that long. https://www.newscientist.com/article/dn17453-timeline-the-evolution-of-life/ https://www.newscientist.com/article/dn17453-timeline-the-ev...

est31 8y ago
> A protein gets phosphorylated by a receptor, then its on its merry way till it hits something it interacts with and maybe because it's phosphorylated it activates that thing to do something else, or maybe, luck of the draw it doesn't. There are proteins that spread via diffusion, but there is also transport along microtubules in transport vesicles. Not entirely sure how the routing/navigation question is solved though, aka how does some vesicle know it needs to go to the nucleus vs golgi apparatus.
- entee 8y ago
  Oh yes, of course there are many motorized processes, but the point is there's no inherent logic to them. A myosin grabs onto a filament and goes to the plus end of the actin filament (usually, not some of them, again it gets complicated :) but it doesn't know where that tube is going. It'll just happily move to the end and fall off/get blocked. If the destination "wants" or "needs" supra-diffusion transport, it needs to recruit the tubes to come to it. Every entity in the cell essentially acts as its own agent, and it's only through interactions that it does one thing or another. EDIT: probably more accurate to call actin "filaments" not tubes, typo
  - rrock 8y ago
    Actually, there’s quite a bit of inherent logic to actomyosin traffic networks, as we’re now beginning to discover. For example, myosin 10 has evolved to walk along specific bundles of actin, but not so well along single actin filaments. The bundle has mechanical integrity and leads to a distant location in the cell, and the myosin 10 can detect that the actin is bundled. So in some sense it knows that it is walking along the right structure that leads to that distant location. There are some other examples, but this is all at the cutting edge of motility research.

Pulcinella 8y ago

I believe they are roughly to scale. I remember reading how Goodsell does some back of the envelope calculations when planning an illustration. You hear in pop-science how the human body is ~50-70% water as if that is a lot. Really it’s a rather low level of solvent to run chemistry reactions in. I did some undergraduate research in a biochemistry lab and when we would perform an experiment with a protein we were studying, the proteins and other chemicals would always be very dilute, maybe ~99.9999% water or higher. Cells are very “sludgy” and it’s surprising to me that anything works at all the proteins don’t just immeadietly stick together and precipitate out of solution like egg-whites when cooked. It’s a tricky number to estimate because the orders of magnitude are so stark. Proteins are at very, very low concentrations but each protein is made of hundreds or thousands of atoms. The number of protein molecules is small but the they are almost big enough that their volume is not insignificant. There are other things that are unintuitive about chemical reactions. A lot of chemical reactions are faster than the movement of molecules. A protein maybe able to catalyze a chemical reaction faster than it can diffuse through water so it sits around most of the time waiting to collide with the molecule it will catalyze. Basically like a CPU waiting an eternity for data from a “fast” SSD to show up.

a1369209993 8y ago
> You hear in pop-science how the human body is ~50-70% water as if that is a lot. Really it's a rather low level of solvent to run chemistry reactions in. For reference, gelatin is about 85% water[0], and still manages to be a solid glob you can balance utensils on top of. 0: The stuff I had on hand is 20g powder to 118g water.

781 8y ago

Cells are extremely crowded. In fact, some processes like protein folding require crowdiness, if it's missing it can misfold. Realistic animation: http://www.cellimagelibrary.org/images/28234 http://www.cellimagelibrary.org/images/28234

Ultimatt 8y ago
Also worth keeping in mind just how fast the motion really is. That whole clip happens in 15 micro seconds.