Comment on Smöl
MotoAsh@piefed.social 14 hours agoNah. You are assuming a red blood cell is a common size. It’d be like aliens coming to Earth, seeing Humans, and assuming life’s average scale is that of a human on this planet.
There is a MASSIVE scale of difference between cells of different animals. Some cells can be seen with the naked eye. That doesn’t magically mean other animal cells have to also be large.
There are entire living organisms that are smaller than Titin. Several species of eukaryotes are smaller than Titin, and they’re single celled orgsnisms by definition. A single celled organism smaller than a human blood cell by an order of magnitude.
That says nothing of prokaryotes, which are also celled organisms that are multiple orders of magnitude smaller still.
Again, it’s amazing only because you assume humans aren’t fucking insanely huge. An understandable perspective for sure, but a wrong perspective none the less.
drosophila@lemmy.blahaj.zone 12 hours ago
I mean, correct me if I’m wrong, but IIRC cell size is mostly determined by the necessary rate of diffusion across the membrane.
So, while their are some extreme outliers with more exotic cell biology, organisms having similar cellular metabolisms (e.g. both being in the animal kingdom) will generally have similarly sized cells. Or in other words, an elephant is much larger than an ant because it has many more cells, not because its cells are much larger.
An exception to this of course being neural cells, which can be very very long, or very wide and branched (like Purkinje cells). But even within the brain this still kinda holds true. I actually know much more about brain anatomy than general biology, and I remember from the book Principles of Brain Evolution that elephant brains are much larger than ours, and actually have a much larger number of neurons, and that strangely intelligence seems to correlate more with the ratio between brain and body size than with absolute brain size. A possible explanation is that it may simply take a larger number of neurons to control a larger number of muscle cells.
MotoAsh@piefed.social 8 hours ago
Definitely wrong, although I do not have a collegiate off-hand understanding of biology to really full decribe it.
But it comes down to what does a “cell” mean in biology? Even your case in point specifies an object with many cells in it.
Cell membranes don’t use simple diffusion to transport chemicals across. That’s the entire point of a “cell”. It’s a defined region that at least attempts to control its own various chemical balances. Cells do have many gates that allow many molecules across, unfortunately including many viruses and prions.
drosophila@lemmy.blahaj.zone 4 hours ago
Well, from reading this its pretty clear to me that you don’t know much about biology. And yet you have really strong opinions on something you have no education in.
What are you even trying to say here?
The word “diffusion” is pretty commonly used to refer to both active and passive transport, and the ratio of cytoplasm volume to cell membrane area is relevant regardless.
en.wikipedia.org/wiki/Facilitated_diffusion
By the way, you didn’t need to write an entire paragraph about homeostasis or try to define what a cell is.
Your perspective really comes across like you’re high on something. You also didn’t understand what my comment was even about.