Okay, another important concept.
The membrane proteins that are in this lipid bilayer can also provide cellular structure.
So, at the top, we have a red blood cell. Red blood cells are biconcave disc.
Meaning that they're concave on one side and concave on the other side.
The way I think about them is I take a jelly donut and I squish it in the middle.
That's a red cell.
And it has that confirmation so that it is maximally flexible as it goes through capillaries.
Turns out that's the best structure for a red cell.
It also provides enough surface area because of the extra indentation for the cells to provide oxygen
to give enough surface area so they get the best transport
and diffusion of oxygen out of the red cell and into the tissues.
So, it has a couple different reasons.
This red cell, it's kind of like we've opened the glove compartment on the car.
So, we're just kind of taking a flap and opened it
and we're looking below at the interface of the membrane of that red cell.
And in that interface, we see that there a number of transmembrane proteins
and then, there are a bunch of other kind of squiggly lines going in between.
Again, the names are not too important. I's the concept here.
So, we have these transmembrane proteins.
It includes anion channels and glycophorin A.
Again, don't get bogged down with the names.
They're just there but then, we have the linker proteins between them, actin and ankyrin
and then, another linker protein, spectrin,
and these additional molecules, the actin and the spectrin, and ankyrin
are going to give the red cell its biconcave, squished jelly donut configuration.
They are holding it in that configuration.