Can someone describe the structure of the membrane of organelles?
Do they also have protein channels, etc.?
Also, is ribosome referred to a non-membrane bound organelle because it does not have a phospholipid bilayer? If so, what is the membrane of ribosome like?
Thanks!
The structure of organelle membranes is pretty different to that of the cell itself, but in a very broad stroke, they are essentially the same kind of thing. Phospholipid and whatnot, most will have protein channels though it does depend on the organelle. FOr example, you should already have some insights into the membrane of most of the organelles you've already encountered. A little bit of a recap:
Nucleus: bilayer that folds in on itself to make pores.
Mitochondria: internal and external membranes, lots of membrane proteins particularly in the internal membrane (think ETC). Naturally, there are channels/carriers on the external membrane to let proteins in and out
Chloroplast: similar story to mitochondria, two membranes (gram -), thylakoids on the inside
ER: pretty similar to cell, though studied with ribosomal complexes
Golgi: practically identical to the cellular membrane. Pretty much all golgi membrane eventually becomes cell membrane anyway, so they have to be very similar. Although, the membrane in the Golgi actually undergoes changes, becoming more and more structurally similar to the cell as it gets closer to budding off.
Ribosomes don't have a membrane at all. They're just a big hunk of protein and rRNA