מידור איקריוטי

Eukaryotic cells contain numerous membrane-bound organelles that allow specific cellular functions to occur in distinct microenvironments, protected from the cytoplasmic interior as well as the extracellular environment.

For instance, the nuclear pore complexes embedded within the nuclear envelope control transport of molecules in and out of the nucleus. This helps to maintain controlled conditions inside the nucleus to regulate critical processes, such as gene expression.

Furthermore, some proteins require an oxidative environment and must be isolated from the reductive cytosol. Such proteins are produced and chemically modified within the endoplasmic reticulum before being transported to their final destinations via small chemical microcosms called vesicles.

Other organelles, such as peroxisomes, provide protection by sequestering enzymes that convert their own toxic byproducts, like hydrogen peroxide, into harmless molecules, such as water.

Similarly, lysosomes segregate digestive enzymes that function at a very low pH from the cytosol.

The acidic environment between the two membranes of a mitochondrion helps to produce energy in the form of ATP.

Overall, eukaryotic compartmentalization supports actions that would otherwise be incompatible if carried out simultaneously without some form of containment.