Endomembrane System

The endomembrane system is a useful organising concept rather than a single physical structure: it is the collective name given to the group of internal membranes within a eukaryotic cell that are functionally and developmentally linked to one another - specifically the plasma membrane, the nuclear membrane, the endoplasmic reticulum, the Golgi apparatus, the lysosomes, and the vacuolar membrane (tonoplast). All of these membranes share a common chemical architecture, built from phospholipids with proteins embedded in them, essentially the same basic construction as the plasma membrane itself, and they are all found within the cytoplasm. Evolutionarily, the whole system is thought to have originated from inward growths of the outer cell membrane in the very earliest eukaryo …