(A) Archaezoan hypothesis. (B) Symbiotic hypothesis. The shapes within the eukaryotic cell denote the nucleus, the endomembrane system, and the cytoskeleton. The irregular gray shape denotes a ...

The other type of hypothesis involves "autogenous" formation of internal membranes from only one non-eukaryote cell type via an infolding of cytoplasmic membrane to form an endomembrane system and ...