The presence of a nucleus is one major difference between eukaryotes and prokaryotes. Some conserved nuclear proteins between eukaryotes and prokaryotes suggest that these two types had a common ancestor. Another theory behind nucleation is that early nuclear membrane proteins caused the cell membrane to fold and form a sphere with pores like the nuclear envelope. As a way of forming a nuclear membrane, endosymbiosis could be expected to use less energy than if the cell was to develop a metabolic process to fold the cell membrane for the purpose. Digesting engulfed cells without energy-producing mitochondria would have been challenging for the host cell. On this view, membrane-bound bubbles or vesicles leaving the protomitochondria may have formed the nuclear envelope.
The presence of a nucleus is one major difference between eukaryotes and prokaryotes Some conserved nuclear proteins between eukaryotes and prokaryotes suggest that these two types had a common ancestor Another theory behind nucleation is that early nuclear membrane proteins caused the cell membrane to fold and form a sphere with pores like the nuclear envelope As a way of forming a nuclear membrane endosymbiosis could be expected to use less energy than if the cell was to develop a metabolic process to fold the cell membrane for the purpose Digesting engulfed cells without energy-producing mitochondria would have been challenging for the host cell On this view membrane-bound bubbles or vesicles leaving the protomitochondria may have formed the nuclear envelope