Can you explain the endosymbiotic theory of the origin of eukaryotic cells?
The endosymbiotic theory addresses the origins of certain intracellular organelles. Both mitochondria (animals and plants) and chloroplasts (plants) have strucutres that resemble those of bacteria. It has been hypothesized that early on in eukaryotic evolution that an phagocytised bacterial cell somehow evaded digestion and survived in a symbiotic relationship inside the eukaryotic cell. After many millions of years, the internalized bacteria eventually became an integral part of the eukaryotic cell.
