[Evolutionary origin of cell organelles]

A review on the evolutionary origin of the energy-yielding eukaryotic organelles is presented. Current autogenetic (endogenous compartmentalization) schemes, as well as different variants of symbiogenesis, are critically envisaged. A new symbiogenetic scheme is put forth, according to which mitochondria and chloroplasts originated divergently from a primordial photosynthetic organelle; the latter was acquired by endosymbiosis of ancient cyanobacteria in the cells of protoeukaryotes.