serial endosymbiosis theory
Quick Summary
The serial endosymbiosis theory (SET) proposes that eukaryotic organelles, like mitochondria and chloroplasts, originated from prokaryotic organisms that were engulfed by other prokaryotes. This process involved sequential symbiotic events where the engulfed organisms were incorporated into the host cell, eventually losing their independent existence and becoming organelles. Mitochondria, responsible for energy production, are thought to have originated before chloroplasts, which are involved in photosynthesis. This theory is a cornerstone in understanding the evolution of complex eukaryotic cells.123
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