An early step in the evolution of eukaryotic cells most likely involved which of the following events?
A) endosymbiosis of an oxygen-using bacterium in a larger bacterial host cell-the endosymbiont evolved into chloroplasts
B) endosymbiosis of a photosynthetic archaeal cell in a larger bacterial host cell to escape toxic oxygen-the anaerobic archaea evolved into chloroplasts
C) endosymbiosis of an oxygen-using bacterium in a larger bacterial host cell-the endosymbiont evolved into mitochondria
D) evolution of an endomembrane system and subsequent evolution of mitochondria from a portion of the smooth endoplasmic reticulum

Question

Quizplus · Accepted Answer

The endosymbiotic theory suggests that mitochondria originated from the engulfment of an aerobic bacterium by a larger host cell. This event is believed to be a critical step in the evolution of eukaryotic cells, allowing them to utilize oxygen for energy production more efficiently.

An Early Step in the Evolution of Eukaryotic Cells Most