The evolution of eukaryotic cells most likely involved ________.
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 theory of endosymbiosis proposes that mitochondria evolved from oxygen-using bacteria that were engulfed by larger bacterial cells. Over time, the bacteria evolved into mitochondria as they became integrated and interdependent with the host cell. This theory is supported by several lines of evidence, including similarities between the DNA and biochemistry of mitochondria and bacteria.

The Evolution of Eukaryotic Cells Most Likely Involved ________