The Evolution of Eukaryotic Cells Most Likely Involved

Question

The evolution of eukaryotic cells most likely involved
A) endosymbiosis of an aerobic bacterium in a larger host cell-the endosymbiont evolved into mitochondria.
B) anaerobic archaea taking up residence inside a larger bacterial host cell to escape toxic oxygen-the anaerobic bacterium evolved into chloroplasts.
C) an endosymbiotic fungal cell evolved into the nucleus.
D) acquisition of an endomembrane system, and subsequent evolution of mitochondria from a portion of the Golgi.

Accepted Answer

The endosymbiotic theory proposes that eukaryotic cells evolved from the symbiotic relationships between different types of prokaryotic cells. The most widely accepted hypothesis is that an aerobic bacterium was engulfed by a larger host cell and eventually evolved into mitochondria. This is supported by several lines of evidence, such as the fact that mitochondria have their own DNA, which is similar to bacterial DNA, as well as their own ribosomes, which are similar to bacterial ribosomes. Additionally, the inner membrane of mitochondria contains enzymes and transport systems similar to those found in the plasma membrane of some bacteria. Overall, the endosymbiotic theory provides a plausible explanation for the origin of eukaryotic cells, as it accounts for the presence of organelles such as mitochondria and chloroplasts, which are believed to have originated from free-living prokaryotes.