The Most Likely Ancestor for Today's Mitochondria According to the Endosymbiotic

Question

The most likely ancestor for today's mitochondria according to the endosymbiotic model is a(n)
A) species in the genus Bacillus.
B) rickettsia.
C) member of the clostridia.
D) enterobacterium related to Escherichia coli.
E) cyanobacterium.

Accepted Answer

The endosymbiotic model suggests that mitochondria evolved from free-living bacteria that were engulfed by a host cell and established a symbiotic relationship. The most likely ancestor for mitochondria is believed to be a species of Rickettsia, a genus of gram-negative bacteria that are obligate intracellular parasites. This is supported by both genetic and morphological evidence.