Question

During the origin of the eukaryotic cell, it is thought that engulfed bacteria ?

a. were always harmful to their hosts.

b. always had a mutually beneficial relationship with their hosts.

c.had a mutually beneficial relationship with their hosts initially, but later evolved to become harmful to their hosts.

d.vdid not initially have a mutually beneficial relationship with their hosts, but later evolved one.

Answer 1

Answer D) did not initially have a mutually beneficial relationship with their hosts, but later evolved one.

Reason- As we know that prokaryotes and eukaryotes are two different kinds of cells. eukaryotes contain much more complex cellular system than prokaryotes. but the eukaryotic mitochondrial genome has high degree of similarity with the bacterial genome and its machinery. it is thought that Eukaryotes arise as a result of engulfment of bacteria. in such case, bacteria must be present as independent and free-living cells. however, engulfment by other cell resulted into development of mutual benefits. further this mutually beneficially relationship was evolved and stabilized in the course of evolution.

Therefore, bacteria must be living freely and have no mutually beneficial relationship initially with their hosts, but should be later evolved one.