Definition of Endosymbiosis
Endosymbiosis is a symbiotic relationship that is formed by the engulfing of one cell by another which is larger in size. Both cells take benefits from each other. This relationship is thought to be first considered when the similarity between the chloroplasts and photosynthetic bacteria i.e. cyanobacteria was observed.
It has been deduced that the endosymbionts transfer some of their genetic material to the nucleus of the host cell. In this way, they start depending upon the host cell for their survival and other basic requirements.
Example of Endosymbiosis:
The mitochondria and chloroplasts became part of a eukaryotic cell as a result of endosymbiosis.