In the endosymbiont theory, an engulfed prokaryote that could perform respiration evolved over the generations into mitochondria providing the cell with an efficient means of producing ATP from organic compounds.
Similarly, an engulfed prokaryote that could perform photosynthesis evolved over the generations into chloroplast providing the cell with sunlight-generated sugar.
Explanation:
Endosymbiosis is the mutual relationship between two organisms. The theory explains that eukaryotes have evolved from prokaryotic cell or organism.
The host eukaryotic cell engulfed bacteria or prokaryote as bacteria was once an independent entity which could perform cellular respiration and photosynthesis. Possibility of one more cell which engulfed other cells is there.
Mitochondria have its own DNA and is the centre of ATP production which suggests that mitochondria has evolved over the time by photosynthetic bacteria. Sequence analysis also suggest that mitochondria had evolved from eubacteria.
The bacteria integrated into plant cell able to perform photosynthesis has evolved in to chloroplast int the plant cells.
