Question

What is the serial endosymbiotic theory? How does it explain the origin of mitochondria and chloroplasts?

Answer 1

Ancestors of Mitochondria were aerobic bacteria. Later process of endo symbiosis accommodated these in prokaryotic cells

Explanation:

Origin of cells earlier was anaerobic. Due to photosynthesis oxygen in earth environment increased. This gave rise to aerobic bacteria. Ancestors of mitochondria were aerobic bacteria. Scientists has found that ricketsia the trench fever bacteria and mitochondria genomes are similar. This shows that anaerobic prokaryotic cells engulfed aerobic bacteria. This increased ATP production of the cells. The process is known as endosymbiosis.