ABSTRACT
Mitochondria are one of the important organelle of the cellular systems with double membrane present endosymbiotic in most eukaryotic cells. They are considered as a driving force in evolution and also called as heart generator of eukaryotic cells due to their hallmark ability to produce ATP through respiration. It is a specialized organelle in which utilization of oxygen occurs by means of energy extraction. In the evolution of eukaryotic cells they played a pivotal role by efficiently catalysing the ATP production via oxidative phosphorylation. Evolutionary theory suggests that at the initial stages of life on earth, the atmosphere consisted of only highly reduced molecules like NH3, H2O and H2. At that time anaerobic substances dominated on the earth. These anaerobic substances were used to extract energy by various anaerobic metabolisms like fermentation and glycolysis. Around 2.5 billion years ago a new kind of organism appeared that carried out a different type of metabolism in which two water molecules were added on and split oxygen to give rise to one single oxygen (O2) molecule (Fischer, 2008). This phenomenon brought a dramatic change on the life on earth. With passing time species began to arise which carried out several metabolic pathways to utilize molecular oxygen. This species are known as aerobes that eventually gave rise to all the aerobic prokaryotes and eukaryotes (Fischer, 2008). In eukaryotes, the utilization or extraction of oxygen occurs in mitochondria. This chapter highlights the fundamental aspects of structure-function features of mitochondria alongside in-depth survey of recent findings on the evolutionary facets of mitochondria.
