Answer :
The electron transport chain is the final and most important step of cellular respiration. While glycolysis and the citric acid cycle produce the necessary precursors, the electron transport chain is where the majority of ATP is created.
It is a stepwise process of cellular respiration that is responsible for producing:
1. water (with the help of the oxygen we breath)
2. up to 34 ATP molecules
3. NAD and FAD (which are recycled to be used again in the TCA cycle and glycolysis.)
The electron transport chain takes place in the mitochondria of eukaryotes and cell membrane of prokaryotes.