How does the electron transport chain work in cellular respiration?

Cellular respiration refers to the process in which glucose and other respiratory substrates are broken down to generate ATP (adenosine triphosphate), which are energy-carrying molecules. Cellular respiration consists of four main steps: glycolysis, pyruvate oxidation, the citric acid or Krebs cycle, and oxidative phosphorylation, which involves the electron chain transport. It is the last stage of the respiratory pathway and is the stage that generates the most ATP molecules. 

The electron transport chain (ETC) consists of a series of carrier proteins embedded in the inner mitochondrial membrane. The ETC accepts high-energy electrons donated by NADH (nicotinamide adenine dinucleotide) and FADH2 (flavin adenine dinucleotide) to generate a proton gradient. The proton gradient drives protons back into the mitochondrial matrix through ATP synthase. This flow of protons through ATP synthase facilitates the synthesis of ATP from ADP (adenosine diphosphate) and inorganic phosphate.