What is the Electron Transport Chain (ETC) and how does it help make ATP in cellular respiration?

Cellular Respiration is a three-step process. The Electron Transport Chain (ETC) is the final step of this process, generating majority of the ATP. The first two steps of Glycolysis and Citric Acid Cycle are just as important, as they help create an essential component of ETC, high energy electrons.

ETC is a collection of proteins attached to the inner membrane of the mitochondria, the ‘powerhouse’ of the cell. The high-energy electrons are passed down these proteins (electron acceptors), and energy generated through this process pumps Hydrogen molecules (H+) across the membrane, from the outer matrix to the inner mitochondria. There is a difference in the concentration of H+ molecules across the membrane that drives the whole mechanism. Return of H+ molecules back to the matrix side activates a special protein, ATP synthase, to rotate which helps put together ADP + Pi to generate ATP. Oxygen molecule is the final acceptor of H+ and electrons, forming water.

ATP is then used in the body to carry out processes essential for survival.