The electron transport chain (ETC) consists of a series of 4 protein complexes embedded in the inner mitochondrial membrane. The ETC plays a crucial role in cellular respiration, specifically in the final stage known as oxidative phosphorylation. 

During the process of oxidative phosphorylation, electrons are transferred through the electron transport chain, creating an electrochemical gradient that results in the generation of ATP (adenosine triphosphate). The electron transport chain is essential for producing the majority of ATP, which is the cell’s main energy currency in aerobic organisms.