In aerobic respiration, molecular oxygen's task within the electron transport chain is to serve as the...

Core Concept

Electrons descend the transport chain from carrier to carrier, losing energy at each complex until they reach the end. Oxygen, with its strong attraction for electrons, accepts them at complex IV along with protons from the matrix. The reaction yields water, which safely removes electrons from the system. Without this drain, backed-up electrons would halt the entire chain and stop ATP production.