AP BIOLOGY

Detailed explanation-1: -In chemiosmosis, the energy stored in the gradient is used to make ATP. So, where does oxygen fit into this picture? Oxygen sits at the end of the electron transport chain, where it accepts electrons and picks up protons to form water.

Detailed explanation-2: -The end products of electron transport are NAD+, FAD, water and protons. The protons end up outside the mitochondrial matrix because they are pumped across the cristal membrane using the free energy of electron transport.

Detailed explanation-3: -Thus, oxygen’s role is to drive the entire set of ATP-producing reactions within the mitochondrion by accepting “spent” hydrogens. Oxygen is the final electron acceptor, no part of the process-from the Krebs Cycle through the electron transport chain-can happen without oxygen.

Detailed explanation-4: -Ultimately, chemiosmosis or ATP synthesis occurs at complex V or ATP synthase via an endergonic reaction induced by the electrochemical gradient, resulting in the movement of protons through the ATP synthase (complex V) into the mitochondrial matrix, and transferring an inorganic phosphate to ADP.