What molecules are formed at the end of the electron transport chain?

At the end of the electron transport chain, ATP and water are produced as the primary products. The electron transport chain is the final stage of cellular respiration, occurring in the inner mitochondrial membrane. During this process, electrons from electron carriers like NADH and FADH2 are passed through a series of protein complexes. As the electrons move through these complexes, energy is released and used to pump protons (H+) across the membrane, creating a proton gradient.

This gradient is utilized by ATP synthase, an enzyme that synthesizes ATP as protons flow back across the membrane. In addition to ATP, oxygen plays a crucial role as the final electron acceptor in the chain. When electrons combine with oxygen, they form water, completing the process. Therefore, at the conclusion of the electron transport chain, the significant products are ATP and water, supporting energy production in the cell.

This outcome distinguishes the correct answer from the others, which either describe different stages of cellular respiration or are products from fermentation processes rather than from the electron transport chain.