Which molecules are required for the electron transport chain to function?

The electron transport chain (ETC) is a critical component of cellular respiration, specifically occurring in the inner mitochondrial membrane. This process relies primarily on the presence of reduced electron carriers, NADH and FADH2, which are produced during earlier stages of cellular respiration, such as glycolysis and the Krebs cycle.

NADH and FADH2 serve as electrons donors, transferring electrons to the protein complexes in the ETC. As these electrons pass through the complexes, energy is released, which is then used to pump protons (H+) across the mitochondrial membrane, creating a proton gradient. This ultimately drives ATP synthesis via ATP synthase.

While oxygen is indeed essential as the final electron acceptor in the chain, it does not participate as a direct component of the molecules preceding the electron transport chain. Instead, oxygen's role is to combine with the electrons and protons to form water, thereby facilitating continuous electron flow through the chain. Hence, while oxygen is vital, it is not categorized as a primary molecule required for the normal functioning of the transport chain in the same way that NADH and FADH2 are.

Carbon dioxide is produced as a waste product during cellular respiration and does not play a role in the electron transport