Here's a breakdown:
* Glucose is broken down: In glycolysis and the citric acid cycle, glucose is broken down, and electrons are removed from its carbon atoms.
* Electron carriers: These electrons are picked up by electron carriers, NAD+ and FAD, which become reduced to NADH and FADH2.
* Electron transport chain: NADH and FADH2 deliver the electrons to the electron transport chain, a series of protein complexes embedded in the mitochondrial membrane.
* Oxygen as the final electron acceptor: The electrons move down the chain, losing energy along the way. This energy is used to pump protons across the mitochondrial membrane, generating a proton gradient. Finally, the electrons are passed to oxygen, which is the final electron acceptor.
* Water formation: Oxygen combines with the electrons and protons to form water, which is a byproduct of cellular respiration.
In essence, the electrons stripped from glucose ultimately end up being used to reduce oxygen to water, a process that releases a significant amount of energy used by the cell.
