Final answer:
Water is created in cellular respiration when O2 receives electrons and takes H+ from NADH, facilitated by the electron transport chain where energy from NADH and FADH2 is used to ultimately produce ATP and reduce oxygen to water.
Step-by-step explanation:
Water is created during cellular respiration when O2 receives electrons and takes H+ from the NADH. The electrons that eventually reduce oxygen to water come from both NADH and FADH2 that are produced during different stages of cellular respiration. Through a series of reactions in the electron transport chain, the high-energy electrons derived from these molecules are transferred sequentially through a series of protein complexes, ultimately reaching oxygen, which becomes reduced to water.
During aerobic cellular respiration, the final electron acceptor is an oxygen molecule, O2. The process involves oxidative phosphorylation, where ATP is produced by the electron transport chain using the energy of high-energy electrons carried by NADH or FADH2. The culmination of this electron transfer is the reduction of oxygen and the formation of water within the mitochondria of the cell.