Answer:
To function as the final electron acceptor in the electron transport chain
Step-by-step explanation:
Cellular respiration is the process by which cells degrade food molecules to obtain energy in the form of Adenosine Triphosphate (ATP).
Respiration comprises the following steps:
Glycolysis (oxidation of glucose to pyruvate)
Acetyl-CoA formation.
Krebs cycle.
Electron transport chain and oxidative phosphorylation.
Glucose oxidation processes reduces NAD+ to NADH and FAD+ to FADH, these molecules accepts electrones produced when glucose is oxidized.
The electrons accepted by NADH and FADH then pass through a series of electron transporters, going from a high energy level to a lower one.
Finally, oxygen is the last electron acceptor, which combines with 2 protons (hydrogen ions) and forms water.