Where does pyruvic acid go when oxygen is available?

When oxygen is available, pyruvic acid enters aerobic respiration. This process begins with the conversion of pyruvic acid, which is produced during glycolysis, into acetyl CoA before entering the Krebs cycle.

In the presence of oxygen, this metabolic pathway allows for the complete oxidation of glucose, maximizing ATP production. During aerobic respiration, pyruvic acid is transported into the mitochondria, where it undergoes further processing. In contrast, if oxygen were not available, pyruvic acid would enter fermentation pathways instead, which are less efficient and do not fully oxidize the energy stored in glucose.

Thus, aerobic respiration is the correct pathway for pyruvic acid when oxygen is available, ensuring that energy is extracted efficiently.