Final answer:
The first metabolic intermediate common to aerobic metabolism of glucose and fatty acids (via beta-oxidation) is acetyl CoA. This molecule undergoes further metabolism in the Krebs cycle to produce ATP.
Step-by-step explanation:
The first metabolic intermediate common to aerobic metabolism of glucose and fatty acids (via beta-oxidation) is acetyl CoA. In the breakdown of fatty acids, fatty acyl CoA is converted to acetyl CoA through a series of reactions, including the beta-oxidation pathway. Acetyl CoA then enters the Krebs cycle, where it is further metabolized to produce ATP. This process allows both glucose and fatty acids to be used as sources of energy in aerobic metabolism.