Why is the citric acid cycle a cyclic pathway rather than a linear pathway? in the oxidation of pyruvate to acetyl coa, one carbon atom is released as co2. however, the oxidation of the remaining two carbon atoms—in acetate—to co2 requires a complex, eight-step pathway—the citric acid cycle. consider four possible explanations for why the last two carbons in acetate are converted to co2 in a complex cyclic pathway rather than through a simple, linear reaction. use your knowledge of the first three stages of cellular respiration to determine which explanation is correct.