Why is the citric acid cycle so complicated? Catabolic pathways modeling studies based on the activity of various oxidoreductase enzymes predict that the complete oxidation of an acetyl group to CO2 could be accomplished in as few as 4 enzyme catalyzed reactions, yet the citric acid cycle has 8 steps. So why, most likely, did the cycle evolve this way? Explain and give at least one specific example to make your argument.