Answer:
It is easier to remove electrons and produce CO2 from compounds with three or more carbon atoms than from a two-carbon compound such as acetyl CoA.
Explanation:
Since the two-carbon acetyl group of acetyl CoA can be oxidized to two molecules of CO2, attaching the acetyl group to a four-carbon acid to produce a six-carbon acid is much more complicated (citrate). Citrate can then be oxidized in a series of reactions to produce two molecules of CO2.
