If you have three pyruvate molecules each labeled with 14C at different positions (one is labeled at the carboxyl, one at the carbonyl, and one at the methyl), feed them sequentially to pyruvate dehydrogenase and the citric acid cycle, starting with the one labeled at the carboxyl take that to oxaloacetate, then follow with the one labeled at the carbonyl all the way to oxaloacetate keeping track of both 14C labels, and lastly the one labeled at the methyl..keeping track of all 3 14C labels. In the end, in what molecule(s) and at what position would the label reside when finished? If liberated as carbon dioxide, what step? Show work (on additional sheet(s) of paper, if necessary).