a) When C-1 of acetyl coA is labeled, why does half of the label end up in each of the carbons of succinate in the first turn of the cycle?

b) When C-1 of acetyl coA is labeled, why does none of the label come off until the second round?

c) When C-2 of acetyl coA is labeled, why does the label survive two full turns of the cycle but then become equally distributed among all four carbons of oxaloacetate by the end of the second cycle?

d) What if C-1 of the oxaloacetate were labeled instead, when would the label be released as CO2?