What is the fate of the radioactive label when each of the
following compounds is added to a cell extract containing the
enzymes and cofactors of the glycolytic pathway, the citric acid
cycle and the pyruvate dehydrogenase complex? You only have to go
through the citric acid cycle once, if the label is still present,
indicate which carbon(s) in oxaloacetate contain the label.

a) glucose-6-phosphate labeled at C-4

b) pyruvate labeled at C-2