A biochemist studies the fate of pyruvate in four different cell types (A-D). She incubates each cell with
1-14C-pyruvate and measures the ATP content and the radioactive carbon dioxide, ethanol, and lactic acid produced in each cell type. She repeats the experiment using 2-14C-pyruvate, which is a measure of Krebs cycle activity. The results are shown in the graphs.
In Cell D, which process completely oxidizes pyruvate?
a) Krebs cycle
c) alcoholic fermentation
d) lactic acid fermentation