Work Step by Step
Glycerol is a three carbon compound like those which appear in glycolysis after glucose is broken down, so glycerol could conceivably be fed into the overall process of glucose breakdown by cellular respiration at that point. Mutations in the genes for enzymes which come before glucose is broken into three-carbon molecules would not stop mutant yeast from growing on glycerol (A.). B. is wrong since glycerol cannot feed directly into the Krebs cycle, which accepts two-carbons at a time, not three, and C. can be eliminated since fermentation would not be needed according to the conditions in the question, which say nothing about a lack of oxygen. Also, continuing with cellular respiration from glycerol would yield much more energy, which makes more sense if there is not a lack of oxygen. D. is wrong since electrons do not go from a three-carbon molecule to the electron transport chain.