Which metabolic pathway splits glucose into pyruvate, generating ATP and NADH in the cytosol?

• A. Krebs cycle
• B. Fermentation
• C. Glycolysis
• D. Electron transport chain

Answer: (C)

Glycolysis is the process that splits one glucose molecule into two pyruvate molecules in the cytosol, while producing ATP and NADH. It starts with a small energy investment but yields a net gain of two ATPs by substrate-level phosphorylation and two NADH molecules that carry electrons to later steps. The cytosolic location is key because glycolysis occurs in the aqueous cytoplasm, unlike the Krebs cycle and electron transport chain, which take place in mitochondria. Fermentation also happens in the cytosol but relies on pyruvate from glycolysis and mainly serves to regenerate NAD+ rather than splitting glucose itself. So the pathway described is glycolysis.