Stage 1 is glycolysis which turns glucose into pyruvate (organic e- acceptor) and Stage 2 is Regeneration of NAD+ and the output is either 2 lactic acid & 2 ATP or 2 ethanol, 2 CO2, 2 ATP
How is NAD+ regenerated in fermentation?
NADH gives its electrons and H+ to pyruvate making NADH oxidized back to NAD+