- A ATP generated by the electron transport chain
- B NADH produced earlier during glycolysis
- C CO2 released from the Krebs cycle reactions
- D Oxygen drawn in from the surrounding air
Correct answer: B. NADH produced earlier during glycolysis
Explanation: In lactic acid fermentation, pyruvate accepts electrons from NADH (generated during glycolysis) and is reduced to lactic acid, regenerating NAD+ for glycolysis to continue.
Concept context
Glycolysis, the Krebs cycle, the electron transport chain, fermentation, and the respiratory quotient. The cellular energy-release counterpart to photosynthesis.