Does anaerobic respiration/fermentation require oxygen?

• A. Depends on organism
• B. No
• C. Only in plants
• D. Yes

Answer: (B)

The key idea is that these processes do not need oxygen to function. In fermentation, glycolysis provides a small amount of ATP, and NAD+ must be regenerated so glycolysis can continue. This happens by converting pyruvate into lactate (in animals) or into ethanol and CO2 (in yeast), which uses no oxygen. In anaerobic respiration, cells use electron transport chains just like in aerobic respiration, but with final electron acceptors other than oxygen—such as nitrates, sulfates, or carbon dioxide—so oxygen isn’t required. Oxygen can be present and some organisms will use aerobic pathways if it is available, but both fermentation and anaerobic respiration can operate without it.