What molecule is not required by fermentation?Group of answer choicesglucoseoxygenNADHpyruvateAll of the above are required by fermentation reactions

To determine which molecule is not required by fermentation, let’s analyze each option within the context of the fermentation process.

1. Glucose: This is a key substrate for fermentation. Microorganisms break down glucose to produce energy in the absence of oxygen, so glucose is indeed required.

2. Oxygen: Fermentation occurs in the absence of oxygen. In fact, fermentation is a type of anaerobic respiration, meaning that oxygen is not needed. Thus, oxygen is not required for fermentation.

3. NADH: This molecule is generated during glycolysis when glucose is broken down. It plays an important role in fermentation as it is oxidized back to NAD⁺, allowing glycolysis to continue. Therefore, NADH is required.

4. Pyruvate: Pyruvate is the end product of glycolysis and serves as a substrate for fermentation pathways (like lactic acid fermentation and alcoholic fermentation). Thus, pyruvate is required.

5. All of the above are required by fermentation reactions: This option implies that all mentioned substances are necessary for fermentation, which is incorrect because of the presence of oxygen.

Conclusion

Based on the analysis, the molecule that is not required by fermentation is oxygen.