Which of the following is the best definition of fermentation?

• A. A process in which cells use nitrate as a final electron acceptor instead of oxygen.
• B. A process that uses oxygen to completely oxidize glucose to carbon dioxide and water.
• C. An anaerobic process in which cells convert glucose into energy and produce organic end products such as lactic acid or ethanol.
• D. The breakdown of glucose in the presence of light to produce ATP and oxygen.

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the term 'fermentation'. Fermentation is a metabolic process that occurs in the absence of oxygen (anaerobic conditions) and allows cells to generate energy by breaking down glucose or other organic molecules.
2. Step 2: Identify the key characteristics of fermentation. It involves the partial oxidation of glucose, resulting in the production of energy (ATP) and organic end products such as lactic acid (in lactic acid fermentation) or ethanol and carbon dioxide (in alcoholic fermentation).
3. Step 3: Analyze the provided options. Eliminate choices that do not align with the definition of fermentation. For example, processes involving oxygen (aerobic respiration) or light (photosynthesis) are not fermentation.
4. Step 4: Focus on the correct option. The correct definition of fermentation is 'An anaerobic process in which cells convert glucose into energy and produce organic end products such as lactic acid or ethanol.' This matches the characteristics of fermentation discussed earlier.
5. Step 5: Conclude by reinforcing the concept. Fermentation is crucial for organisms that live in environments lacking oxygen, and it allows them to produce energy efficiently under anaerobic conditions.