Which of the following processes is included in fermentation?

• A. Glycolysis
• B. Electron transport chain
• C. Citric acid cycle
• D. Oxidative phosphorylation

Answer: (A)

Verified step by step guidance

1. Understand the concept of fermentation: Fermentation is an anaerobic process (does not require oxygen) that allows cells to produce energy in the absence of oxygen. It primarily involves glycolysis followed by reactions that regenerate NAD⁺.
2. Review glycolysis: Glycolysis is the first step in cellular respiration and occurs in the cytoplasm. It breaks down glucose into two molecules of pyruvate, producing ATP and NADH. This step is common to both aerobic and anaerobic respiration, including fermentation.
3. Exclude processes requiring oxygen: The electron transport chain, citric acid cycle, and oxidative phosphorylation are all part of aerobic respiration and require oxygen. These processes are not included in fermentation.
4. Focus on NAD⁺ regeneration: In fermentation, after glycolysis, NADH is converted back to NAD⁺ to ensure glycolysis can continue. This occurs through pathways like lactic acid fermentation or alcoholic fermentation, depending on the organism.
5. Conclude that glycolysis is the correct answer: Glycolysis is the only process listed that is part of fermentation, as it is the initial step that provides ATP and sets the stage for NAD⁺ regeneration in anaerobic conditions.