Glycolysis is part of

Options

A. Only anaerobic respiration
B. Krebs cycle
C. Only aerobic respiration
D. Both aerobic and anaerobic respiration.

Answer

**Step-by-Step Text Solution:**

1. **Understanding Glycolysis**: Glycolysis is a metabolic pathway that converts glucose into pyruvate, producing a small amount of ATP and NADH in the process. This pathway occurs in the cytoplasm of cells.

2. **Identifying the Role of Glycolysis**: Glycolysis is the first step in both aerobic and anaerobic respiration. It does not require oxygen to occur, which means it can function in both types of respiration.

3. **Pathways Following Glycolysis**:
- If oxygen is present (aerobic conditions), the pyruvate produced from glycolysis is further processed to enter the Krebs cycle (also known as the TCA cycle) and subsequently the electron transport chain.
- If oxygen is absent (anaerobic conditions), the pyruvate can undergo fermentation, leading to the production of either lactic acid (in muscles) or ethanol and carbon dioxide (in yeast).

4. **Conclusion**: Since glycolysis is the initial step that can lead to both aerobic and anaerobic respiration, it is accurate to say that glycolysis is part of both processes.

5. **Final Answer**: The correct option is "both aerobic and anaerobic respiration".

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