Lactic acid is produced in the process of

Options

A. Fermentation
B. HMP
C. Krebs cycle
D. Glycolysis.

Answer

**Step-by-Step Solution:**

1. **Understanding the Processes**: First, we need to identify the metabolic processes mentioned in the question: fermentation, hexose monophosphate shunt (HMP), Krebs cycle, and glycolysis.

2. **Analyzing Fermentation**: Fermentation is an anaerobic process that occurs when oxygen is not available. It involves the conversion of carbohydrates, such as glucose, into energy. One of the byproducts of this process is lactic acid, especially in muscle cells during intense exercise.

3. **Examining the Other Processes**:
- **Hexose Monophosphate Shunt (HMP)**: This pathway primarily produces ribose-5-phosphate and NADPH, and does not produce lactic acid.
- **Krebs Cycle**: This cycle is an aerobic process that occurs in the mitochondria, producing carbon dioxide, ATP, NADH, and FADH2, but not lactic acid.
- **Glycolysis**: This is the process of breaking down glucose into pyruvate. Under aerobic conditions, pyruvate enters the Krebs cycle, but under anaerobic conditions, it can be converted into lactic acid through fermentation.

4. **Conclusion**: Since lactic acid is specifically produced during the fermentation of carbohydrates, the correct answer to the question is fermentation.

**Final Answer**: Lactic acid is produced in the process of fermentation.

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