Formation of lactic acid from pyruvate requires

Options

A. Decarboxylation
B. Reduction
C. Oxidation
D. Hydration.

Answer

### Step-by-Step Solution:

1. **Understanding the Process**: The question asks about the conversion of pyruvate to lactic acid. This process occurs during anaerobic respiration, particularly in muscle cells when oxygen is scarce.

2. **Identifying the Reaction**: The conversion of pyruvate to lactic acid involves the addition of electrons and protons to pyruvate, which results in the formation of lactic acid.

3. **Analyzing the Options**:
- **Decarboxylation**: This process involves the removal of carbon dioxide (CO2). Since the conversion of pyruvate to lactic acid does not involve the release of CO2, this option is incorrect.
- **Hydration**: This involves the addition of water. The formation of lactic acid does not require the addition of water, so this option is also incorrect.
- **Oxidation**: In this process, a substance loses electrons. However, during the conversion of pyruvate to lactic acid, electrons are actually gained, indicating that oxidation is not occurring.
- **Reduction**: This process involves the gain of electrons. In the conversion of pyruvate to lactic acid, NADH donates electrons and protons to pyruvate, resulting in the formation of lactic acid. Therefore, this process is a reduction.

4. **Conclusion**: The correct answer is that the formation of lactic acid from pyruvate requires **reduction**.

### Final Answer:
The formation of lactic acid from pyruvate requires **reduction**.

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