Source of hydrogen for the reduction of acetaldehyde into ethyl alcohol in anaerobic respiration is

Options

A. `FADH_(2)`
B. `NADPH_(2)`
C. `NADH_(2)`
D. TPP

Answer

To answer the question regarding the source of hydrogen for the reduction of acetaldehyde into ethyl alcohol in anaerobic respiration, we can break down the process step by step:

### Step-by-Step Solution:

1. **Understanding Anaerobic Respiration**:
- In anaerobic respiration, organisms such as yeast convert glucose into energy without the presence of oxygen. This process leads to the production of ethanol (ethyl alcohol) and carbon dioxide.

2. **Conversion of Pyruvate**:
- During anaerobic respiration in yeast, glucose is first broken down into pyruvate through glycolysis.
- Pyruvate then undergoes decarboxylation, where a carbon dioxide (CO2) molecule is removed, resulting in the formation of acetaldehyde.

3. **Role of Enzymes**:
- The enzyme responsible for the conversion of pyruvate to acetaldehyde is called **pyruvate decarboxylase**. This enzyme catalyzes the removal of CO2 from pyruvate.

4. **Reduction of Acetaldehyde**:
- The next step involves the reduction of acetaldehyde to ethanol. This reaction is catalyzed by the enzyme **alcohol dehydrogenase**.
- During this reduction, hydrogen is transferred from NADH (the reduced form of NAD+) to acetaldehyde.

5. **Source of Hydrogen**:
- The hydrogen that is used in this reduction comes from NADH. In the process, NADH is oxidized back to NAD+.

6. **Final Products**:
- The end products of this reaction are ethanol (ethyl alcohol) and NAD+.

### Conclusion:
The source of hydrogen for the reduction of acetaldehyde into ethyl alcohol in anaerobic respiration is **NADH**.

---