In anaerobic respiration, acetaldehyde is reduced to form alcohol by utilising `NADH_(2)` obtained from

Options

A. Glycolysis
B. Terminal oxidation
C. Krebs cycle
D. Acetylation.

Answer

To solve the question regarding anaerobic respiration and the reduction of acetaldehyde to form alcohol, we can break down the process step-by-step:

### Step-by-Step Solution:

1. **Understanding Anaerobic Respiration**:
- Anaerobic respiration occurs in the absence of oxygen and involves the conversion of glucose to energy through fermentation pathways.

2. **Glycolysis**:
- The process begins with glycolysis, where one molecule of glucose (a six-carbon sugar) is broken down into two molecules of pyruvate (three-carbon compounds).
- During glycolysis, NAD+ is reduced to NADH, which serves as a reducing agent in subsequent reactions.

3. **Formation of Acetaldehyde**:
- In anaerobic conditions, the pyruvate produced from glycolysis is converted into acetaldehyde. This conversion involves the release of one molecule of carbon dioxide (decarboxylation).

4. **Reduction of Acetaldehyde to Ethanol**:
- Acetaldehyde is then reduced to ethanol (alcohol). This reduction requires a reducing agent, which in this case is NADH.
- The NADH used in this step is derived from the glycolysis process.

5. **Conclusion**:
- Therefore, in anaerobic respiration, acetaldehyde is reduced to form alcohol (ethanol) by utilizing NADH obtained from glycolysis.

### Final Answer:
In anaerobic respiration, acetaldehyde is reduced to form alcohol by utilizing NADH obtained from **glycolysis**.

---