During respiration, 38 ATP molecule per glucose molecule are produced in respiration chain, 22 molecules of these 38 ATP molecules are produced from `NADH_(2)//FADH_(2)` produced during

Options

A. Embden-Meyerhof pathway
B. Oxidative phosphorylation
C. Kreb's cycle
D. Respiratory chain itself

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question states that during respiration, a total of 38 ATP molecules are produced per glucose molecule, and specifically asks about the 22 ATP molecules that are generated from NADH and FADH2.

2. **Identifying the Pathways**: We need to identify which metabolic pathway produces NADH and FADH2 that contribute to the ATP production. The options provided are:
- Option 1: Embden-Meyerhof pathway (Glycolysis)
- Option 2: Oxidative Phosphorylation
- Option 3: Krebs Cycle
- Option 4: Respiratory Chain

3. **Analyzing Each Option**:
- **Option 1 (Embden-Meyerhof pathway)**: This is glycolysis, which produces a net gain of 2 ATP molecules and 2 NADH molecules. However, it does not account for the 22 ATP molecules.
- **Option 2 (Oxidative Phosphorylation)**: This process is where the majority of ATP is produced, specifically from the NADH and FADH2 generated in earlier stages of respiration. This is the correct pathway that leads to the production of 22 ATP molecules.
- **Option 3 (Krebs Cycle)**: This cycle produces 2 ATP molecules directly, along with additional NADH and FADH2, but does not account for the 22 ATP molecules on its own.
- **Option 4 (Respiratory Chain)**: This is another term for oxidative phosphorylation, but it does not directly produce NADH or FADH2.

4. **Conclusion**: The correct answer is **Option 2: Oxidative Phosphorylation**, as it is responsible for producing the 22 ATP molecules from the NADH and FADH2 generated in glycolysis and the Krebs cycle.

**Final Answer**: The 22 ATP molecules are produced from NADH and FADH2 during **Oxidative Phosphorylation**.

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