Out of 38 ATP molecules per glucose, 30 ATP molecules are formed from `NADH//FADH_(2)` in

Options

A. Respiratory chain
B. Krebs cycle
C. Oxidative decarboxylation
D. EMP.

Answer

To solve the question regarding the formation of ATP molecules from NADH and FADH2 during cellular respiration, we can break down the process into clear steps:

### Step-by-Step Solution:

1. **Understanding Cellular Respiration**:
- Cellular respiration is the process by which glucose is broken down to produce ATP. It consists of several stages: glycolysis, the Krebs cycle, and oxidative phosphorylation (electron transport chain).

2. **Glycolysis**:
- Glycolysis occurs in the cytoplasm and converts one glucose molecule into two molecules of pyruvate.
- During glycolysis, 2 NADH molecules are produced, which can yield approximately 6 ATP (3 ATP per NADH).
- Additionally, 4 ATP are produced directly during glycolysis, but 2 ATP are consumed in the preparatory phase, resulting in a net gain of 8 ATP from glycolysis.

3. **Krebs Cycle**:
- Each pyruvate enters the Krebs cycle, which occurs in the mitochondria.
- For each pyruvate, the Krebs cycle produces:
- 4 NADH (which yield 12 ATP, as each NADH yields 3 ATP).
- 1 FADH2 (which yields 2 ATP).
- 1 GTP (equivalent to 1 ATP).
- Therefore, the total ATP yield per pyruvate is 15 ATP.
- Since one glucose molecule produces two pyruvate molecules, the total ATP yield from the Krebs cycle for one glucose molecule is 15 ATP x 2 = 30 ATP.

4. **Conclusion**:
- The question specifically asks where the 30 ATP molecules formed from NADH and FADH2 come from. The answer is the Krebs cycle.

### Final Answer:
The 30 ATP molecules are formed from NADH and FADH2 in the **Krebs cycle**.