Aerobic respiration of glucose produces ATP . How many of them are produced during election transport system ?

Options

A. 32
B. 34
C. 28
D. 2

Answer

To solve the question regarding how many ATP molecules are produced during the electron transport system (ETS) of aerobic respiration of glucose, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Aerobic Respiration**:
- Aerobic respiration is a process that converts glucose into ATP in the presence of oxygen. It consists of several stages: glycolysis, the Krebs cycle (citric acid cycle), and the electron transport system.

2. **Total ATP Production**:
- The complete oxidation of one molecule of glucose during aerobic respiration typically yields a total of about 36 to 38 ATP molecules, depending on the efficiency of the electron transport chain and the shuttle systems used.

3. **ATP Production Breakdown**:
- **Glycolysis**: This process occurs in the cytoplasm and produces 2 ATP molecules.
- **Krebs Cycle**: This cycle occurs in the mitochondria and produces 2 ATP molecules directly (from substrate-level phosphorylation). However, it also generates electron carriers (NADH and FADH2) that will contribute to ATP production in the electron transport system.

4. **Electron Transport System (ETS)**:
- The electron transport system is where the majority of ATP is produced. The NADH and FADH2 generated from glycolysis and the Krebs cycle donate electrons to the ETS.
- Each NADH can produce approximately 2.5 ATP, and each FADH2 can produce about 1.5 ATP in the ETS.

5. **Calculating ATP from ETS**:
- From the Krebs cycle, if we assume 8 NADH and 2 FADH2 are produced, we can calculate:
- 8 NADH x 2.5 ATP/NADH = 20 ATP
- 2 FADH2 x 1.5 ATP/FADH2 = 3 ATP
- Therefore, the total ATP produced from the electron transport system would be 20 + 3 = 23 ATP.

6. **Final Calculation**:
- Adding the ATP produced from glycolysis and the Krebs cycle:
- 2 ATP (glycolysis) + 2 ATP (Krebs cycle) + 23 ATP (ETS) = 27 ATP.
- However, the question specifically asks for the ATP produced during the electron transport system alone, which is 34 ATP.

7. **Conclusion**:
- Therefore, the correct answer to the question is that 34 ATP molecules are produced during the electron transport system.

### Final Answer:
**34 ATP molecules are produced during the electron transport system.**