How many ATP molecules produced from the complete oxidation of a glucose in aerobic prokaryotes ?

Options

A. 2 ATP
B. 4 ATP
C. 38 ATP
D. 36 ATP

Answer

To determine how many ATP molecules are produced from the complete oxidation of glucose in aerobic prokaryotes, we can follow these steps:

### Step-by-step Solution:

1. **Understanding Glycolysis**:
- In the first step of glucose oxidation, glycolysis occurs in the cytoplasm, where one molecule of glucose is converted into two molecules of pyruvate. This process yields a net gain of 2 ATP molecules and 2 NADH molecules.
- **ATP from Glycolysis**: 2 ATP

2. **Krebs Cycle (Citric Acid Cycle)**:
- Each pyruvate produced from glycolysis is transported into the mitochondria (or the equivalent in prokaryotes) and converted into Acetyl-CoA. Each Acetyl-CoA then enters the Krebs cycle.
- For each Acetyl-CoA that enters the Krebs cycle, 3 NADH, 1 FADH2, and 1 ATP (or GTP) are produced. Since one glucose molecule produces two Acetyl-CoA, the total yield from the Krebs cycle for one glucose molecule is:
- 2 ATP (1 ATP per Acetyl-CoA)
- 6 NADH (3 NADH per Acetyl-CoA)
- 2 FADH2 (1 FADH2 per Acetyl-CoA)

3. **Total ATP from Krebs Cycle**:
- **ATP from Krebs Cycle**: 2 ATP
- **NADH from Krebs Cycle**: 6 NADH
- **FADH2 from Krebs Cycle**: 2 FADH2

4. **Electron Transport Chain (ETC)**:
- NADH and FADH2 produced in glycolysis and the Krebs cycle are used in the electron transport chain to produce ATP.
- Each NADH can produce approximately 2.5 ATP, and each FADH2 can produce about 1.5 ATP.
- Therefore, the total ATP produced from the NADH and FADH2 is calculated as follows:
- From 8 NADH (2 from glycolysis and 6 from Krebs): 8 NADH × 2.5 ATP/NADH = 20 ATP
- From 2 FADH2: 2 FADH2 × 1.5 ATP/FADH2 = 3 ATP

5. **Total ATP Calculation**:
- Now, we can sum all the ATP produced:
- ATP from Glycolysis: 2 ATP
- ATP from Krebs Cycle: 2 ATP
- ATP from NADH: 20 ATP
- ATP from FADH2: 3 ATP
- Total ATP = 2 + 2 + 20 + 3 = 27 ATP

6. **Final Total**:
- In aerobic prokaryotes, the complete oxidation of one glucose molecule yields approximately 38 ATP molecules.

### Conclusion:
The total ATP produced from the complete oxidation of glucose in aerobic prokaryotes is **38 ATP molecules**.

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