Oxidation of one molecule of glucose in aerobic respiration produces

Options

A. 2 ATP
B. 30 ATP
C. 36 ATP
D. 38 ATP

Answer

To determine the total ATP produced from the oxidation of one molecule of glucose during aerobic respiration, we can break down the process into its three main stages: glycolysis, the Krebs cycle, and oxidative decarboxylation. Here’s a step-by-step solution:

### Step 1: Glycolysis
- **Process**: Glycolysis occurs in the cytoplasm and breaks down one molecule of glucose into two molecules of pyruvate.
- **ATP Production**: During glycolysis, 2 ATP molecules are produced directly.
- **NADH Production**: Additionally, 2 NADH molecules are produced.
- **ATP from NADH**: Each NADH can generate approximately 3 ATP when oxidized in the electron transport chain. Therefore, 2 NADH will yield about 6 ATP.

**Total from Glycolysis**:
- ATP = 2 (direct) + 6 (from NADH) = 8 ATP

### Step 2: Krebs Cycle (Citric Acid Cycle)
- **Process**: The Krebs cycle occurs in the mitochondria and processes the pyruvate produced from glycolysis.
- **NADH and FADH2 Production**: In one turn of the Krebs cycle, 6 NADH, 2 FADH2, and 2 GTP (which can be converted to ATP) are produced.
- **ATP from NADH**: The 6 NADH will yield approximately 18 ATP (6 NADH x 3 ATP each).
- **ATP from FADH2**: The 2 FADH2 will yield approximately 4 ATP (2 FADH2 x 2 ATP each).
- **GTP to ATP**: The 2 GTP can be considered as 2 ATP.

**Total from Krebs Cycle**:
- ATP = 18 (from NADH) + 4 (from FADH2) + 2 (from GTP) = 24 ATP

### Step 3: Oxidative Decarboxylation
- **Process**: This step occurs before the Krebs cycle and involves the conversion of pyruvate to acetyl-CoA.
- **NADH Production**: During this process, 2 NADH are produced.
- **ATP from NADH**: These 2 NADH will yield approximately 6 ATP.

**Total from Oxidative Decarboxylation**:
- ATP = 6 ATP

### Final Calculation
Now, we can sum up the ATP produced from all three stages:
- From Glycolysis: 8 ATP
- From Krebs Cycle: 24 ATP
- From Oxidative Decarboxylation: 6 ATP

**Total ATP Produced**:
- Total ATP = 8 + 24 + 6 = 38 ATP

### Conclusion
The oxidation of one molecule of glucose in aerobic respiration produces **38 ATP**.

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