How many molecules of carbon dioxide will be produced if two molecules of Acetyl CoA is Completely oxidized in aerobic respiration ?

Options

A. One
B. Two
C. Three
D. Four

Answer

To determine how many molecules of carbon dioxide (CO2) are produced when two molecules of Acetyl CoA are completely oxidized in aerobic respiration, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Role of Acetyl CoA**: Acetyl CoA is a key molecule that enters the Krebs cycle (also known as the citric acid cycle or TCA cycle) during aerobic respiration.

2. **Krebs Cycle Overview**: In one complete turn of the Krebs cycle, one molecule of Acetyl CoA produces:
- 2 molecules of CO2
- 3 molecules of NADH
- 1 molecule of FADH2
- 1 molecule of ATP (or GTP)

3. **Calculate CO2 Production for One Acetyl CoA**: Since one molecule of Acetyl CoA results in the production of 2 molecules of CO2, we can summarize:
- 1 Acetyl CoA → 2 CO2

4. **Calculate CO2 Production for Two Acetyl CoA**: If we have 2 molecules of Acetyl CoA, we can multiply the CO2 produced by one Acetyl CoA by 2:
- 2 Acetyl CoA → 2 × 2 CO2 = 4 CO2

5. **Final Result**: Therefore, when two molecules of Acetyl CoA are completely oxidized, a total of 4 molecules of CO2 are produced.

### Conclusion:
The total number of carbon dioxide molecules produced from the complete oxidation of two molecules of Acetyl CoA in aerobic respiration is **4 CO2**.

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