One molecule of pyruvic acid produces _____ molecules of `CO_(2)` in mitochondrion

Options

A. 3
B. 2
C. 4
D. 6

Answer

**Step-by-Step Text Solution:**

1. **Understanding Pyruvic Acid**: Pyruvic acid is a three-carbon compound that is produced during glycolysis. It is the end product of glucose metabolism in the cytoplasm.

2. **Conversion to Acetyl CoA**: Before entering the Krebs cycle (also known as the TCA cycle or citric acid cycle), pyruvic acid is converted into acetyl CoA. This process involves the removal of one carbon atom from pyruvic acid, which is released as carbon dioxide (CO₂). Thus, one molecule of CO₂ is produced during this conversion.

3. **Entering the Krebs Cycle**: The acetyl CoA, which is a two-carbon compound, then enters the Krebs cycle. The Krebs cycle involves a series of reactions that further oxidize the acetyl CoA to produce energy.

4. **Carbon Dioxide Production in the Krebs Cycle**: During the Krebs cycle, two additional molecules of CO₂ are released. Specifically, this occurs during the conversion of isocitrate to alpha-ketoglutarate and from alpha-ketoglutarate to succinyl CoA.

5. **Total CO₂ Production**: Therefore, from one molecule of pyruvic acid, we have:
- 1 CO₂ from the conversion to acetyl CoA
- 2 CO₂ from the Krebs cycle
- Total: 1 + 2 = 3 CO₂ molecules produced.

6. **Final Answer**: One molecule of pyruvic acid produces **3 molecules of CO₂** in the mitochondrion.

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