How many decarboxylation occur and mitochondria during oxidation of glucose?

Options

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

Answer

### Step-by-Step Solution:

1. **Understanding the Process**: The question asks about the number of decarboxylation reactions that occur in the mitochondria during the oxidation of glucose. Decarboxylation is the process of removing a carboxyl group from a molecule, releasing carbon dioxide (CO2).

2. **Glycolysis Overview**: Initially, glucose undergoes glycolysis in the cytoplasm, producing pyruvate. Pyruvate then enters the mitochondria where it is converted into acetyl coenzyme A (acetyl CoA). During this conversion, one molecule of CO2 is released, which counts as the first decarboxylation.

3. **Krebs Cycle Introduction**: Acetyl CoA enters the Krebs cycle (also known as the citric acid cycle or TCA cycle). The Krebs cycle is a series of reactions that further oxidizes the acetyl group.

4. **First Decarboxylation in Krebs Cycle**: The first decarboxylation in the Krebs cycle occurs when isocitrate is converted into alpha-ketoglutarate. During this reaction, one molecule of CO2 is released.

5. **Second Decarboxylation in Krebs Cycle**: The second decarboxylation occurs when alpha-ketoglutarate is converted into succinyl CoA. Again, another molecule of CO2 is released during this process.

6. **Summary of Decarboxylation Events**:
- First decarboxylation: Pyruvate to Acetyl CoA (1 CO2 released).
- Second decarboxylation: Isocitrate to Alpha-ketoglutarate (1 CO2 released).
- Third decarboxylation: Alpha-ketoglutarate to Succinyl CoA (1 CO2 released).

7. **Total Count**: Adding these together, we find that there are a total of 3 decarboxylation events during the complete oxidation of one molecule of glucose in the mitochondria.

### Final Answer:
**There are 3 decarboxylation reactions that occur in the mitochondria during the oxidation of glucose.**

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