The substrate in Krebs cycle which undergoes a reaction very similar to pyruvic acid in mitochondria is

Options

A. aconitate
B. succinic acid
C. alpha - ketoglutaric acid
D. fumaric acid

Answer

To solve the question regarding the substrate in the Krebs cycle that undergoes a reaction similar to pyruvic acid in mitochondria, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Pyruvic Acid in Mitochondria**:
- Pyruvic acid (or pyruvate) is the end product of glycolysis. It enters the mitochondria where it is converted into Acetyl-CoA through a process called decarboxylation. During this process, one molecule of CO2 is released, and NAD+ is reduced to NADH.

2. **Identifying the Krebs Cycle**:
- The Krebs cycle (also known as the citric acid cycle or TCA cycle) occurs in the mitochondrial matrix. It involves a series of reactions that produce energy through the oxidation of Acetyl-CoA.

3. **Finding a Similar Reaction in the Krebs Cycle**:
- In the Krebs cycle, after Acetyl-CoA enters, it combines with oxaloacetate to form citrate. The cycle then progresses through several intermediates.
- One of the key steps in the Krebs cycle is the conversion of isocitrate to alpha-ketoglutarate. This step involves the release of CO2 and the reduction of NAD+ to NADH, which is similar to the conversion of pyruvate to Acetyl-CoA.

4. **Identifying the Correct Substrate**:
- The question asks for the substrate in the Krebs cycle that undergoes a reaction similar to that of pyruvic acid. The substrate that fits this description is **alpha-ketoglutaric acid**, as it undergoes a decarboxylation reaction similar to that of pyruvate.

5. **Conclusion**:
- Therefore, the substrate in the Krebs cycle that undergoes a reaction very similar to pyruvic acid in mitochondria is **alpha-ketoglutaric acid**.

### Final Answer:
The substrate in the Krebs cycle which undergoes a reaction very similar to pyruvic acid in mitochondria is **alpha-ketoglutaric acid**.

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