The correct sequence of four carbon acids formed during Krebs cycle is

Options

A. oxalo - acetic acid - fumaric acid - malic acid - succinic acid
B. oxalo - acetic acid - malic acid - fumaric acid - succinic acid
C. succinic acid - malic acid - fumaric acid - oxalo - acetic acid
D. succinic acid - fumaric acid - malic acid -oxalo - acetic acid

Answer

To determine the correct sequence of four carbon acids formed during the Krebs cycle, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Krebs Cycle**: The Krebs cycle, also known as the citric acid cycle or TCA cycle, is a series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins.

2. **Starting Point**: The cycle begins with the combination of Acetyl-CoA and Oxaloacetate (also known as oxaloacetic acid) to form Citrate (Citric Acid).

3. **Formation of Intermediates**:
- Citrate is then converted to Isocitrate.
- Isocitrate undergoes decarboxylation to form Alpha-Ketoglutarate.
- Alpha-Ketoglutarate is further converted to Succinyl-CoA.
- Succinyl-CoA is then converted to Succinate.
- Succinate is converted to Fumarate.
- Fumarate is converted to Malate.
- Finally, Malate is converted back to Oxaloacetate, completing the cycle.

4. **Identifying the Four Carbon Acids**:
- The four carbon acids in the sequence are:
- Succinic Acid (Succinate)
- Fumaric Acid (Fumarate)
- Malic Acid (Malate)
- Oxaloacetic Acid (Oxaloacetate)

5. **Correct Sequence**: Based on the order of formation:
- The correct sequence of four carbon acids formed during the Krebs cycle is:
- Succinic Acid → Fumaric Acid → Malic Acid → Oxaloacetic Acid.

6. **Conclusion**: Therefore, the correct option from the given choices is the fourth option: "Succinic Acid, Fumaric Acid, Malic Acid, Oxaloacetic Acid."