The first compound of TCA cycle is

Options

A. Oxalo succini acid
B. Oxalo acetic acid
C. Citric acid
D. Cis aconitic acid

Answer

To solve the question "The first compound of TCA cycle is," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the TCA Cycle**: The TCA cycle, also known as the Krebs cycle or citric acid cycle, is a crucial metabolic pathway that plays a significant role in cellular respiration.

2. **Identify the First Compound**: The first compound formed in the TCA cycle is a stable product that contains three carboxylic acid groups, which is why it is referred to as the tricarboxylic acid cycle.

3. **Know the Reactants**: The first stable compound is formed from the condensation of two molecules: one molecule of acetyl coenzyme A (acetyl CoA) and one molecule of oxaloacetic acid.

4. **Determine the Product**: The reaction between acetyl CoA and oxaloacetic acid results in the formation of citric acid, also known as citrate. This compound is the first stable product of the TCA cycle.

5. **Conclude the Answer**: Therefore, the first compound of the TCA cycle is citric acid (or citrate).

### Final Answer:
The first compound of the TCA cycle is citric acid.