Krebs' cycle starts with reaction between

Options

A. OAA+Acetyl CoA
B. OAA+Pyruvic acid
C. Acetyl CoA+Citric acid
D. OAA+Citric acid

Answer

**Step-by-Step Solution:**

1. **Understanding the Krebs Cycle**: The Krebs cycle, also known as the citric acid cycle, is a crucial part of cellular respiration that occurs in aerobic organisms. It involves a series of chemical reactions that generate energy.

2. **Identifying the Starting Reaction**: The question asks about the starting reaction of the Krebs cycle. The cycle begins with the formation of a 6-carbon compound.

3. **Reactants Involved**: The 6-carbon compound is formed from the reaction between oxaloacetic acid and acetyl coenzyme A.

4. **Formation of Citric Acid**: When oxaloacetic acid (a 4-carbon compound) reacts with acetyl coenzyme A (a 2-carbon compound), they combine to form citric acid (also known as citrate), which is a 6-carbon compound.

5. **Catalysis**: This reaction is catalyzed by the enzyme citrate synthase, and during this process, coenzyme A is released.

6. **Conclusion**: Therefore, the correct answer to the question "Krebs' cycle starts with the reaction between" is **oxaloacetic acid and acetyl coenzyme A**.

**Final Answer**: The Krebs cycle starts with the reaction between oxaloacetic acid and acetyl coenzyme A.

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