The number of ATP obtained at the end of Krebs cycle

Options

A. 2 ATP
B. 4 ATP
C. 8 ATP
D. 38 ATP

Answer

To determine the number of ATP obtained at the end of 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 tricarboxylic acid (TCA) cycle, is a series of chemical reactions that occurs after glycolysis. It is essential for the aerobic respiration of glucose.

2. **Conversion of Pyruvic Acid**:
- After glycolysis, pyruvic acid is converted into acetyl CoA. This conversion does not produce ATP but generates NADH and releases carbon dioxide.

3. **Entry of Acetyl CoA into the Krebs Cycle**:
- Each molecule of glucose produces two molecules of pyruvic acid, which in turn produces two molecules of acetyl CoA. Therefore, two acetyl CoA molecules enter the Krebs cycle for each glucose molecule.

4. **ATP Production in the Krebs Cycle**:
- During the Krebs cycle, ATP is produced in one specific reaction. This occurs when alpha-ketoglutaric acid is converted into succinic acid, resulting in the formation of one ATP molecule.

5. **Total ATP from One Glucose Molecule**:
- Since each glucose molecule results in two acetyl CoA molecules entering the Krebs cycle, and each of these produces one ATP, the total ATP produced from one glucose molecule in the Krebs cycle is 2 ATP (1 ATP from each acetyl CoA).

6. **Conclusion**:
- Therefore, the total number of ATP obtained at the end of the Krebs cycle from one molecule of glucose is **2 ATP**.

### Final Answer:
The number of ATP obtained at the end of the Krebs cycle is **2 ATP**.

---