Krebs cycle is

Options

A. Oxidation of glucose to alcohol and water
B. Oxidation of acetyl CoA to carbon dioxide and water involving electron transport
C. Complete oxidation of acetyl CoA without electron transport
D. Complete reduction of acetyl CoA to carbon doxide and water.

Answer

**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 biochemical reactions that occur in the mitochondria of cells. It is a crucial part of aerobic respiration.

2. **Starting Material**: The cycle begins with acetyl-CoA, which is derived from the breakdown of carbohydrates, fats, and proteins. Acetyl-CoA is formed from pyruvate through oxidative decarboxylation.

3. **Process of the Krebs Cycle**: During the Krebs cycle, acetyl-CoA is oxidized. This oxidation process leads to the release of energy, which is captured in the form of reduced coenzymes NADH and FADH2, as well as GTP (which can be converted to ATP).

4. **Products of the Krebs Cycle**: The main products of the Krebs cycle include carbon dioxide (CO2), reduced coenzymes (NADH and FADH2), and GTP. The carbon dioxide is released as a waste product.

5. **Electron Transport Chain**: After the Krebs cycle, the reduced coenzymes (NADH and FADH2) enter the electron transport chain, where further oxidation occurs, leading to the production of ATP.

6. **Evaluating the Options**:
- **Option A**: "Oxidation of glucose to alcohol and water" - This describes fermentation, not the Krebs cycle, which is incorrect.
- **Option B**: "Oxidation of acetyl-CoA to carbon dioxide and water involving electron transport" - This is incorrect because the electron transport chain is a separate process following the Krebs cycle.
- **Option C**: "Complete oxidation of acetyl-CoA without electron transport" - This is correct as the Krebs cycle involves the oxidation of acetyl-CoA without the involvement of the electron transport chain.
- **Option D**: "Complete reduction of acetyl-CoA to carbon dioxide and water" - This is incorrect because the Krebs cycle involves oxidation, not reduction.

7. **Conclusion**: The correct answer is **Option C**: "Complete oxidation of acetyl-CoA without electron transport."

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