The reactions which change lactic acid into glycogen

Options

A. Calvin cycle
B. Cori cycle
C. Krebs cycle
D. Glycolysis

Answer

**Step-by-Step Solution:**

1. **Understanding the Context**: The question asks about the reactions that convert lactic acid into glycogen. This process is crucial during strenuous exercise when the body relies on anaerobic respiration, leading to lactic acid accumulation.

2. **Identifying the Relevant Cycle**: The correct cycle that facilitates the conversion of lactic acid into glycogen is known as the **Cori Cycle**. This cycle is essential for recycling lactic acid produced in muscles back into glucose in the liver.

3. **Explaining the Cori Cycle**: During intense physical activity, when oxygen levels are low, glucose is metabolized anaerobically, resulting in the production of lactic acid. This lactic acid is transported to the liver, where it undergoes a series of reactions to be converted back into glucose, which can then be stored as glycogen.

4. **Eliminating Incorrect Options**:
- **Calvin Cycle**: This cycle is involved in photosynthesis in plants, converting carbon dioxide into glucose, and is not related to lactic acid metabolism.
- **Krebs Cycle**: Also known as the citric acid cycle, it is involved in aerobic respiration and energy production but does not convert lactic acid to glycogen.
- **Glycolysis**: This process breaks down glucose into pyruvate and is not directly involved in converting lactic acid to glycogen.

5. **Conclusion**: The correct answer to the question is the **Cori Cycle**, as it specifically describes the reactions that convert lactic acid back into glycogen in the liver.

**Final Answer**: The reactions which change lactic acid into glycogen occur through the **Cori Cycle**.

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