Mitochondria are sites of

Options

A. Calvin cycle
B. Krebs cycle
C. Hill reaction
D. Glycolysis

Answer

**Step-by-Step Solution:**

1. **Understanding Mitochondria**: Mitochondria are known as the powerhouse of the cell because they are the primary site for ATP (adenosine triphosphate) production through cellular respiration.

2. **Evaluating the Options**:
- **Calvin Cycle**: This is a part of photosynthesis that occurs in the chloroplasts, specifically in the stroma. Since mitochondria are not involved in photosynthesis, this option is incorrect.
- **Krebs Cycle**: Also known as the citric acid cycle, this is a key metabolic pathway that takes place in the mitochondria. It is involved in aerobic respiration and is responsible for the oxidation of acetyl-CoA to carbon dioxide and energy. Therefore, this option is correct.
- **Hill Reaction**: This is part of the light-dependent reactions of photosynthesis, which occur in the chloroplasts. Since it does not take place in mitochondria, this option is incorrect.
- **Glycolysis**: This is the initial stage of glucose metabolism that occurs in the cytoplasm, not in the mitochondria. Therefore, this option is also incorrect.

3. **Conclusion**: Based on the evaluations, the only correct answer is the Krebs cycle, which occurs in the mitochondria.

**Final Answer**: Mitochondria are sites of the Krebs cycle.

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