During photorespiration , phosphorylation as well as oxdiation occurs in

Options

A. Centrosame
B. Peroxisome
C. mitochondria
D. Chloroplast

Answer

**Step-by-Step Solution:**

1. **Understanding Photorespiration**:
- Photorespiration is a process that occurs in plants, particularly C3 plants, when the concentration of carbon dioxide (CO2) is low and the concentration of oxygen (O2) is high.

2. **Characteristics of Photorespiration**:
- It is also known as oxidative photosynthesis or C2 photosynthesis.
- This process consumes more ATP and NADPH, which are high-energy molecules produced during the light reactions of photosynthesis.
- It is often referred to as a "waste process" because it prevents plants from utilizing their ATP and NADPH for carbohydrate synthesis.

3. **Involvement of Organelles**:
- Photorespiration involves three main organelles:
- **Chloroplasts**: Where the initial reactions occur.
- **Peroxisomes**: Involved in the breakdown of byproducts.
- **Mitochondria**: Plays a role in the energy transformation processes.

4. **Role of Rubisco**:
- The enzyme Rubisco (ribulose bisphosphate carboxylase/oxygenase) is crucial in this process.
- When CO2 levels are low, Rubisco binds to O2 instead of CO2, leading to the oxidation of organic molecules.

5. **Processes Occurring**:
- During photorespiration, both phosphorylation (the addition of a phosphate group to a molecule) and oxidation (the loss of electrons from a molecule) occur simultaneously.
- The phosphorylation process occurs in the chloroplasts, where ATP is generated, while oxidation occurs due to the action of Rubisco on O2.

6. **Conclusion**:
- Therefore, during photorespiration, phosphorylation as well as oxidation occurs primarily in the **chloroplasts**.

**Final Answer**: During photorespiration, phosphorylation as well as oxidation occurs in the chloroplasts.

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