The substrate of photorespiration is formed in

Options

A. Peroxisome
B. Mitochondrion
C. Chloroplast
D. Glyoxysome

Answer

**Step-by-Step Solution:**

1. **Understanding Photorespiration**: Photorespiration is a process that occurs in plants where the enzyme Rubisco reacts with oxygen instead of carbon dioxide, leading to the production of a compound that is not useful for the plant's energy needs.

2. **Role of Rubisco**: In the Calvin cycle, Rubisco typically catalyzes the reaction between carbon dioxide and ribulose bisphosphate (RuBP). However, during photorespiration, it reacts with oxygen, resulting in the formation of phosphoglycolate.

3. **Formation of Glycolate**: The phosphoglycolate produced in photorespiration is then rapidly converted through a series of reactions into glycolate. Glycolate is the first substrate formed during the photorespiration process.

4. **Location of Glycolate Formation**: Glycolate is specifically formed in the chloroplasts of plant cells. This is a crucial point because it identifies where the substrate of photorespiration originates.

5. **Subsequent Metabolism**: After glycolate is formed in the chloroplast, it is then transported to other organelles, such as peroxisomes and mitochondria, for further metabolism. However, the question specifically asks for the site of substrate formation.

6. **Conclusion**: Based on the above points, the substrate of photorespiration, glycolate, is formed in the chloroplasts.

**Final Answer**: The substrate of photorespiration is formed in the chloroplast.

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