In photorespiration , the first stable product is
(a) oxalo acetate.
(b) phosphoglycerate.
(c) phosphoglycerate and phosphoglycolate.
(d) None of these

Options

A. oxalo acetate.
B. phosphoglycerate.
C. phosphoglycerate and phosphoglycolate.
D. None of these

Answer

To solve the question regarding the first stable product of photorespiration, let's break down the information step by step.

### Step-by-Step Solution:

1. **Understanding Photorespiration**:
- Photorespiration is a process that occurs in plants, particularly in C3 plants, where the enzyme ribulose bisphosphate carboxylase/oxygenase (Rubisco) interacts with oxygen instead of carbon dioxide.
- This process is often considered wasteful because it leads to the consumption of ATP and does not result in the production of glucose.

2. **Identifying the Products**:
- When Rubisco acts as an oxygenase, it catalyzes the reaction between ribulose bisphosphate (RuBP) and oxygen, leading to the formation of two products:
- **3-Phosphoglycerate (3-PGA)**: This is a three-carbon compound that enters the Calvin cycle.
- **Phosphoglycolate**: This is another product formed during photorespiration.

3. **Analyzing the Options**:
- (a) **Oxaloacetate**: This is primarily associated with C4 plants and is not a product of photorespiration.
- (b) **Phosphoglycerate**: This is indeed one of the products formed during photorespiration.
- (c) **Phosphoglycerate and Phosphoglycolate**: Both of these are products formed during photorespiration.
- (d) **None of these**: This option does not apply since we have identified products.

4. **Conclusion**:
- The first stable product of photorespiration includes both phosphoglycerate and phosphoglycolate. Therefore, the correct answer is:
- **(c) Phosphoglycerate and Phosphoglycolate**.

### Final Answer:
**(c) Phosphoglycerate and Phosphoglycolate.**

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