Which is correct in photorespiration ?

Options

A. In mitochondria serine is converted into hydroxypyruvate
B. In mitchondria two glycine molecules unite to form serine
C. In mitochondria, glycolate is oxidised to form glyoxylate
D. In peroxisomes, three molecules of glycine unite to form serine.

Answer

To answer the question "Which is correct in photorespiration?", we will analyze the statements provided and determine their accuracy based on the process of photorespiration.

### Step-by-Step Solution:

1. **Understanding Photorespiration**:
- Photorespiration is a process that occurs in plants, particularly C3 plants, where the enzyme RuBisCO binds to oxygen instead of carbon dioxide. This leads to the formation of wasteful products and does not produce ATP or NADPH.

2. **Analyzing the Statements**:
- **Statement 1**: "In mitochondria, serine is converted into hydroxypyruvate."
- This statement is incorrect. In mitochondria, glycine is converted into serine, not the other way around.

- **Statement 2**: "In mitochondria, two glycine molecules unite to form serine."
- This statement is correct. During photorespiration, two molecules of glycine combine to form serine in the mitochondria.

- **Statement 3**: "In mitochondria, glycolate is oxidized to form glyoxylate."
- This statement is incorrect. Glycolate is oxidized to glyoxylate in the peroxisomes, not in the mitochondria.

- **Statement 4**: "In peroxisomes, three molecules of glycine unite to form serine."
- This statement is also incorrect. In peroxisomes, glycolate is converted to glyoxylate, not glycine to serine.

3. **Conclusion**:
- The only correct statement regarding photorespiration is **Statement 2**: "In mitochondria, two glycine molecules unite to form serine."

### Final Answer:
The correct statement in photorespiration is: **In mitochondria, two glycine molecules unite to form serine.**

---