In photorespiration, RuBP carboxylase combines with oxygen to yield

Options

A. Two molecules of phosphoglycerate
B. Two molecules of phosphoglycolate
C. One molecule of phosphoglycerate and one molecule of phosphoglycolate
D. Two molecule of glucose

Answer

To answer the question about what products are formed when RuBP carboxylase combines with oxygen during photorespiration, we can break down the process step by step:

### Step-by-Step Solution:

1. **Understanding the Enzyme and Substrate**:
- RuBP carboxylase, commonly known as rubisco, is the enzyme responsible for catalyzing the first step of carbon fixation in photosynthesis. It typically combines ribulose bisphosphate (RuBP) with carbon dioxide (CO₂).

2. **Normal Photosynthesis vs. Photorespiration**:
- In normal photosynthesis, rubisco combines RuBP with CO₂ to produce two molecules of 3-phosphoglycerate (3-PGA).
- In photorespiration, however, rubisco reacts RuBP with oxygen (O₂) instead of CO₂.

3. **Products of Photorespiration**:
- When RuBP combines with O₂ in the process of photorespiration, it yields one molecule of 3-phosphoglycerate (3-PGA) and one molecule of phosphoglycolate.
- Therefore, the products of this reaction are:
- 1 molecule of 3-phosphoglycerate (3-PGA)
- 1 molecule of phosphoglycolate

4. **Significance of Photorespiration**:
- Photorespiration is considered a wasteful process because it reduces the efficiency of photosynthesis by decreasing the fixation of carbon dioxide, which is essential for producing glucose and other carbohydrates.

### Final Answer:
In photorespiration, RuBP carboxylase combines with oxygen to yield:
- 1 molecule of 3-phosphoglycerate (3-PGA)
- 1 molecule of phosphoglycolate

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