Choose the correct statement w. r.t. RuBisCO

Options

A. Binding of O_2 and CO_2 at active site is not competitive
B. Can bind to O_2 and CO_2 with equal affinity
C. Participate in photo respiration
D. Absent in bundle sheath cells

Answer

To solve the question regarding RuBisCO, we will evaluate each of the provided statements to determine which one is correct.

### Step-by-Step Solution:

1. **Understanding RuBisCO**:
- RuBisCO stands for ribulose 1,5-bisphosphate carboxylase/oxygenase. It is a crucial enzyme in the process of carbon fixation during photosynthesis.

2. **Evaluating the Statements**:
- **Statement 1**: "Binding of oxygen and carbon dioxide at active site is not competitive."
- This statement is incorrect. RuBisCO has a competitive binding mechanism for both oxygen and carbon dioxide at its active site. When the concentrations of both gases are comparable, they compete for binding.

- **Statement 2**: "Rubisco can bind to oxygen and carbon dioxide with equal affinity."
- This statement is also incorrect. RuBisCO has a higher affinity for carbon dioxide compared to oxygen, meaning it prefers to bind carbon dioxide.

- **Statement 3**: "It participates in photorespiration."
- This statement is correct. RuBisCO can catalyze the reaction of oxygen with ribulose bisphosphate (RuBP), leading to photorespiration, especially under conditions of high oxygen concentration.

- **Statement 4**: "It is absent in bundle sheath cells."
- This statement is incorrect. In C4 plants, RuBisCO is present in the bundle sheath cells, where it plays a role in the Calvin cycle.

3. **Conclusion**:
- After evaluating all the statements, the only correct statement is **Statement 3**, which states that RuBisCO participates in photorespiration.

### Final Answer:
The correct statement with respect to RuBisCO is: **It participates in photorespiration.**