Identify the reason for photorespiration not occurring in `C_4` plant

Options

A. `O_2` is not released in `C_4` plant during photosynthesis
B. intracellular concentration of `CO_2` is high in bundle sheath
C. the intracellular concentration of `CO_2` is low in bundle sheath cells
D. the intracellular concentration of `CO_2` is high in bundle sheath and mesophyll cells

Answer

To identify the reason for photorespiration not occurring in C4 plants, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Photorespiration**:
- Photorespiration is a process where the enzyme Rubisco binds with oxygen instead of carbon dioxide, leading to the production of phosphoglycolate instead of 3-phosphoglycerate. This process is wasteful as it does not produce sugar or ATP.

**Hint**: Photorespiration occurs when Rubisco binds with oxygen instead of carbon dioxide.

2. **Role of Rubisco**:
- Rubisco (Ribulose-1,5-bisphosphate carboxylase/oxygenase) can bind to both CO2 and O2. The balance of these gases in the environment affects which substrate Rubisco will bind to.

**Hint**: Rubisco's function depends on the concentration of CO2 and O2.

3. **C4 Plant Mechanism**:
- C4 plants, such as maize, have a specialized mechanism that increases the concentration of CO2 at the site of Rubisco. This is achieved through a two-step process involving mesophyll and bundle sheath cells.

**Hint**: C4 plants have a unique pathway that enhances CO2 concentration.

4. **Bundle Sheath Cells**:
- In C4 plants, CO2 is initially fixed in mesophyll cells and then transported to bundle sheath cells where it is released. This ensures that the concentration of CO2 remains high around Rubisco, preventing it from binding with O2.

**Hint**: High CO2 concentration in bundle sheath cells is crucial for preventing photorespiration.

5. **Conclusion**:
- The reason photorespiration does not occur in C4 plants is that the intracellular concentration of CO2 is high in bundle sheath cells, ensuring that Rubisco predominantly binds with CO2 rather than O2.

**Final Answer**: The correct option is that the intracellular concentration of CO2 is high in bundle sheath cells.

### Summary:
- Photorespiration is avoided in C4 plants due to the high concentration of CO2 in bundle sheath cells, which ensures that Rubisco binds with CO2 instead of O2.