PEP carboxylase is associated with

Options

A. CAM plants
B. `C_3` plants
C. `C_4` plants
D. (1) & (3)

Answer

To solve the question regarding the association of PEP carboxylase, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Role of PEP Carboxylase**:
- PEP carboxylase is an enzyme that catalyzes the reaction where carbon dioxide (CO2) is fixed to a three-carbon compound called phosphoenolpyruvate (PEP) to form a four-carbon compound.

2. **Identify the Types of Plants**:
- The question provides four options: CAM plants, C3 plants, C4 plants, and both CAM and C4 plants.

3. **Analyze CAM Plants**:
- CAM (Crassulacean Acid Metabolism) plants utilize PEP carboxylase for carbon fixation during the night. They convert CO2 into malic acid, which is stored until daylight when photosynthesis occurs.

4. **Analyze C4 Plants**:
- C4 plants also use PEP carboxylase for carbon fixation. They convert CO2 into a four-carbon compound in mesophyll cells, which is then transported to bundle sheath cells for the Calvin cycle.

5. **Analyze C3 Plants**:
- C3 plants do not primarily use PEP carboxylase. Instead, they rely on the enzyme RuBisCO for carbon fixation in the Calvin cycle. They lack the specific adaptations (like bundle sheath cells) that C4 and CAM plants have to minimize photorespiration.

6. **Conclusion**:
- Since PEP carboxylase is involved in both CAM and C4 plants but not in C3 plants, the correct answer is that PEP carboxylase is associated with both CAM plants and C4 plants.

### Final Answer:
- PEP carboxylase is associated with both CAM plants and C4 plants.