PEPcase is associated with

Options

A. `C_3` plants
B. `C_4` plants
C. `C_2` plants
D. Both B and C

Answer

**Step-by-Step Solution:**

1. **Understanding PEPcase**: PEPcase, or Phosphoenolpyruvate carboxylase, is an enzyme that plays a crucial role in the process of photosynthesis, particularly in certain types of plants.

2. **Identifying the Cycle**: PEPcase is primarily associated with the C4 cycle of photosynthesis. This cycle was discovered by researchers Hatch and Slack, and it is also known as the Hatch-Slack pathway.

3. **Role of PEPcase in C4 Plants**: In the C4 cycle, the primary molecule that accepts carbon dioxide (CO2) is Phosphoenolpyruvate (PEP), which is a 3-carbon compound. PEPcase catalyzes the reaction where CO2 is fixed to PEP, resulting in the formation of a 4-carbon compound, specifically oxaloacetic acid.

4. **Comparison with C3 Plants**: In contrast, C3 plants utilize a different enzyme called Ribulose bisphosphate carboxylase/oxygenase (Rubisco) and a 5-carbon compound called Ribulose bisphosphate (RuBP) to fix CO2. This highlights the distinct pathways in C3 and C4 plants.

5. **Conclusion**: Therefore, PEPcase is specifically associated with the C4 cycle of photosynthesis in C4 plants, where it facilitates the initial fixation of CO2.

**Final Answer**: PEPcase is associated with the C4 cycle of photosynthesis in C4 plants.

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