Select the wrongly matched pair with regard to the `C_(4)` cycle.

Options

A. Primary `CO_(2)` fixation - PGA product
B. Site of initial carboxylation-Mesophyll cells
C. Primary `CO_(2)` acceptor - PEP
D. `C_(4)` plant - Maize

Answer

To solve the question of selecting the wrongly matched pair with regard to the C4 cycle, let's analyze each option step by step:

### Step 1: Understand the C4 Cycle
The C4 cycle, also known as the Hatch-Slack pathway, is a photosynthetic process that occurs in certain plants (C4 plants) to efficiently fix carbon dioxide (CO2) in hot and dry environments. It involves the initial fixation of CO2 into a four-carbon compound.

### Step 2: Analyze Each Option
1. **Primary CO2 fixation is carried out by PGA product.**
- This statement is incorrect. The primary CO2 fixation in the C4 cycle is carried out by phosphoenolpyruvate (PEP), which combines with CO2 to form oxaloacetic acid (OAA), not PGA (3-phosphoglycerate). Thus, this is the wrongly matched pair.

2. **Site of initial carboxylation are the mesophyll cells.**
- This statement is correct. The initial carboxylation reaction occurs in the mesophyll cells where CO2 is fixed into oxaloacetate.

3. **Primary CO2 acceptor is PEP.**
- This statement is also correct. PEP (phosphoenolpyruvate) is indeed the primary CO2 acceptor in the C4 cycle.

4. **C4 plant maize.**
- This statement is correct as well. Maize is a well-known C4 plant that has the anatomical features (mesophyll and bundle sheath cells) necessary for the C4 cycle.

### Conclusion
Based on the analysis, the first option is the wrongly matched pair regarding the C4 cycle.

### Final Answer
The wrongly matched pair is: **Primary CO2 fixation is carried out by PGA product.**

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