Question

The first carbon fixation in $C_4$ pathway occurs in chloroplast of

• A. Guard cells
• B. Mesophyll cells
• C. Bundle sheath cells
• D. Epidermal cells

Answer 1

Answer: (B)

Mesophyll cells

The first carbon fixation in $C_4$ pathway occurs in mesophyll cells. Mesophyll cells are the specialised cells present within a leaf, below epidermal layer. The first step in the pathway is the conversion of pyruvate to phosphoenolpyruvate (PEP), by the enzyme pyruvate orthophosphate dikinase.

So, the correct answer is option B.