Question

Primary carboxylation enzyme in $C_4$ plants is found in:

• A. Mesophyll cells
• B. Chloroplast of bundle sheath cells
• C. Cytoplasm of bundle sheath cells
• D. None of these

Answer 1

The correct option is A Mesophyll cells

In $C_4$ plants, the initial carbon fixation step and the Calvin cycle are separated spatially. Carbon fixation occurs via phosphoenolpyruvate (PEP) carboxylation in chloroplasts located in the mesophyll, while malate, the four-carbon product of that process, is transported to chloroplasts in bundle-sheath.