Question

In $C_4$ plants, the synthesis of malic acid during carbon dioxide fixation occurs in ___________.

• A. guard cells
• B. bundle sheath
• C. mesophyll cells
• D. hypodermis

Answer 1

The correct option is C mesophyll cells

In $C_4$ plants, the synthesis of malic acid during carbon dioxide fixation occurs in mesophyll cells. Mesophyll cells lack the RuBisCO enzyme. The enzyme responsible for fixation is PEPcase. The malic acid formed is transported to bundle sheath cells for decarboxylation i.e., carbon dioxide is released. This carbon dioxide enters the Calvin cycle.