What is the primary CO2 acceptor in the mesophyll cells of C4 plants (such as Maize and Sugarcane)? (Hard)
Answer and explanation
Correct answer: B. Phosphoenolpyruvate (PEP)
- Step 1: C4 plants use a two-cell photosynthetic mechanism (mesophyll and bundle sheath). Step 2. In mesophyll cells, atmospheric CO2 (as HCO3-) is captured by Phosphoenolpyruvate (PEP, a 3-carbon compound) catalyzed by PEP carboxylase. Answer: Phosphoenolpyruvate (PEP). Why not the others: RuBP fixes CO2 in bundle sheath cells where RuBisCO resides; pyruvate is transported back to mesophyll; malate is transported to bundle sheath.
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