In the C4 pathway of carbon fixation, what is the first stable four-carbon compound formed in mesophyll cells?

💡 Solution & Explanation

In the C4 photosynthetic carbon fixation pathway, carbon dioxide is initially captured by phosphoenolpyruvate carboxylase in the mesophyll cells to generate oxaloacetic acid as the first stable four-carbon intermediate. Phosphoglyceric acid is conversely the first stable product in the C3 Calvin cycle pathway. C4 plants like maize and sugarcane exhibit high photosynthetic efficiency under high temperatures and arid conditions.