Class 11 NEET Biology Photosynthesis in Higher Plants

(d) In C4 plants, initial fixation of carbon dioxide occurs in mesophyll cells. The primary acceptor of CO2 is phosphoenol pyruvate or PEP. It combines with carbon dioxide in the presence of PEP carboxylase to form oxaloacetate.
C4 plants are more efficient in picking up CO2 even when it is found in low concentration because of the high affinity of PEP case.