Question

PEP is primary $C{O}_2$ acceptor in

• A. $C_4$
• B. $C_3$
• C. $C_2$
• D. both $C_3$ and $C_4$ plants

Answer 1

The correct option is A $C_4$

In $C_4$ plants, initial fixation of $C{O}_2$ or carboxylation occurs in mesophyll cells. The chloroplasts of mesophyll cells possess enzyme PEP carboxylase (or PEP case) for initial fixation of $C{O}_2$ .The primary acceptor of $C{O}_2$ is phosphoenol pyruvate or PEP. It combines with $C{O}_2$ in the presence of PEP carboxylase (or PEP case) to form oxaloacetic acid or oxallocetate (OAA). So, the correct answer is 'C4'.