Question

Select the correct option:

The reaction that is responsible for the primary fixation of $C{O}_2$ is catalysed by

• A. RuBP carboxylase
• B. PEP carboxylase
• C. RuBP carboxylase and PEP carboxylase
• D. PGA synthase

Answer 1

The correct option is C RuBP carboxylase and PEP carboxylase

Carbonation is the addition of carbon dioxide to an acceptor. Photosynthetic carboxylation requires ribulose-1, 5-biphosphate or RuBP as acceptor of carbon dioxide and RuBP- Carboxylase oxygenase as enzyme in $C_3$ plants In $C_4$ plants, initial fixation of$C{O}_2$ occurs in mesophyll cells, The primary accept or of $C{O}_2$ is phosphoenol pyruvate which combines with $C{O}_2$ in presence of PEP carboxylase to form oxaloacetic acid or oxaloacetate. So, the correct answer is 'RuBP carboxylase and PEP carboxylase'.