Rubisco is an enzyme that acts both as a carboxylase and oxygenase. Why do you think the Rubisco carries out more carboxylation in C4 plants ?
Rubisco: (a) Carboxylation in dark reaction involve enzyme RuBP Carboxylase (Rubisco). It is the chief enzyme of photosynthesis.
(b) It initiates photorespiration in C3 plants and not in C4 plants. It has much higher affinity to CO2 than for the oxygen.
© In sugarcane, one type of chloroplasts are found in bundle sheath and other type in mesophyll cells.
(d) RuBP is CO2 acceptor in the presence of enzyme Rubisco to form 6-C-compound which splits into 3-phosphoglycric acid.
(e) RuBP carboxylase acts as RuBP oxygenase when CO2 concentration is high.
(f) It oxidises Ribulose 1, 5, diphosphate into phosphoglyceric acid and glycolate.
(g) Rubisco acts as carboxylase and is helpful in the
formation of carbohydrates in plants.