Question

C4 plants ultimately use RUBISCO, yet have lower rate of photo respiration than do C3 plants. Why?

Answer 1

C₄ plants prevent photorespiration because they increase the concentration of CO₂ at the site where the enzyme RUBISCO is present. ​ RUBISCO uses up oxygen only when concentration of oxygen is more than that if carbon dioxide at the site where enzyme is present.The C₄ acid in the mesophyll cells are broken to produce CO₂ in the bundlesheath cells not in the mesophyll cells themselves. This increases the intracellular concentration of carbon dioxide and ensures that the carboxylase activity of ​ RUBISCO is maintained and oxygenase activity does not start.