Question

Why does not photorespiration take place in C4 plants?

Answer 1

C₄ Plants do not undergo photorespiration because of PEP carboxylase, since it has high affinity for CO₂.

Answer 2

1. C₄ plants have a special enzyme for accepting the atmosphere CO₂. It can accept CO2 even if it lies 1-2 ppm (parts per million)

2. RUBISCO enzyme of C₃ plants can't accept CO₂ below 50 ppm, hence photorespiration takes place.

3. PEP carboxylase is efficient in CO₂ accepting and hence photorespiration doesn't take place in C₄ plants.

Answer 3

In C₄ plants photorespiration does not occur because C₄ acid from the mesophyll is broken down in the bundle cells to release CO₂ this result in increasing the intracellular conc. of CO₂. So this ensure that the RuBisCO functions as a carboxylase minimizing the oxygenase activity.