Question

What is photorespiration? How do autotrophs avoid this problem? (Not about specific plant types, but in general how do autotrophs solve this)

Answer 1

photorespiration is process occur in C3 plant when CO2 concentration is very low (less than 50 ppm). at lower concentration plant use Oxygen instead of CO2 in photosynthesis and give out some CO2 and it is waste process. because RUBISCO enzyme have higher affinity to oxygen than CO2.

to avoid this process C4 plant like maize, sugarcane ,etc have another intermediate process which fix carbon in C4 form. in C4 plant calvin cycle center separate from carbon fixation center. PEP carboxylase in intermediate enzyme present in C4 plant which has higher affinity to CO2 than Rubisco. PEP carboxylase fix Carbon in intermediate organic form and provide continuous supply of CO2 to calvin cylce. in CAM plant photorespiration avoid by changing time of carbon fixation.