C3 and C4 plant photosynthesis differ with respect to1) Number of ATP required 2) First product of CO2 fixation3) CO2 acceptor

Both C3 and C4 plants differ w.r.t.  number of ATP required, first product of CO2 and CO2 acceptor. C4 plants require more number of ATP as compared to C3 plants. The first product of CO2 fixation in C3 plants is 2 molecules of PGA while the first product of CO2 fixation in C4 plant is oxaloacetic acid. The first CO2 acceptor in C3 plant is RUBP while PEP is the CO2 acceptor in C4 plants.