what is c3 photosynthesis
C3 Photosynthesis. Plants which use only the Calvin cycle for fixing the carbon dioxide from the air are known as C3 plants. In the first step of the cycle CO 2 reacts with RuBP to produce two 3-carbon molecules of 3-phosphoglyceric acid (3-PGA).his loss to the system is why C3 plants will outperform C4 plants if there is a lot of water and sun. The C4 plants make some of that energy back in the fact that the rubisco is optimally used and the plant has to spend less energy synthesizing rubisco.