Answer
No, the reaction takes place in a set of individual reactions. Since the reaction leads to a higher ordered state in cell, which comes with more disorder and generation of heat.
Work Step by Step
The photosynthesis reaction takes place in several steps, the equation shown in the question is the bottom line reaction ie the overall reaction.
As stated by the second law of thermodynamics, the increase in order must be accompanied by a greater increase in disorder. And disorder happens because heat is generated at several steps in the reaction.
