Question: how are the chemical equations for photosynthesis and cellular respiration related?
Answer: The products of one process are the reactants of the other. Notice that the equation for cellular respiration is the direct opposite of photosynthesis: Cellular Respiration: C6H12O6 + 6O2 → 6CO2 + 6H2O. Photosynthesis: 6CO2 + 6H2O → C6H12O6+ 6O.