PHOTOSYNTHESIS VERSUS RESPIRATION. Photosynthesis is an anabolic process.It produces organic molecules (glucose), having in their bonds chemical energy transformed from the radiant energy of the sun. It occurs in the green cells, during the day time,and lead to increase in weight. Respiration is a catabolic process.It breaks organic molecules,releasing their bond energy.It occurs in all organisms ,at all time,and lead to decrease in weight.