What molecule is main function of cellular respiration?
Glucose is the main product of photosynthesis, and it has all the stored energy from the process. The point of cellular respiration is to break down this molecule and convert its energy into ATP which is the usable energy of the cell. Essentially, the glucose provides the source of the "fuel" that runs cellular activities.
The main purpose of photosynthesis is to generate carbohydrates from atmospheric CO2. The main contribution of photosynthesis is the liberation of O2 back to the atmosphere. The central purpose of cellular respiration is the production of ATP molecules that are necessary for the most metabolic pathways in organisms. The secondary product of cellular respiration is a molecule of H2O.