Cellular respiration and photosynthesis are important parts of the carbon cycle. The carbon cycle is the pathways through which carbon is recycled in the biosphere. While cellular respiration releases carbon dioxide into the environment, photosynthesis pulls carbon dioxide out of the atmosphere.
these are the definitions so hope it helps you:
carbon cycle - Pathways through which carbon is recycled through the biosphere.
cellular respiration - Process of breaking down glucose to obtain energy in the form of ATP.
photosynthesis - Process by which specific organisms (including all plants) use the sun's energy to make their own food from carbon dioxide and water; process that converts the energy of the sun, or solar energy, into carbohydrates, a type of chemical energy.