Cellular respiration is the process conducted by animal cells to produce energy the cell can use for its life processes. This energy is produced by combining glucose, a simple sugar, with oxygen. This produces energy, in the form of ATP (adenosine triphosphate), and gives off carbon dioxide and water as waste products. This process occurs within the mitochondrion, the energy producing organelle in animal cells. In plant cells, the chloroplast is the organelle responsible for most of the energy production. The process plant cells use is called photosynthesis. This process combines light energy, usually from the sun, with carbon dioxide and water to manufacture energy, which is stored in the form of glucose. Oxygen is given off as a waste product in this process. Between the two processes, a "win-win" relationship exists: animal cells give off carbon dioxide and water as a waste product, which plant cells need. Plant cells, in return, give off oxygen as a waste product, which the animal cells need.
During respiration, the living organism just get the oxygen needed for the cels. But during photosynthesis, food is prepared in the leaves and oxygen is given out separated from the carbondioxide taken in.