Cellular Respiration Vs. Photosynthesis

Photosynthesis is the conversion of light energy into chemical energy by living organisms. The raw materials are carbon dioxide and water; the energy source is sunlight; and the end-products are oxygen and (energy rich) carbohydrates, for example sucrose and starch. This process is arguably the most important biochemical pathway, since nearly all life depends on it. It is a complex process occurring in higher plants, phytoplankton, algae, as well as bacteria such as cyanobacteria. Photosynthetic organisms are also referred to as photoautotrophs.

Cellular respiration describes the metabolic reactions and processes that take place in a cell or across the cell membrane to obtain biochemical energy from fuel molecules and the release of the cells' waste products. Energy is released by the oxidation of fuel molecules and is stored as "high-energy" carriers. The reactions involved in respiration are catabolic reactions in metabolism. Plants use photosynthesis to create the energy they need out of water, nitrogen and CO2 (carbon dioxide) and produce the waste gas oxygen. Most animals use cellular respiration to take in oxygen, and through chemical processes create ATP, then exhaling waste CO2.

Both photosynthesis and cellular respiration transform energy. Photosynthesis transforms the energy of sunlight into glucose in two phases: the light reaction and the Calvin Cycle. In cellular respiration, glucose transforms into ATP for use by the cell in two phases: glycolysis and the oxidation of pyruvic acid. An exchange of gasses is an inherent part of photosynthesis and cellular respiration. During photosynthesis, plants use carbon dioxide from the air and release oxygen as a result of the reaction. Other organisms, including humans, use that oxygen to drive cellular respiration, which in turn uses oxygen in the reaction to break down glucose, releasing carbon dioxide as a byproduct. Electron transport chains and chemiosmosis play roles in the process by which ATP is synthesized during photosynthesis and cellular respiration. 
http://www.worsleyschool.net/science/files/photosynthesis/page.html