Cellular respiration under aerobic conditions oxidizes glucose to produce carbon dioxide and energy for cellular functions. In the pre-photosynthesis atmosphere anaerobic cellular respiration was most common because there was little oxygen. Sulfur, nitrogen and inorganic carbon were used instead of oxygen for respiration. As photosynthesis increased the oxygen available, the protective layer of ozone in our atmosphere formed to begin filtering out x-rays and some UV light, and aerobic respiration became common. In aerobic respiration sugar, oxygen and water are oxidized to make carbon dioxide and water and energy. Hydrogen electrons are transferred from carbon to oxygen. C6H12O6+6O2+6H2O? 6CO2+12 H2O + energy.
Organism respiration is respiration on an organism scale using gills, skin, or lungs where the blood vessels are close to the surface to expel carbon dioxide produced by the cells and bring in oxygen for aerobic cellular respiration.