Within the cell are many mitochondria - these are structures which are the sites for aerobic respiration, prodiving energy by converting ADP (adenosine di-phosphate) into ATP (adenosine tri-phosphate) with this reaction: C6H12O6 + 6O2 --> 6H2O + 6CO2 (glucose + oxygen --> water + carbon dioxide). The mitochondria act as the 'power stations' for the cell. Sorry for not using correct subscript notation in the symbol equation, but I can't see how to do it on this website.