In cell respiration, the chemical energy in sugar is transferred to ATP. In the process, some of its chemical energy is changed to heat<span>. As with </span>photosynthesis<span>, the amount of energy that enters the system in the chemical bonds of sugar equals the amount transferred to ATP plus the amount changed to </span>heat<span>.</span>
In cellular respiration glucose is converted into ATP (adenosine triphosphate) which is also known as the energy currency of the cell. Glucose enter the catabolic pathway in glycolysis, followed by citric acid cycle and the oxidative phosphorylation pathway. Glucose can enter either the aerobic or anaerobic pathway but the energy yield in the aerobic pathway is several folds higher.
