In the previous lesson you mapped the elements needed by a fire in order to burn to those needed by the mitochondria to" burn " glucose. An important point about energy is that it is not created but transformed from one form to another or transferred from one substance to another.

Think back on the lessons we did on energy at the beginning of this unit. Whatever goes into the reaction is transformed, not lost.

Sometimes energy is transferred rather than transformed. This occurs when energy held in a chemical is transferred to another chemical.

It is the same with the products that are used in the mitochondria to produce ATP which is a molecule that holds energy for the cell. During the reaction some of the energy is given off or transformed into heat. At the same time the chemical elements are combined in a new way to produce a different substance and in the process transfer the energy held in the glucose to the high energy bond in ATP.