How are free radicals naturally generated in the body? A plethora of biochemical activities are constantly taking place inside the human body at any given point in time, most of these activities are highly dependent on energy. Basic biology tells us that the main source of energy used by our cells is glucose. Glucose undergoes a series of metabolic conversions to various products at different stages, culminating in the synthesis of ATP(Adenosine triphosphate).< ATP is simply an energy currency. Yes, much like the US Dollar, the British Pound and even the perpetually weak Nigerian Naira. A currency serves two main purposes : A currency is a store of value and a medium of exchange. The figure below illustrates the production of ATP from glucose. Figure 1. Glucose metabolism ::: Basic medical key ATP AS AN ENERGY CURRENCY Let us examine the structure of ATP a bit closely to glean some information about its characteristics.