Part one of term paper
As can be seen above, caffeine consists of two carbon/nitrogen rings with oxygen and methyl groups as substituents. The fused rings are similar to those in adenine only the substituents differ. Caffeine is found in coffee, tea, and many soft drinks. There is also some amount of caffeine in chocolate, as well as a closely related stimulant, ...

Part two of term paper
... two only occur at unrealistically high levels of caffeine in the body. The first of these methods, and the most important, is blocking adenosine receptors. As caffeine has a similar structure to the adenosine group, but also has more heavily electrophilic and nucleophilic functional groups than adenosine as, for instance, seen in cyclic AMP. This means that caffeine will fit adenosine receptors as well as adenosine itself will. Thus, cyclic AMP remains active, rather than being broken down. Se ...