When caffeine binds to adenosine, it causes alertness, but it does not stop the production or build-up of adenosine. So when the caffeine wears off, you have a build-up of adenosine that suddenly ...

This reaction releases a lot of energy, which the organism can then use to build proteins, contact muscles, etc. The reaction product is adenosine diphosphate (ADP), and the phosphate group either ...