Starting with a hydrophilic signaling molecule, describe the process that takes place with a G-coupled protein signaling pathway.  Assume that cAMP is your main secondary messenger.   

Be sure to include in your answer:

1) a description of the receptor

2) a description of the structure of the G-protein (inactive and active form)

3) the function of the enzyme in the production of the secondary messenger

4) what your secondary messenger goes on to do in the cell to perpetuate the original signal

5) how the signal is terminated.