A G protein is only active Select one when a phosphate has b
     A G protein is only active  Select one:  when a phosphate has been removed from it  when a kinase has added a phosphate to it  when it has GTP bound to it  when it has been activated by cyclic GMP  when it has GDP bound to it 
  
  Solution
The answer is a. when a phosphate has been removed from it.
you can find the step by step g protein activation:
G-protein with it\'s alpha subunit exposed on the outside surface of the cell and its beta and gamma subunits on the inside surface, binds to a hormone
The alpha sub unit releases GDP
The alpha subunit binds to GTP and separate from the rest of the g protein
Alpha subunit hydrolyzes GTP and a phosphate is lost
Alpha subunit reattaches to the rest of the g protein

