11. If a modified form of GTP that CANNOT be enzymatically converted to GDP were added to a culture of cells, the likely result would be
(A) the inhibition of pathways stimulated by tyrosine-kinase receptors
(B) the inactivation of G-protein-coupled signaling pathways
(C) the inactivation of ligand-gated ion channels
(D) receptor tyrosine kinases would be stimulated by the additional phosphate groups present in the modified GTP
(E) that the activated G proteins would remain locked in the "on" position, transmitting signal even in the absence of a signaling molecule