Pharmaceutical researchers can look for potential drugs that target G-protein coupled receptors (GPCRs) by using cell lines that have been engineered to make a particular GPCR and a jellyfish-derived protein called aequorin, which emits blue light proportional to Ca^2+ concentration. Cells making both of these proteins are plated in 96 well plates, and then each well in the plate is treated with compounds that may activate the GPCR made by those cell lines. a. When choosing a GPCR to test using this system, should you select a GPCR that activates a G_s, G_i, or G_q protein? Explain. b. Diagram the steps that occur after an active ligand that binds to the GPCR you are testing that result in Ca^2+ release in the cytosol. Include a narrative to explain the steps shown in the diagram.