Final answer:
When both the alpha and beta/gamma subunits of the G-protein are activated, different cellular responses can occur. One response involves the production of cAMP and a phosphorylation cascade that alters gene expression. Another response involves the release of calcium ions as secondary messengers.
Step-by-step explanation:
When both the alpha and beta/gamma subunits of the G-protein are activated, different cellular responses can occur. In one scenario, the alpha subunit can activate adenylyl cyclase, leading to the production of cAMP. This can trigger a phosphorylation cascade that ultimately alters gene expression. In another scenario, the alpha subunit can activate phospholipase C, leading to a flood of calcium ions which act as secondary messengers.