But how is amplification actually achieved in this stage? Well, a single epinephrine molecule, when it binds to this single structure, it not only induces the change of this g protein, it also induces the change of many other g proteins found in close proximity. And so not only this will this alpha domain, lose the GDP and bind the GTP. But also nearby alpha domains on other structures, on other seven TM domains will also expel that GDP and bind the GTP. So a single Epinephrine can cause many G proteins to exchange the GTP for the GDP and this causes an Amplification effect. This is the first level of Amplification.