Complex sentence: G proteins are so called because they function as "molecular switches," alternating between an inactive guanosine diphosphate (GDP) and active guanosine triphosphate (GTP) bound state, ultimately going on to regulate downstream cell processes.
Split into simpler sentences: G proteins are so called because they function as "molecular switches". They alternate from'inactive' guanosine diphosphate (GDP) to'active' guanosine triphosphate (GTP), which is a binding state, and which proceeds to regulate downstream cell processes.