Final answer:
GTP binding proteins, also known as G-proteins, act as molecular switches inside cells and are regulated by the binding of receptor-ligand complexes. They play a crucial role in cell signaling.
Step-by-step explanation:
GTP binding proteins, also known as G-proteins, act as molecular switches inside cells and play a crucial role in cell signaling. They are a type of regulatory protein that helps transmit signals from the exterior to the interior of cells. G-proteins are regulated by the binding of receptor-ligand complexes and undergo a cycle of GTP binding and hydrolysis to regulate downstream signaling events.