Which statement about G proteins is true?
A) G proteins contain only one binding site.
B) When a G protein binds to an activated receptor protein, ADP is exchanged for ATP.
C) G proteins are associated with G protein-coupled receptors, which are transmembrane proteins.
D) G proteins do not become associated with the cell membrane.
E) G proteins are extracellular proteins.

Question

Quizplus · Accepted Answer

G proteins are associated with G protein-coupled receptors, which are transmembrane proteins. This allows for intracellular signaling in response to extracellular signals.

Answer: B
 When a G protein binds to an activated receptor protein, GDP (not ADP) is exchanged for GTP. This activated the G protein and allows it to interact with downstream signaling molecules.

Therefore, the correct answer is C and B.

Which Statement About G Proteins Is True