[Campbell Biology P.267] Which of the following statements accurately describes a step in th... | Practice Question

Which of the following statements accurately describes a step in the G protein-coupled receptor GPCR signaling pathway, based on the provided diagram and text?

  • A: The inactive G protein always binds to an enzyme first before interacting with the receptor.
  • B: Signaling molecule binding to the receptor directly causes the conversion of GDP to GTP on the G protein.
  • C: The activated G protein dissociates from the receptor, diffuses along the membrane, and then binds to an enzyme.
  • D: GTP hydrolysis occurs on the enzyme, which then releases the G protein and returns to its inactive state.

Explanation

According to step 3 in the diagram and accompanying text, the activated G protein indeed dissociates from the receptor, diffuses along the membrane, and then binds to an enzyme, altering its activity to trigger a cellular response.