Skip to main content
Back

Stimulatory Adenylate Cyclase GPCR Signaling quiz

Control buttons has been changed to "navigation" mode.
1/15
  • What hormone initiates the stimulatory adenylate cyclase GPCR signaling pathway?
    The hormone epinephrine (also known as adrenaline) initiates the pathway by binding to the beta adrenergic GPCR.
  • What is the first event that occurs when epinephrine binds to the beta adrenergic GPCR?
    Binding of epinephrine causes a conformational shift in the GPCR structure.
  • What happens to the G protein when the GPCR undergoes a conformational change?
    The G protein exchanges GDP for GTP, activating the alpha subunit.
  • After activation, what does the G protein alpha subunit do?
    The activated alpha subunit dissociates from the beta and gamma subunits and diffuses toward the effector enzyme adenylate cyclase.
  • What is the effector enzyme in the stimulatory adenylate cyclase GPCR pathway?
    The effector enzyme is adenylate cyclase.
  • How is adenylate cyclase activated in this signaling pathway?
    Adenylate cyclase is activated when the GTP-bound alpha subunit of the G protein binds to it.
  • What reaction does activated adenylate cyclase catalyze?
    Activated adenylate cyclase converts ATP into the secondary messenger cAMP (cyclic AMP).
  • What is the role of cAMP in this signaling pathway?
    cAMP acts as a secondary messenger that activates protein kinase A (PKA).
  • What cellular responses are triggered by the activation of protein kinase A (PKA)?
    PKA activation leads to cellular responses such as increased breakdown of glycogen and fat, providing energy for the fight or flight response.
  • How is the signal terminated in the stimulatory adenylate cyclase GPCR pathway?
    The alpha subunit hydrolyzes GTP to GDP, inactivating itself and adenylate cyclase, and then reassociates with the beta and gamma subunits.
  • What happens to the ligand (epinephrine) at the end of the signaling cycle?
    The ligand dissociates from the beta adrenergic GPCR, allowing the pathway to reset.
  • Why is this signaling pathway described as a cycle?
    Because it begins and ends with the same components, allowing the process to repeat when a new ligand binds.
  • What is the main physiological purpose of the stimulatory adenylate cyclase GPCR pathway?
    Its main purpose is to prepare the body for a fight or flight response by mobilizing energy stores.
  • What is the significance of the exchange of GDP for GTP on the G protein?
    This exchange activates the G protein, enabling the alpha subunit to interact with and activate adenylate cyclase.
  • What is the relationship between the terms 'stimulatory' and 'adenylate cyclase' in this pathway?
    The term 'stimulatory' refers to the G protein (Gs) that activates adenylate cyclase, leading to increased cAMP production.