Membrane Bound Receptors and Secondary Messengers - Video Tutorials & Practice Problems
G Protein-Coupled Receptors
Membrane Bound Receptors and Secondary Messengers Example 1
What is the role of G proteins in GPCR signaling?
Catalyzing DNA synthesis.
Initiating apoptosis.
Transcription of mRNA.
Activating downstream effectors.
Amplification
Membrane Bound Receptors and Secondary Messengers Example 2
Hormones can bring about substantial physiological changes at very low concentrations. How does this relate to the concept of second messenger systems?
Second messenger systems act more quickly, creating a larger cellular response.
Second messenger systems modify the DNA directly, allowing the hormone to make an impact even at low concentrations.
Second messenger systems prevent hormones from being degraded so they can exert their effect for a longer duration.
Second messenger systems amplify the original hormone signal, allowing it to work at low concentrations.
Secondary Messengers
Membrane Bound Receptors and Secondary Messengers Example 3
You are studying how a hormone affects a cell and find that when oxytocin binds the receptor, the intracellular Ca2+ concentration increases. Based on this information, what could you logically conclude about this cell and hormone?
The cell uses adenylate cyclase as a second messenger.
Oxytocin directly interacts with the DNA of the cell.
The cell uses IP3​ and DAG as secondary messengers.
Both A & B are correct.
cAMP, IP3​, and DAG are all molecules that are used as secondary messengers. Which statement below correctly identifies a difference between the pathways in which they are found?
cAMP secondary messenger systems result in the activation of a kinase, while systems that use IP3​ and DAG do not.
cAMP and IP3​ are part of the same signaling cascade, while DAG is found in different cascades.
Adenylate cyclase produces cAMP while phospholipase C produces IP3​ and DAG.
Both A & C are correct.