Home › SMLE (Saudi Medical Licensing) › Physiology › The Endocrine System › In the cAMP second messenger system, the activat…
In the cAMP second messenger system, the activated G protein switches on which enzyme?
APhosphodiesterase
BPhospholipase C
CProtein kinase
DAdenylyl cyclase
Answer & Solution
Correct answer: D. Adenylyl cyclase
1. A water-soluble hormone binds a membrane receptor associated with an intracellular G protein.
2. Hormone binding activates the G protein, which activates adenylyl cyclase.
3. Adenylyl cyclase then converts ATP into cAMP, the second messenger.
4. cAMP activates a protein kinase, so the kinase sits one step later in the chain, not next to the G protein.
5. Phosphodiesterase ends the signal by degrading cAMP, and phospholipase C belongs to the calcium pathway instead.
_Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 17 "The Endocrine System", section 17.2 Hormones_
Related questions
From which embryonic tissue does the anterior pituitary gland arise?The kidneys release erythropoietin in response to what?Stretching of the atrial wall releases atrial natriuretic peptide. What does that hormone Glucagon makes the liver take up amino acids and convert them into glucose. What is this rWhich cells take up glucose without needing insulin at all?Insulin appears to act through which kind of receptor?Insulin raises glucose uptake mainly through which cellular action?Between which two values is blood glucose concentration tightly maintained?