Summary
Small intracellular molecules such as cAMP, IP3 and Ca2+ that amplify and spread signals from receptors.
In depth
cAMP is made by adenylyl cyclase and activates protein kinase A. IP3 releases Ca2+ from the ER and DAG activates protein kinase C. Ca2+ itself binds calmodulin to regulate many enzymes, and cGMP mediates vasodilation by nitric oxide.
Because they are small and diffuse fast, they spread signals rapidly and amplify them. They are removed by enzymes like phosphodiesterases (blocked by caffeine and sildenafil).
Frequently asked questions
What is Second Messengers?
Small intracellular molecules such as cAMP, IP3 and Ca2+ that amplify and spread signals from receptors.
Which area of biology covers Second Messengers, and how advanced is it?
Second Messengers is one of the 52 topics in Cell Biology. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Cell Signalling, G Protein-Coupled Receptors, Nuclear Pore Complex.
Can you give an example of Second Messengers?
Caffeine prolongs cAMP signalling, partly explaining its stimulant effect.
What should I learn before Second Messengers?
Work through the Beginner topics in Cell Biology first, such as Cell Theory, Prokaryotic Cell, Eukaryotic Cell, then return to Second Messengers. Advanced topics assume the Intermediate vocabulary.
What topics are related to Second Messengers?
The closest topics to Second Messengers are Cell Signalling, G Protein-Coupled Receptors, Nuclear Pore Complex, Cell Junctions. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Second Messengers?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Second Messengers. To practise the whole of Cell Biology, use the Cell Biology quiz.
How is Second Messengers different from Cell Signalling?
Second Messengers: Small intracellular molecules such as cAMP, IP3 and Ca2+ that amplify and spread signals from receptors. Cell Signalling: Cells detect extracellular ligands with receptors and convert them into responses through signal transduction pathways. Read both side by side and note what each one explains.
How should I study Second Messengers step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Cell Signalling and explain the difference aloud. Finally, take the Cell Biology quiz and come back to this page for any question you miss.