Question

Steps of Cyclic adenosine monophosphate to activate (cAMP) (2nd messenger).

a) Production of cAMP, activation of protein kinase, cellular response
b) Synthesis of cAMP, inhibition of protein kinase, cellular response
c) Breakdown of cAMP, activation of protein kinase, cellular response
d) Phosphorylation of cAMP, activation of protein kinase, membrane potential change

Answer 1

cAMP is a second messenger that activates cellular responses through a series of steps: hormone binding, G-protein activation, adenylyl cyclase activation, cAMP production, and kinase activation leading to potential change in the cell.

Step-by-step explanation:

The process by which cyclic adenosine monophosphate (cAMP) acts as a second messenger involves several steps:

1. A water-soluble hormone binds to its receptor in the cell membrane.
2. This receptor activates the associated G-protein.
3. The activated G-protein then activates the enzyme adenylyl cyclase.
4. Adenylyl cyclase converts adenosine triphosphate (ATP) into cAMP.
5. cAMP binds to and activates cAMP-dependent protein kinase (A-kinase).
6. A-kinase phosphorylates serine and threonine residues on target proteins, resulting in a cellular response.

The appropriate sequence of steps culminating in a cellular response initiated by cAMP is option 'a', that is, production of cAMP, activation of protein kinase, followed by a cellular response. This cascade results in the phosphorylation and activation of various cellular proteins, leading to potential change and varied responses in different cells.

To terminate the signal, an enzyme called phosphodiesterase converts cAMP into AMP, thus deactivating the pathway and ensuring that the cell can return to its resting state once the signaling event is over.