Question

Which of the following is not involved in signal transduction by the -adrenergic receptor pathway?

A) ATP
B) Cyclic AMP
C) Cyclic GMP
D) GTP
E) All of the above are involved.

Answer 1

Cyclic GMP (cGMP) is not involved in the β-adrenergic receptor pathway; instead Cyclic AMP (cAMP) is the secondary messenger used in this pathway to activate Protein Kinase A. Therefore correct option is C

Step-by-step explanation:

Among the given options, the molecule not involved in signal transduction by the β-adrenergic receptor pathway is Cyclic GMP (cGMP). The β-adrenergic receptor pathway involves the conversion of ATP to Cyclic AMP (cAMP) by the enzyme adenylyl cyclase. This cAMP then acts as the secondary messenger that further activates Protein Kinase A (PKA), which leads to various cellular responses. cGMP, on the other hand, is a different cyclic nucleotide that serves as a secondary messenger in other pathways, not the β-adrenergic receptor pathway.

Additionally, Adenosine Triphosphate (ATP) is the precursor of cAMP, and Guanosine Triphosphate (GTP) is involved in the activation of the G-protein that in turn activates adenylyl cyclase.