AP BIOLOGY

Detailed explanation-1: -Calcium and cyclic AMP are familiar second messengers that typically become elevated inside cells on activation of cell surface receptors.

Detailed explanation-2: -Calcium ion (Ca(2+)) plays an important role in stimulus-response reactions of cells as a second messenger.

Detailed explanation-3: -Cyclic AMP (cAMP) and calcium (Ca2+) are arguably the prototypical second messengers that control cellular homeostasis. Whereas, for instance, nitric oxide and cyclic GMP may serve essential functions in a number of physiological situations, cAMP and Ca2+ are the only truly ubiquitous second messengers.

Detailed explanation-4: -(A) cAMP is the archetypical second messenger. Its levels increase rapidly following receptor-mediated activation of adenylyl cyclase (AC), which catalyzes the conversion of adenosine monophosphate (AMP) to cAMP.

Detailed explanation-5: -Cyclic AMP (cAMP) is an intracellular second messenger to a wide variety of hormones and neurotransmitters. In T cells, elevated cAMP levels antagonize T cell activation by inhibiting T cell proliferation and by suppressing the production of IL-2 and IFN-.