AP BIOLOGY

Detailed explanation-1: -Second messengers are intracellular signaling molecules released by the cell in response to exposure to extracellular signaling molecules-the first messengers.

Detailed explanation-2: -Adenosine 3′, 5′-cyclic monophosphate (cAMP) is a nucleotide that acts as a key second messenger in numerous signal transduction pathways. cAMP regulates various cellular functions, including cell growth and differentiation, gene transcription and protein expression.

Detailed explanation-3: -Second messengers are molecules that relay signals received at receptors on the cell surface-such as the arrival of protein hormones, growth factors, etc.-to target molecules in the cytosol and/or nucleus.

Detailed explanation-4: -The activation of multiple target enzymes by a single second messenger molecule further amplifies the signal. Second messengers are not only produced in response to extracellular stimuli, but also in response to stimuli from within the cell.