G Protein-Coupled Receptors (GPCRs): These are proteins on cell membranes that interact with signaling molecules outside the cell and trigger responses inside the cell, often involving production of cAMP.
Protein Kinase A (PKA): An enzyme activated by cAMP that regulates various cellular functions by adding phosphate groups to specific proteins.
Signal Transduction:The process by which a chemical or physical signal is transmitted through a cell via a series of molecular events, often involving enzymes like PKA.