BIO-Exam 4: Signal Transduction Flashcards
Glucagon Receptor
A membrane-bound receptor located on liver cells that binds glucagon to initiate signal transduction for glycogen breakdown.
Second Messenger
A small molecule, like cAMP or Ca²⁺, that transmits signals from a receptor to intracellular targets to amplify the signal.
Protein Kinase A (PKA)
An enzyme activated by cAMP; it phosphorylates target proteins to regulate various cellular processes, like glycogen breakdown.
Phosphodiesterase
An enzyme that degrades cyclic nucleotides like cAMP, turning off the signaling pathway
GPCR (G-Protein Coupled Receptor)
A membrane receptor that, upon binding a ligand, activates a G protein to initiate intracellular signaling pathways.
Heterotrimeric G Protein
A G protein composed of three subunits (α, β, γ) that transmits signals from GPCRs to downstream effectors.
Signal Transduction
A series of molecular events that converts an extracellular signal (like a hormone) into a functional response within the cell.
Glycogen Phosphorylase
An enzyme that catalyzes the breakdown of glycogen into glucose-1-phosphate in response to signaling molecules like glucagon.
Signal Amplification
The process where a small initial signal leads to a large, enhanced cellular response, often through second messengers.
Adenylate Cyclase
An enzyme that converts ATP to cAMP, which activates downstream signaling pathways such as PKA activation.
cAMP
A second messenger molecule that activates PKA and regulates various cellular functions, like glycogen breakdown.
Glycogen Synthase
An enzyme that catalyzes the synthesis of glycogen from glucose; its activity is inhibited when glycogen breakdown is activated.
Epidermal Growth Factor (EGF)
A protein that stimulates cell growth, proliferation, and differentiation by binding to its receptor, EGFR.
GAP (GTPase-activating protein)
A protein that accelerates the hydrolysis of GTP to GDP, inactivating G proteins and turning off signaling.
Protein Family
A group of proteins with similar structures and functions, often arising from a common evolutionary ancestor.
Phospholipase C (PLC)
An enzyme that cleaves PIP2 into inositol triphosphate (IP3) and diacylglycerol (DAG), initiating intracellular signaling.
Ras
A small GTPase that acts as a molecular switch, activating signaling pathways involved in cell growth and differentiation.
Kinase Cascade
A series of kinase activations that amplify a signal, typically leading to cellular responses like gene expression.
Gs
A type of G protein that activates adenylate cyclase, increasing cAMP levels and activating PKA.
Phosphatidylinositol Bisphosphate (PIP2)
A membrane lipid that is cleaved by PLC to produce IP3 and DAG, initiating intracellular signaling pathways.
GEF (Guanine nucleotide Exchange Factor)
A protein that activates GTPases like Ras by promoting the exchange of GDP for GTP, thus turning on signaling.
Nuclear Receptor
A type of intracellular receptor that binds to hormones or other signaling molecules and regulates gene expression.
Gq
A G protein that activates PLC, leading to the production of IP3 and DAG, and triggering downstream signaling pathways.
Inositol Triphosphate (IP3)
A second messenger produced by PLC that binds to receptors on the endoplasmic reticulum to release calcium ions.
