89 Key Terms
- apoptosis
- programmed cell death
- autocrine signal
- signal that is sent and received by the same or similar nearby cells
- autoinducer
- signaling molecule secreted by bacteria to communicate with other bacteria of its kind
- cell-surface receptor
- cell-surface protein that transmits a signal from the exterior of the cell to the interior, even though the ligand does not enter the cell
- chemical synapse
- small space between axon terminals and dendrites of nerve cells where neurotransmitters function
- cyclic AMP (cAMP)
- second messenger that is derived from ATP
- cyclic AMP-dependent kinase
- (also, protein kinase A, or PKA) kinase that is activated by binding to cAMP
- diacylglycerol (DAG)
- cleavage product of PIP2 that is used for signaling within the plasma membrane
- dimer
- chemical compound formed when two molecules join together
- dimerization
- (of receptor proteins) interaction of two receptor proteins to form a functional complex called a dimer
- endocrine cell
- cell that releases ligands involved in endocrine signaling (hormones)
- endocrine signal
- long-distance signal that is delivered by ligands (hormones) traveling through an organism’s circulatory system from the signaling cell to the target cell
- enzyme-linked receptor
- cell-surface receptor with intracellular domains that are associated with membrane-bound enzymes
- extracellular domain
- region of a cell-surface receptor that is located on the cell surface
- G-protein-linked receptor
- cell-surface receptor that activates membrane-bound G-proteins to transmit a signal from the receptor to nearby membrane components
- growth factor
- ligand that binds to cell-surface receptors and stimulates cell growth
- inhibitor
- molecule that binds to a protein (usually an enzyme) and keeps it from functioning
- inositol phospholipid
- lipid present at small concentrations in the plasma membrane that is converted into a second messenger; it has inositol (a carbohydrate) as its hydrophilic head group
- inositol triphosphate (IP3)
- cleavage product of PIP2 that is used for signaling within the cell
- intercellular signaling
- communication between a cell
- internal receptor
- (also, intracellular receptor) receptor protein that is located in the cytosol of a cell and binds to ligands that pass through the plasma membrane
- intracellular mediator
- (also, second messenger) small molecule that transmits signals within a cell
- intracellular signaling
- communication within cells
- ion channel-linked receptor
- cell-surface receptor that forms a plasma membrane channel, which opens when a ligand binds to the extracellular domain (ligand-gated channels)
- kinase
- enzyme that catalyzes the transfer of a phosphate group from ATP to another molecule
- ligand
- molecule produced by a signaling cell that binds with a specific receptor, delivering a signal in the process
- mating factor
- signaling molecule secreted by yeast cells to communicate to nearby yeast cells that th