Biology Chapter 9 Key Terms

programmed cell death

signal that is sent and received by the same or similar nearby cells - E.g. heart cells communicate

a matrix of proteins and sugars protects colonies of pathogenic bacteria from the host immune system

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

long-distance signal that is delivered by ligands (hormones) traveling through an organism's circulatory system from the signaling cell to the target cell

receptor protein that is located in the cytosol of a cell and binds to ligands that pass through the plasma membrane

enzyme that catalyzes the transfer of a phosphate group from ATP to another molecule

molecule produced by a signaling cell that binds with a specific receptor, delivering a signal in the process

signal between nearby cells that is delivered by ligands traveling in the liquid medium in the space between the cells

enzyme that removes the phosphate group from a molecule that has been previously phosphorylated

small, non-protein molecule that propagates a signal within the cell after activation of a receptor causes its release

propagation of the signal through the cytoplasm (and sometimes also the nucleus) of the cell