Chapter 9 - Cell Communication Flashcards
Purpose of cell-signaling in single-celled organisms
populations are allowed to work together to create a cohesive unit with which to accomplish tasks
Purpose of cell-signaling in multicellular organisms
allows for the specialization of groups of cells within a larger organism –> these cells can band together to create tissues & organs, for example
-also provides the necessary coordination for functionality of migration, differentiation, development, etc.
Receptors
protein molecules upon which a ligand will bind to activate a reaction
Autocrine signaling
cell sending messages to itself –> a cell releases a signal that will attach to a receptor on the same cell
Paracrine signaling
passing signals to nearby/adjacent organisms through the cytoplasm that will still need to attach to a specific receptor on the target cell
-also called local signaling
-ex: chemical neuron synapse
Endocrine signaling
a ligand/signal secreted at one location & will be transported to another distant location via the bloodstream to attach to a specific receptor on the target cell
Direct contact signaling
signals bound to a cell will attach to receptors bound to another adjacent cell
-ex: plasmodesmata, gap junctions
Intracellular/internal receptor
ligands are small, nonpolar, & hydrophobic
-receptors are located very close to the location in which the response will take place –> many occur as transcription factors for DNA
Extracellular/surface receptor
ligands are polar –> transduction will transform the extracellular signal into an intracellular signal
Divergence
one signaling pathway creates 2 separate responses
Convergence
2 separate signals come together to form a single response
Crosstalk
one pathway will inhibit/activate another pathway –> synthesizing input from many signals in order to produce a single response
