4 MAIN PROCESSES
signal transmission : reception : signal transduction : response
SIGNAL TRANSMISSION
cell must synthesize and release signaling molecules
RECEPTION
large proteins that bind with specific signaling molecules (binds on the surface of the cell)
SIGNAL TRANSDUCTION
a cell convert extracellular signal into an intracellular signal and relays the signal
RESPONSE
alteration of some cell process
WAYS CELLS COMMUNICATE
chemical : electric/energy : temporary contact : junctions
CHEMICAL SIGNALS
interleukins : neurotransmitters : growth factors : hormones
INTERLEUKINS
involved in communication between cells of the immune system
NEUROTRANSMITTERS
signal between neurons of the nervous system
GROWTH FACTORS
stimulate cell growth, division, and development
HORMONES
regulate sexual development and reproduction
LOCAL CHEMICAL TRANSMISSION
a local regulator diffuses to target cells
DISTANT CHEMICAL TRANMISSION
hormones are transported to distant target cells
ELECTRICAL/ENERGY SIGNALS
-Cells in the ear receive sound waves and convert them to electrical signals
-Cells in the eye receive light waves and convert them to electrical signals
-Neurons relay electrical impulses and in some cases can send and receive electrical signals
TEMPORARY CELL-CELL CONTACT
cell adhesion molecules (CAM) on the surface of certain immune system cells allow for cells to home to sites of damage and infection
DIRECTLY THRU CELL JUNCTIONS
some cells are joined with junctions allowing signals to flow freely between their cytoplasms
LIGAND
binds to a specific receptor and triggers a response
HYDROPHILIC MOLECULES
bind to protein receptors on the surface of target cells
HYDROPHOBIC MOLECULES
move through the plasma membrane and bind with intracellular receptors found in the cytosol or nucleus
RECEPTOR UP-REGULATION
increases the number of receptors synthesized, and amplifies the signaling molecule's effect
RECEPTOR DOWN-REGULATION
transporting receptors to lysosomes, where they are destroyed
ION CHANNEL-LINKED RECEPTORS
found in the plasma membrane; convert chemical signals into electrical signals; ion channel opens or closes in response to binding of the signaling molecule
G-PROTEIN LINKED RECEPTORS
transmembrane proteins with an outside binding site for a signaling molecule, and an internal binding site for a specific G protein; couple signaling molecules to transduction pathways in the cell
ENZYME LINKED RECEPTORS
transmembrane proteins with a binding site for a signaling molecule outside the cell and an enzyme component inside the cell
TYROSINE KINASE
an enzyme that catalyzes the transfer of phosphate groups from ATP to the amino acid tyrosine on a substrate protein
PROTEIN KINASE
adds phosphate to activate a target
PROTEIN PHOSPHATASE
catalyzes the removal of a phosphate group
INHIBITS NEURAL SIGNALING
GABA ______ when chloride ions enter the cell
INACTIVE
when _______ G protein has one subunit linked to a GDP
GTP
signaling molecule binds to receptor & GDP is replaced by GTP
GTP RELEASES
energy
G PROTEIN IS
deactivated
FIRST
the signaling molecule is the ______ messenger
SECOND
information relayed by G protein to a ______ messenger
SECOND MESSENGER
amplify signals inside the cell
CYCLIC AMP (cAMP)
is a second messenger
PHOSPHOLIPIDS
some G proteins use ______ as second messengers
PIP2
splits into IP3 and DAG
CALCIUM IONS
used for neural signaling by binding to certain proteins that activate enzymes
CALMODULIN
helps regulate metabolism, muscle contraction, memory, inflammation, and apoptosis
GENE EXPRESSION REGULATION
ligand-receptor complex binds to region of DNA → activates/represses genes
INTEGRINS
transmembrane proteins that transduce signals in two different directions
ION CHANNELS
open or close (ex: neurotransmitters)
ENZYME ACTIVITY
is altered (ex: receptors on site blood cells)
SPECIFIC GENE ACTIVITY
may be turned on or off
G-PROTEINS
some tyrosine kinase receptors activate _______
RAS PROTEINS
small G proteins that are active when bound to GTP
MAP KINASE PATHWAY
proteins in the MAP pathway phosphorylate combines to form a transcription factor