LO6 Flashcards
cell signaling includes four steps
- signal transmission
- reception
- signal transduction
- response
when a cell sends a signal in the form of a chemical molecule (a hormone) to another cell
signal transmission
when a target cell receives a chemical molecule
reception
involves complex intracellular pathways that allow the signal to be processed internally
signal transduction
the target cell’s ultimate response to the signal
response
has a receptor that can bind with a specific signal molecule
target cell
signal molecules are usually _____ and can’t cross the plasma membranes
hydrophilic
cells synthesize and secrete signal molecules that are received by target cells
signal transmission
steroid hormones are ______ and cant cross plasma membranes
hydrophobic
protein hormones are ______ and cant cross plasma membranes
hydrophilic
if the transmitting cell and target cell are not in close proximity, the signal molecule
must be transported
signal molecule also known as a
ligand
the receptor is usually an
integral plasma membrane protein
receptors are synthesized and degraded by
lysosomes
receptors for hydrophpic signal molecules are
intracellular in the cytosol or nucleus
signal transduction is _____ to _____ signaling
extracellular to intracellular
during ______ information carried by an extracellular signal molecule is converted into an intracellular signal
signal transduction
intracellular domain of a receptor is altered due to
ligand binding
activates a G protein activates the enzyme
adenylyl cyclase
adenylyl cyclase catalyzes the formation of the
second messenger cAMP
small molecules produced in large quantities that help relay and amplify the signal inside a cell
second messengers
during the signal transduction process the signal is _______
amplified
cAMP activates a
protein kinase
enzymes that activate other proteins by phosphorylating them
kinases
adding a P group
phosphorylating
enzymes that remove P groups from proteins, typically deactivating them
phosphatases
cholera is a disease caused by _________ cell signals
unterminated
What happens when you have cholera
- cholera toxin bind to G protein linked receptors
- Results in the production of too many cAMP that activates too many protein kinases
- kinases control chloride ion channel, allowing too many chloride ions to leave the cells
- water follow by osmosis resultingi n severe diarrhea and dehydration
motor neurons release the nuerotransmitter
acetylcholine(ACh)
Binding opens Na+ channels which may result in
muscle contraction
ion channels can
open or close
enzyme activity may
be changed
genes can be
activated or repressed
binding activates enzymes that assemble
microfilament
_____ hormones convey information to a target cell without crossing the plasma membrane of the target cell
protein
_______ are receptor proteins that bind to DNA and regulate gene expression upon activation
transcription factors
amplify a signal
second messengers
_____ messengers are found inside a cell
second
could be cAMP
second messengers
________ domain transmits the signal to the inside of the cell
intracellular
_______ domain for binding of the ligand
extracellular
