hormones and multicellularity Flashcards
agonist vs antagonist
agonist - bind to receptors
and have the same effect as
the ligand but are not the
same chemical as the ligand
antagonist - bind to receptors
and prevent the ligand from
binding, thereby causing
inhibition (they do not cause
signal transduction)
autocrine
diffuse and affect
the cells that produce them
juxtacrine
only effect cells
that are adjacent (in contact with) to
the cell that produced them
paracrine
affect nearby cells
hormonal signaling
3 kinds of membrane receptors
- Ion channels
- Protein kinase receptors
- G-protein coupled receptors
continuous activation of ras
signaling 3 steps
- The signal must bind to the cell surface receptor; embedded on the outside
of the cell membrane - The signal conveys a message to the cell
- The cell changes its response to the signal
* In multicellular organisms this allows cells to work together; signaling
can change how the organism functions
signal transduction pathway
a series of chemical and molecular
events that lead to a cell’s
response to a signal
examples that organisms respond to
light,
temperature, sound, and
touch
crosstalk-
hat is different pathways can interact
.can activate one pathway and inhibit another
receptor-
is a protein that recognizes
a specific signal
ligand
is the chemical that fits the
three-dimensional site on the protein,
and following a conformational change
in the protein causes a response
what is adenosine
a ligand that reduces brain activity including wakefulness therefore caffeine is antagonistic to adenosine
Membrane receptors
se the lipid bilayer (i.e. insulin cannot traverse the cell membrane but instead binds to a transmembrane receptor with an extracellular binding domain)
intracellular receptors
some hormones such as estrogen
can bind to receptors located
inside the cell
