G-proteins A signal receptor protein in the plasma membrane that

Ion channels
A signal receptor protein in the
plasma membrane that responds to
the binding signal molecule by
activating a G protein.
like a light switch: in the “on”
position, a connection is made
with the energy source; in the “off”
position, there is no driving energy.
An enzyme that catalyzes the transfer
of phosphate groups from ATP to the
amino acid tyrosine on a substrate
like a friend who brings together two
people who
otherwise don’t hang out (unless it’s
with this friend); the three have a
great time whenever they are
Protein channel in a cell membrane
that allows passage of a specific ion
down its concentration gradient.
like automatic double doors through
which large crowds
can flow or not flow, depending on if
the doors are open or closed.
situated or occurring inside a cell or
like undercover cops hidden in a
After a protein has been created it is
modified by protein kinase by the
adding a covalently bound phosphate
like flipping the switch of a
mechanical toy
which goes at full speed when it is
turned on and is completely still
turned off.
Calcium ions
Cyclic AMP
It plays an important role in signal
transduction pathways, where it acts
as a second messenger
Cyclic adenosine monophosphate, a
ring-shaped molecule made from
ATP that is a common intracellular
signaling molecule (second
messenger) in eukaryotic cells (for
example, in vertebrate endocrine
cells). It is also a regulator of some
bacterial operons.
like students contacting the school’s
Activities office to elicit changes in
the activities calendar.
like drinking caffeinated drinks, if
you sip the caffeinated
drink over a long period all day, it
will not cause a stimulant response,
if you increase the level of caffeine in
the body quickly, it causes activity to
like the trigger on a water gun, each
time the trigger is
pulled the reaction is immediate and
temporary; cAMP is produced each
time there is a cell signal stimulant
(such as epinephrine), but the cAMP
does not stay present long.
The synthesis of RNA on a DNA
The strengthening of stimulus energy
that is otherwise too weak to be
carried into the nervous system.
like when the student council
petitions for a permanent
change in the school rules so that
things can be done in a new way.
like when a new trend hits the
campus and everyone—
students, teachers, administrators,
parents—gets into it.