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Chapter 13 Study Exam Questions With
Correct Answers.
What is required to open AMPA receptors and allow the influx of positive charges and thus
membrane depolarization? - answer✔✔AMPA receptors open when they bind glutamate.
What is required to open NMDA receptors that allow the influx of positive charges and thus
membrane depolarization? - answer✔✔NMDA receptors have two requirements. The first is that
the receptor has to bind glutamate, which opens the conductive pore in the receptor. The second
is that the membrane has be depolarized by about 20 mV. The more positive membrane potential
then expels the magnesium ion that normally plugs the pore of the receptor. Thus, the receptor
can conduct current only when it binds glutamate and when the magnesium ion is expelled from
the pore.
What ions are AMPA receptors permeable to and what ions are NMDA receptors permeable to?
- answer✔✔AMPA receptors are permeable to both sodium and potassium and when open, drive
the membrane potential to the reversal potential, which is about -2.0 or 0 mV. The pore of the
NMDA receptor is larger, and is permeable to sodium, potassium and most importantly to
calcium.
Define long term potentiation (LTP) and how does it differ from long term depression (LTD). -
answer✔✔LTP is the strengthening of a synapse due to a high rate of activity in the presynaptic
neuron. LTD is exactly the opposite, that is it is the weakening of a synapse due to a low rate of
activity in the presynaptic neuron.
What is CaM-Kinase II and where is it located in the synapse? - answer✔✔CaM-Kinase II is an
enzyme activated by calmodulin, but only after the calmodulin has bound calcium. It is located
in the postsynaptic density, just below the synaptic region of the postsynaptic cell.
What is the structure of CaM-Kinase II? - answer✔✔The enzyme is composed of 12 subunits,
where each subunit has both a catalytic domain, and an autoinhibitory domain. The catalytic
domain contains a substrate binding site, the S-site, that can bind to and phosphorylate a
substrate, and a T-site on the autoinhibitory domain. The full-length form of the kinase has
almost no catalytic activity under basal conditions because the autoinhibitory domain of each
subunit binds to its own catalytic domain, thereby closing the subunit and inhibiting its catalytic
activity. Binding of ca++/calmodulin to the autoinhibitory region opens the subunit and renders
Chapter 13 Study Exam Questions With
Correct Answers.
What is required to open AMPA receptors and allow the influx of positive charges and thus
membrane depolarization? - answer✔✔AMPA receptors open when they bind glutamate.
What is required to open NMDA receptors that allow the influx of positive charges and thus
membrane depolarization? - answer✔✔NMDA receptors have two requirements. The first is that
the receptor has to bind glutamate, which opens the conductive pore in the receptor. The second
is that the membrane has be depolarized by about 20 mV. The more positive membrane potential
then expels the magnesium ion that normally plugs the pore of the receptor. Thus, the receptor
can conduct current only when it binds glutamate and when the magnesium ion is expelled from
the pore.
What ions are AMPA receptors permeable to and what ions are NMDA receptors permeable to?
- answer✔✔AMPA receptors are permeable to both sodium and potassium and when open, drive
the membrane potential to the reversal potential, which is about -2.0 or 0 mV. The pore of the
NMDA receptor is larger, and is permeable to sodium, potassium and most importantly to
calcium.
Define long term potentiation (LTP) and how does it differ from long term depression (LTD). -
answer✔✔LTP is the strengthening of a synapse due to a high rate of activity in the presynaptic
neuron. LTD is exactly the opposite, that is it is the weakening of a synapse due to a low rate of
activity in the presynaptic neuron.
What is CaM-Kinase II and where is it located in the synapse? - answer✔✔CaM-Kinase II is an
enzyme activated by calmodulin, but only after the calmodulin has bound calcium. It is located
in the postsynaptic density, just below the synaptic region of the postsynaptic cell.
What is the structure of CaM-Kinase II? - answer✔✔The enzyme is composed of 12 subunits,
where each subunit has both a catalytic domain, and an autoinhibitory domain. The catalytic
domain contains a substrate binding site, the S-site, that can bind to and phosphorylate a
substrate, and a T-site on the autoinhibitory domain. The full-length form of the kinase has
almost no catalytic activity under basal conditions because the autoinhibitory domain of each
subunit binds to its own catalytic domain, thereby closing the subunit and inhibiting its catalytic
activity. Binding of ca++/calmodulin to the autoinhibitory region opens the subunit and renders
