BIOL 13100 FINAL EXAM 2024 LATEST QUESTIONS
AND VERIFIED COMPLETE ANSWERS UPDATED AND
GRADED A++
What would happen to axon potential if there was no sodium?
There would be no action potential
Voltage gated sodium channel
Lets sodium in during depolarization
Can be open, closed, or inactive
The m gate is the gate in the middle and the h gate is the one at the end
Delayed rectifier potassium channel
Lets potassium in and out of the cell
It is a delayed response to help the cell membrane depolarize
Only has an n gate which is in the middle
When does the rectifier potassium channel activate?
When the membrane potential is -90
What level does the sodium channel depolarize the membrane to after action
potential is initiated?
+55
The gates at rest
m gate is closed
h gate is open
, n gate is closed
(Membrane potential is -75)
The gates immediately after depolarization
m gate is open
h gate is open
n gate is closed
The gates 2-5 ms after depolarization
m gate is open
h gate is closed at 5 ms (lasts a few seconds)
n gate is open
The gates at hyperpolarization
m gate is closed
h gate is closed
n gate is open
Refractory period
A brief period after a neuron fires where it cannot be fired again due to the inactivation
of sodium channels
How does action potential move along?
It depolarizes the area in front of it and the inactivation of sodium channels as well as
the opening of potassium channels forces it to go forwards
Schwann cells
An axon with myelin wrapped around it
Where are the sodium and potassium pumps in schwann cells? How does this
affect axon potential?
At the nodes. This means there are fewer of them and makes axon potential move
faster because it jumps from one node to the next
Whats the purpose of myelination?
Allows axons to have small diameters and transmit action potentials rapidly
Synapse
The site where an axon makes contact with a cell
How are action potentials initiated?
AND VERIFIED COMPLETE ANSWERS UPDATED AND
GRADED A++
What would happen to axon potential if there was no sodium?
There would be no action potential
Voltage gated sodium channel
Lets sodium in during depolarization
Can be open, closed, or inactive
The m gate is the gate in the middle and the h gate is the one at the end
Delayed rectifier potassium channel
Lets potassium in and out of the cell
It is a delayed response to help the cell membrane depolarize
Only has an n gate which is in the middle
When does the rectifier potassium channel activate?
When the membrane potential is -90
What level does the sodium channel depolarize the membrane to after action
potential is initiated?
+55
The gates at rest
m gate is closed
h gate is open
, n gate is closed
(Membrane potential is -75)
The gates immediately after depolarization
m gate is open
h gate is open
n gate is closed
The gates 2-5 ms after depolarization
m gate is open
h gate is closed at 5 ms (lasts a few seconds)
n gate is open
The gates at hyperpolarization
m gate is closed
h gate is closed
n gate is open
Refractory period
A brief period after a neuron fires where it cannot be fired again due to the inactivation
of sodium channels
How does action potential move along?
It depolarizes the area in front of it and the inactivation of sodium channels as well as
the opening of potassium channels forces it to go forwards
Schwann cells
An axon with myelin wrapped around it
Where are the sodium and potassium pumps in schwann cells? How does this
affect axon potential?
At the nodes. This means there are fewer of them and makes axon potential move
faster because it jumps from one node to the next
Whats the purpose of myelination?
Allows axons to have small diameters and transmit action potentials rapidly
Synapse
The site where an axon makes contact with a cell
How are action potentials initiated?
