23 Questions
Ion channels facilitate what kind of movement of ions across membranes and what kind of pathway for ions to move through the lipid core of the membrane?
passive and polar
What is a pore?
provides polar a polar pathway for movement of ions
What is a gate?
regulates the movement of ions through the pore
What is permeation?
properties describing the movement of ions through a pore
What is gating?
properties describing the opening and closing of the pore
Channel Gating....
greatly increases the time the channel is open or closed such as ligand binding or voltage change
Which of the following best describes a reversible process in ion channels?
Channels open and close randomly
What determines whether an ion channel is open or closed at any given time?
Random chance
How do membrane stimuli affect the probability of ion channel opening or closing?
They change the channel's conformation
Which type of ions move with the field in a membrane?
Anions
What is the unit of measurement for current?
Amps
What happens to the cell interior during hyperpolarization?
It becomes more negative
Which of the following best describes the rate of a First order process in ion channels?
The rate is determined by the opening rate
What is the average dwell time in the open state of an ion channel?
1/kb
What is the effect of ligand binding on ion channel opening probability?
Ligand binding increases open probability
Which ion is higher inside the cell than outside, making it easier to send more of this ion inside the cell?
Potassium
What is the driving force for ion currents in the cell membrane?
Voltage difference
What is the term used to describe the large change in inward current for a small change in voltage, and very little change in outward current for a change in voltage?
Rectification
Which ion is higher inside the cell than outside, making it easier to send more of this ion inside the cell?
Potassium
What is the driving force for ion currents in the cell membrane?
Electrical potential
What is the term used to describe the large change in outward current for a small change in voltage, and very little change in inward current for a change in voltage?
Hyperpolarization
What is the unit of measurement for current?
Ampere
What is the effect of hyperpolarization on the cell membrane?
It generates capacitive currents
Test your knowledge on ion channels and membrane permeability. Explore concepts such as ion movement across membranes, pathways for ions through the lipid core, the meaning of pore and gate, and the processes of permeation and gating.
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