29 Questions
What is the probability of a single channel being opened under steady-state conditions?
Po
What must be the sum of the probabilities of a channel being open and closed?
1
Which distribution describes the probability of exactly No channels being opened for N channels?
$BN(N_o) = Po^o (1 - Po)^{N-N_o}$
What does Pc represent in the context of channel gating statistics?
Nc
In channel gating statistics, what is the condition for the probability of a channel being open or closed?
$Po + Pc = 1$
What type of current is elicited by depolarization from rest?
Outward "on" Ig
What current is associated with repolarization?
Inward "off" Ig
At what voltage is the charge movement integral of gating current (Q) 20nC?
-120mV
What does the voltage dependence of the charge movement allow estimation of?
The total number of channels in the cell
According to Boltzman equation, what does the ratio of open to closed channels depend on?
Temperature
What is responsible for revealing the voltage-dependence of the channel?
Gating current
What does the symbol 'C' represent in the context of channel gating kinetics?
Closed state of a channel
Which formula is used to calculate the open probability of a channel?
Po = α / (α + β)
What does the average dwell time for the channel remaining in the open state represent?
Time spent in the open state before transitioning
In the context of channel gating kinetics, what is the probability density function for the dwell time at the closed state based on?
An exponential distribution
What information can be obtained from fitting dwell time histograms in channel gating kinetics?
Rate constants α and β
Which formula is used to calculate the closed probability of a channel?
Pc = β / (α + β)
What is the term used to describe the binary nature of channel gating, where channels exist either in conducting (open) or non-conducting (close or inactivated) state?
Stochastic gating
Which type of channels open in response to ligand-binding, mechanical stimulus, and changes in membrane potential?
Stretch-sensitive channels
What is the term used to describe the loss of channel conductance after activation, even when the activation stimulus is still present?
Stochastic inactivation
What type of channels are constitutively open and do not require a specific stimulus for their opening?
Leak channels
How do voltage-gated channels respond to changes in membrane potential?
By altering their conformation
What attracts the positively charged segment of a voltage-gated channel to the negative interior of the cell?
Depolarization
What is the formula for the mean number of open channels?
No = NPo
How does the variance in the number of open channels relate to the fluctuation in macroscopic channel current?
They are directly proportional
What does the mean macroscopic current formula represent?
Current per channel
Which factor influences the 'noise' in channel properties analysis?
Increase in random openings/closings
What does the point amplitude histogram help analyze?
Fluctuations in macroscopic current
In the point amplitude histogram, what do the peaks represent?
'Noise' amplitude
Test your knowledge on stochastic channel gating, gating mechanisms, gating current, open probability, macroscopic gating kinetics model, and more from Topic 6 of Bioelectricity. Prepare for your assessment with this quiz!
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