BIOL 223 Membrane Potentials - 2
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An ion channel which flows towards the gradients and does not require an energy input is a:
An ion channel which goes against the gradient and requires ATP is known as an:
True or False: Leak channels are specific to certain ions.
Are leak channels mostly open or mostly closed?
Will ions move down or away from their respective gradient through a leak channel?
towards, or down, the gradient
List the four types of passive ion channels discussed in class.
- leak channels
- mechanically gated channels
- ligand-gated channels
- voltage-gated channels
What causes mechanically-gated channels to open?
pressure being applied to the cell
When pressure is removed from a cell, the mechanically-gated ion channels will:
True or False: Ions will flow down the concentration gradient through mechanically-gated channels.
What causes ligand-gated ion channels to open?
the binding of specific neurotransmitters to receptor sites
What must occur for a ligand-gated channel to close?
removal of the neurotransmitter from the receptor site
List the two primary structural compenents of a voltage-gated ion channel.
- activation gate
- inactivation gate
A change in the potential of a cell membrane affects which type of passive ion channel?
Why do active ion channels require ATP?
because they go against, or up, the concentration gradient
The sodium/potassium pump requires one ATP to pump _______ out of the cell against the gradient.
The sodium/potassium pump requires one ATP to pump _______ potassiums_______ the cell, against the gradient.
Small changes in potential that makes the membrane more or less negative are known as:
Will making the membrane potential more negative increase or decrease the polarity of the cell?
increase the polarity
Does an increase in cellular polarity have a stimulatory or inhibitory effect on the cell?
Will making the membrane potential less negative increase or decrease the polarity of the cell?
decrease the polarity
The decrease in polarity of a cell will have an _______ effect.
List the five causes of local potentials discussed in class.
- ligand binding
- mechanical stimulation
- temperature changes
- voltage changes
- spontaneous change in permeability
Small changes in potential that die out and do not result in a change of cellular activity is known as:
When local potentials are larger or have additive effects that result in a change in cell activity, it is an example of:
summation of local potentials
True of False: A local potential will always result in a change in cellular activity.
False - what happens after a local potential is determined by the size of the potential
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