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Alberts Cell Bio Ch 11 Lecture 5
Terms in this set (21)
The main difference between ion channels and pores is:
a) channels are not selective
b) channels allow only some ions through
c) they are gated (open and close)
d) b and c
Selectivity of ion channels occurs at which level?
Mechanical channels are triggered by __a__ through the use of ___b__
b. microtubules or microfilaments
The most common type of gated ion channel is the _a__ channel. A channel that opens without stimulation is the ___b____, which allows __c (ion)_ to equilibriate.
b. K+ leak channel
The ion channel that helps the MOST to create the membrane potential is the __.
a. K+ channel
b. Na/K pump
a. K+ channel
b. Na/K pump --contributes to osmolarity--the negative charge inside cell brings in water and Na, so the Na must be removed.
The ions that are high in concentration inside the cells are __a__, while the _b__ concentration is high OUTSIDE cells.
a. K+, HCO3-
b. Na+ and Cl
How is a K+ channel specific for K+?
Dehydration energy matches K+ stabilization energy and is identical to the energy required to remove water, d/t carboxyl groups in the channel. The energy is too HIGH for Na.
Aquaporins prevent H+ from moving in by _a__ in the pore that prevent the proton wire relay. How many water molecules go through at once? b
a. two Asparagines
An electrical activity that is propagated along the entire plasma membrane is called ___a_ or ___a_, consisting of a __b__ wave.
a. action potential or nerve impulse
The depolarization wave means that the cell is becoming __a__ positive, and is self amplifying to create ____b__feedback. This occurs in __c (one/both)__ direction(s) because of inactivation.
a. more (cell at rest has negative value)
b. positive feedback.
Nernst equation allows us to calculate ___.
the theoretical resting potential of membrane.
Find the correct action potential order:
1) K rushes in, cell is now open and resting.
2) the Na channels inactivate
3) stimulus allows Na in
4) Electrical potential shifts about +50 mV
5) K+ channels open (delayed)
6) influx allows more Na in further down
3, 6, 4, 2, 5, 1
What are the two types of glial cells that myelinate __a__ peripheral neurons, and __b__ CNS neurons.
Where are the Na channels located in the neuron? What is the name for this type of conduction?
Node of Ranvier (N = Na)
What do patch clamps measure? a.
Is it measuring the degree of opening or the number of channels that have opened? b
a.The current that flows through a channel.
b.it measures the number of channels
Transmitter gated channels are located _a_ and bind which type of molecules? b
What are the two types of transmitters? c
a. neuron postsynaptic cell
c. Excitatory =open Na channels to create action potential
Inhibitory = open Cl/K channels to suppress action potential
Is the acetylcholine receptor specific to ions?
no, allows many different ions through
1. Which neurotransmitter is not taken back up into the synaptic knob?
2. Which are excitatory (vs inhibitory)?
1. b) acetylcholine is degraded by acetylcholinesterase
2. c (and b sometimes)
Find correct neuromuscular transmission order:
a) Voltage gated Ca channels allow Ca into cell
b) Self propagation from Na creates action potential along entire membrane, activating Ca channels in this new cell.
c) Nerve impulse depolarizes terminal
d) Neurotransmitter is released
e) Sarcoplasmic reticulum channels release Ca into cytoplasm, to cause muscle contraction
f) neurotransmitter binds muscle cell to allow Na in.
c, a, d, f, b, e
The axon hillock performs _a_.
Increased combined PSP (postsynaptic potential) results in __b_frequent firing.
LTP (long term potentiation) refers to __c__, and _d__receptors are involved with it.
The main thing to know about LTP is that the cell ____e___.
a. dense gated ion channel region at axon base,
c. the phenomenon that a constant stimulant will increase sensitivity and cause a more rapid response.
e. Cell responds to LTP by increasing receptor number.
Adaptation after prolonged stimulation in the nerve cell means that the response is decreased by ___.
Ca2+ activated K channels
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