CBNS120 MIDTERM 1 QUESTIONS WITH VERIFIED
ANSWERS
Correct 121
Incorrect 00
1 of 121
Term
What happens as number of channel units increases?
Give this one a try later!
the diameter of the aq. pore
as external k increase injury potential
increases... so ion selectivity
decrease
decreases
the number of ion channels the size of the membrane increases...
decreases... so ion flow increases so ion permeability decreases
Don't know?
2 of 121
,Term
How are APs slightly different in sensory neurons?
Give this one a try later!
They are triggered only in sensory They are triggered in the dendrites
organs outside the nervous system. before reaching the cell body.
They are triggered farther along
a neuron before myleination They are triggered at the axon
begins on the axon (they are terminal after myelination.
pseduo-unipolar)
Don't know?
3 of 121
Definition
very selective neurotoxins label their corresponding channel proteins
using radioactive tags which can help purify a specific ion channel
from channel rich tissue. Purification can help us know the molecule's
size and gross chemical makeup. This is common for Na and K
channels.
Give this one a try later!
, How does an unequal distribution of Why does potassium contribute to
ions produce a resting Em? membrane pot but Cl doesnt?
How does toxin labeling and
What are the 3 families of channels
purification of a channel protein
and some examples?
work?
Don't know?
4 of 121
Term
What are the important features of Nicotinic Acetylcholine receptors
(nAChR)? (subunits, binding sites, selectivity)
Give this one a try later!
1. chemical excitatory
2. chemical inhibitory
3. electrical
Toxin labeling and purification of channel proteins & purification of mRNA coding
for desired channel proteins.
metabolic, structural, and energy requirements limit size. ex: jumbo squid has bigger
axons than larger giant squid. size doesnt mean bigger axons.
, nAChR has 5 subunits - 2 α, 1 β, 1 γ, 1 δ
There are two ACh binding sites, one on each of the α subunits. The outer
vestibule on extracell side of channel has a diameter of 20Å, but the channel
pore narrows down to 7Å at the selectivity filter in the transmemb
region.Cation selectivity due to negatively charged ring of aa residues in
transmemb region
-4 membrane spanning sequences
Don't know?
5 of 121
Term
What is PERMEABILITY?
Give this one a try later!
(P) refers to the ease with which ions can pass through an open membrane
channel. Open channel = permeability
(I) refers to the amount of actual ion movement through a channel under the
influence of a driving potential. Open channel + ions + driving potential = current
(Ch1 and Ch2) are light-gated cation channels obtained from the motile, single-cell
green algae
A gigaohm seal is pulled farther down with low Ca2+ conc. which breaks it away
from the membrane. Eq: Vm = -Vcmd
ANSWERS
Correct 121
Incorrect 00
1 of 121
Term
What happens as number of channel units increases?
Give this one a try later!
the diameter of the aq. pore
as external k increase injury potential
increases... so ion selectivity
decrease
decreases
the number of ion channels the size of the membrane increases...
decreases... so ion flow increases so ion permeability decreases
Don't know?
2 of 121
,Term
How are APs slightly different in sensory neurons?
Give this one a try later!
They are triggered only in sensory They are triggered in the dendrites
organs outside the nervous system. before reaching the cell body.
They are triggered farther along
a neuron before myleination They are triggered at the axon
begins on the axon (they are terminal after myelination.
pseduo-unipolar)
Don't know?
3 of 121
Definition
very selective neurotoxins label their corresponding channel proteins
using radioactive tags which can help purify a specific ion channel
from channel rich tissue. Purification can help us know the molecule's
size and gross chemical makeup. This is common for Na and K
channels.
Give this one a try later!
, How does an unequal distribution of Why does potassium contribute to
ions produce a resting Em? membrane pot but Cl doesnt?
How does toxin labeling and
What are the 3 families of channels
purification of a channel protein
and some examples?
work?
Don't know?
4 of 121
Term
What are the important features of Nicotinic Acetylcholine receptors
(nAChR)? (subunits, binding sites, selectivity)
Give this one a try later!
1. chemical excitatory
2. chemical inhibitory
3. electrical
Toxin labeling and purification of channel proteins & purification of mRNA coding
for desired channel proteins.
metabolic, structural, and energy requirements limit size. ex: jumbo squid has bigger
axons than larger giant squid. size doesnt mean bigger axons.
, nAChR has 5 subunits - 2 α, 1 β, 1 γ, 1 δ
There are two ACh binding sites, one on each of the α subunits. The outer
vestibule on extracell side of channel has a diameter of 20Å, but the channel
pore narrows down to 7Å at the selectivity filter in the transmemb
region.Cation selectivity due to negatively charged ring of aa residues in
transmemb region
-4 membrane spanning sequences
Don't know?
5 of 121
Term
What is PERMEABILITY?
Give this one a try later!
(P) refers to the ease with which ions can pass through an open membrane
channel. Open channel = permeability
(I) refers to the amount of actual ion movement through a channel under the
influence of a driving potential. Open channel + ions + driving potential = current
(Ch1 and Ch2) are light-gated cation channels obtained from the motile, single-cell
green algae
A gigaohm seal is pulled farther down with low Ca2+ conc. which breaks it away
from the membrane. Eq: Vm = -Vcmd
