Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Meharry PHARM > Ion Channels I > Flashcards

Ion Channels I Flashcards

1
Q

where are ion channels located

A

on the membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the function of pore forming membrane proteins

A

They are pore-forming membrane proteins that establish and control the voltage gradient across the membrane by allowing the flow of ions down their electrochemical gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why are ion channels important

A

Without channels it is energetically unfavorable to move ions across a membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

T/F : The regulation of ion channels influences the life of the cell and its functions under normal and pathological conditions

A

The regulation of ion channels influences the life of the cell and its functions under normal and pathological conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Are ion channels pumps

A

no!! bc they do not require energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

T/F ion channels require ATP

A

FALSE!! they help ions move down their concentration gradient . Since they do not require ATP, they are not not considered pumps

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

T/F : Ions move through ion channels passively – down their concentration gradients

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

can ion channels move

A

no!! they are anchored to the cell membrane , specially the cytoskeleton and extracellular membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

T/F ion channels are present in almost every cell membrane

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the main difference between gated and non gated ion channels

A

non gated = non specific

gated - specific

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are the 3 types of gated ion channels

A
  1. voltage across the cell membrane
  2. ligand
  3. mechanical stimuli - heat and stretch
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is the typical molecular weight of an ion channel

A

Molecular weights range from 25-250 kD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

T/F : Ion channels are integral membrane glycoproteins

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

T/F : Ion Channels usually consist of 2 or more subunits

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the 2 distinct states for ion channels

A

open - CONDUCTING

closed - NON CONDUCTING

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does it mean for an ion channel to be in an inactivated state

A

some channels have also inactivated state (open but nonconducting)
- Part of the channel structure or external particle blocks otherwise open channel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is responsible for the opening and closing of the pore

A

Conformational changes in channel protein are responsible for opening and closing of the pore

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what are the 2 gating theories

A

Two gating theories –

  1. Ball and chain
  2. Paddle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

If no confirmational change takes place in ion channel will the ion channel open

A

no

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

channels are made up of ….

A

subunits

21
Q

Ion channels are made from 2-6 similar proteins or homologous structural units called _____ _____ _____- they associate creating the functional ion channel

A

Ion channels are made from 2-6 similar proteins or homologous structural units - PORE-FORMING SUBUNITS - they associate creating the functional ion channel

22
Q

how many types of ion channels are there and what are their names

A

Basically, two types (on the basis of the mechanisms controlling their gating):

  1. Voltage-gated
  2. Ligand-gated
23
Q

how are voltage gated ion channels opened

A

Activated by changes in voltage gradient across the plasma membrane

24
Q

how are ligand gated ion channels opened

A

Activated by binding of ligands to the channel

25
Q

can some ion channels have both voltage gated and ligand gated areas

A

yurp

26
Q

give 3 examples of voltage gated channels

A

Sodiumchannels
• Potassiumchannels •
Calciumchannels

27
Q

How would you automatically know that the following are ligand gated:

Nicotinic Acetylcholine receptor
• GABA receptor
• Glycine receptor
• Glutamate receptor

A

BECAUSE THEY ARE CHEMICALS!!!

28
Q

Name the ion channel type: opens in response to the change in membrane potential

A

voltage gated

29
Q

Name the ion channel type: opens in response to a specific extracellular signal

A

ligand gated

30
Q

Name the ion channel type: opens or closes in response to a specific intracellular molecule

A

signal gated

31
Q

Name the ion channel type: opens in response to a change in membrane stretch

A

stretch gated

32
Q

What is an ionotropic receptor

A

Binding of ligand (neurotransmitter) to receptors directly open the channel which is an integral part of the receptor complex

33
Q

What is a metabotropic receptor

A

Binding of ligand (neurotransmitter) to receptors does not result in the direct gating of a channel rather engages a G protein, which results in the production of a second messengers that modulate voltage-gated channels (generally calcium and potassium channels)

34
Q

Will inotropic or metabotropic cause a direct opening of a channel

A

inotropic

35
Q

Are inotropic or metabotropic associated with GPCR’s

A

ionotropic

36
Q

where are ligand gated channels typically located

A

Typically, these are ion channels located on the postsynaptic (receiving) side of the neuron

37
Q

what Promotes fusion of synaptic vesicles with the presynaptic membranes

A

Calcium

38
Q

what is the function of ligand gated channels in synapse

A

Ligand gated channels are responsible for
changing a chemical signal in the synapse (neurotransmitter) to either an excitatory or inhibitory post synaptic potential

39
Q

Action Potential ____ voltage gated _____ channels

Trigger ____ of Ca2+

Ca2+ cause _____ of synaptic
vesicular membranes, and ____neurotransmitter (nt)

Ligand-gated ion channels
_____——-results changes in
postsynaptic potential

A

Action Potential opens voltage gated Ca2+ channels

Trigger entry of Ca2+

Ca2+ cause fusion of synaptic
vesicular membranes

Ligand-gated ion channels
open——-results changes in
postsynaptic potential

40
Q

T/F : Nerve transmission of the Action Potential involves BOTH voltage gated
ion channels and ligand gated ion channels

A

TRUE: Nerve transmission of the Action Potential involves BOTH voltage gated
ion channels and ligand gated ion channels

41
Q

The resting (closed) ion channel when binds to _______ makes the excited / open state. Longer exposure leads to ______ and channel closure.

A

The resting (closed) ion channel when binds to (acetylcholine (ACh) makes the excited (open) state. Longer exposure leads to desensitization and channel closure.

42
Q

Why does a K+-selective channel not allow Na+ ions through?

A

Channels have a specialized region that acts as a molecular sieve called The SELECTIVITY FILTER

43
Q

NMDA receptors are an example of

A

voltage and ligand gated channels

44
Q

Explain how NMDA receptors work

A

(a) Glutamate alone causes the channel to open, but at the resting membrane potential, the pore becomes blocked by Mg2+ ions
(b) Depolarization of the membrane removes the Mg2+ block and allows Na+ and Ca2+ to enter

45
Q

What are the 4 components in voltage gated channels

A

Selectivity filter
Voltage sensor
Activation Gate
InactivationGate

46
Q

What are the 3 components of ligand gated channels

A

Selectivity filter
Ligand binding site(s)
Desensitization Gate

47
Q

a drug is given that causes blockage of cAMP synthesis . What will happen if a ligand binds to the GPCR

A

no effect because cAMP is blocked

48
Q

Drug A binds to GPCR what do you expect ….cAMP will be synthesized .

Drug given that causes inhibition of cAMP synthesis or hydrolysis

A

huh

49
Q

T/F neuortoxin target ion channels

A

true , can be fast acting and deadly

Meharry PHARM (24 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions