Brainscape's Knowledge GenomeTM

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


See full index

Drugs > ELM 2 Ion Channels > Flashcards

ELM 2 Ion Channels Flashcards

1
Q

Q: What is gating in the context of ion channels?

A

A: Gating is the process by which the opening and closing of ion channels are controlled.

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

Q: What does voltage-gated mean for ion channels?

A

A: Voltage-gated refers to ion channels whose opening and closing are controlled by the membrane potential.

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

Q: What does ligand-gated mean for ion channels?

A

A: Ligand-gated refers to ion channels whose opening and closing are controlled by the binding of a ligand.

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

Q: What is the role of the alpha subunit in voltage-gated channels?

A

A: The alpha subunit is the main pore-forming subunit of voltage-gated channels.

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

Q: What is a pseudo subunit in voltage-gated Ca/Na channels?

A

A: A pseudo subunit is a structural component of the alpha subunit in voltage-gated Ca/Na channels, with each alpha subunit containing four pseudo subunits linked into a continuous peptide chain.

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

Q: What is the selectivity filter in an ion channel?

A

A: The selectivity filter is the part of the ion channel that determines which ions can pass through.

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

Q: What is selective permeability in ion channels?

A

A: Selective permeability is the tendency of ion channels to only allow certain ions to pass through.

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

Q: What is a voltage sensor in voltage-gated channels?

A

A: A voltage sensor is a charged structure, typically the fourth transmembrane domain of each subunit, that moves to open the channel’s gate in voltage-gated channels.

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

Q: How do molecules typically move across membranes?

A

A: Only lipid-soluble molecules can diffuse straight through, while others use proteins to cross membranes.

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

Q: What is the difference between carrier proteins and ion channels?

A

A: Carrier proteins do not form a continuous pathway through the membrane but instead bind the substrate on one side and flip it to the other side, whereas ion channels form a protein tube that allows ions to pass through continuously.

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

Q: What is the maximum rate of transport for carrier proteins?

A

A: The maximum rate of transport for carrier proteins is approximately 10,000 substrates per second.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Q: What is the maximum rate of transport for ion channels?

A

A: The maximum rate of transport for ion channels is approximately 1,000,000 ions per second.

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

Q: What are the properties common to all ion channels?

A

A: All ion channels are transmembrane proteins, selectively permeable, their opening is controlled, and they are diverse.

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

Q: What are some gating methods for ion channels?

A

A: Ion channels can be gated mechanically, by second messengers, phosphorylation, leak, ligand-binding, voltage changes, G-protein interactions, and temperature changes.

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

Q: What is the structure of a typical ion channel?

A

A: A typical ion channel has an extracellular funnel, a selectivity filter near the top with negatively charged residues, a central cavity, and an activation gate.

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

Q: How do ion channels distinguish between positive and negative charges?

A

A: Ion channels use rings of charge in the selectivity filter to repel ions of opposite charge types, allowing selective permeability.

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

Q: What is the basic structural unit of voltage-gated K+ channels?

A

A: Voltage-gated K+ channels are tetramers composed of four equivalent subunits.

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

Q: How many transmembrane domains does each subunit of a voltage-gated ion channel have?

A

A: Each subunit of a voltage-gated ion channel has six transmembrane domains.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Q: What forms the lining of the pore in voltage-gated ion channels?

A

A: The region between the 5th and 6th transmembrane domains forms the lining of the channel’s pore.

20
Q

Q: Which transmembrane domain acts as the voltage sensor in voltage-gated ion channels?

A

A: The fourth transmembrane domain acts as the voltage sensor.

21
Q

Q: From which evolutionary ancestor do all voltage-gated cation channels derive?

A

A: All voltage-gated cation channels are related and likely derive from a common prokaryotic ancestor.

22
Q

Q: How many genes are in the voltage-gated ion channel superfamily?

A

A: There are 143 genes in the voltage-gated ion channel superfamily.

23
Q

Q: How did Na+ and Ca2+ channels evolve from K+ channels?

A

A: Na+ and Ca2+ channels evolved from gene duplication of the Kv (K+ channel) gene.

24
Q

Q: Describe the structure of the alpha subunit in voltage-gated Na+ and Ca2+ channels.

A

A: The alpha subunit in voltage-gated Na+ and Ca2+ channels folds to form four pseudo subunits, creating the channel’s structure.

25
Q

Q: What is the function of the alpha-2 delta subunit in Ca2+ and Na+ channels?

A

A: The alpha-2 delta subunit stabilizes the channel’s structure and assists in its proper functioning.

26
Q

Q: How does the selectivity filter in ion channels work?

A

A: The selectivity filter has a ring of positive charges that repel negative ions and allows specific ions to pass through by stripping off their hydration shell and stabilizing them with oxygen atoms lining the channel.

27
Q

Q: What is the “knock on” mechanism in ion channels?

A

A: The “knock on” mechanism refers to the process where the entry of one ion into the channel pushes another ion through the channel, facilitated by the selectivity filter.

28
Q

Q: Why are Na+ channels able to open rapidly but inactivate after 1ms?

A

A: Na+ channels open rapidly due to voltage sensor movement and inactivate after 1ms because the inactivation gate blocks the channel.

29
Q

Q: Describe the translation process of Kv subunits.

A

A: Four copies of the Kv subunit are translated from mRNA and assemble to form a functional channel.

30
Q

Q: How do Na+ and Ca2+ channel alpha subunits fold to form a channel?

A

A: A single alpha subunit of Na+ or Ca2+ channels is translated from mRNA and folds into four pseudo subunits to form the channel.

31
Q

Q: Name the five main families of calcium channels based on their location and characteristics.

A

A: L type (CaV1.1-1.4), P/Q type (CaV2.1), N type (CaV2.2), R type (CaV2.3), and T type (CaV3.1-3.3).

32
Q

Q: Where are L-type calcium channels (CaV1.1-1.4) primarily located?

A

A: Heart, smooth muscle, CNS, retina, and cochlear hair cells.

33
Q

Q: Which calcium channel subtype is primarily found in neurons and associated with the Purkinje cells?

A

A: P/Q type (CaV2.1).

34
Q

Q: What is the primary location of N-type calcium channels (CaV2.2)?

A

A: Neurons.

35
Q

Q: What is the physiological role of R-type calcium channels (CaV2.3)?

A

A: They are found in neurons.

36
Q

Q: In which tissues are T-type calcium channels (CaV3.1-3.3) primarily found?

A

A: Neurons, heart, and smooth muscle.

37
Q

Q: What is the primary role of Na+ (Nav) channels in neurons and skeletal muscle?

A

A: They produce the excitatory phase of action potentials.

38
Q

Q: How do K+ (Kv) channels contribute to the action potential in neurons?

A

A: They help repolarize neurons and other cells during the second phase of an action potential and are involved in inhibitory responses to many neurotransmitters.

39
Q

Q: What is the role of Ca2+ (Cav) channels in cardiac muscle?

A

A: They are involved in the excitatory phase of action potentials.

40
Q

Q: Besides their role in action potentials, what other functions do Ca2+ channels have?

A

A: They help trigger vesicular release of neurotransmitters and couple electrical excitation of muscle to muscle contraction.

41
Q

Q: Which type of drugs are used to treat high blood pressure by targeting Ca2+ channels?

A

A: Calcium channel blockers.

42
Q

Q: How are local anesthetics and certain Ca2+ channel blockers used in pain management?

A

A: They are derived from marine snail toxin for pain resistant to morphine.

43
Q

Q: What types of ion channel blockers are used to treat heart rhythm disorders?

A

A: Ca2+, Na+, and K+ channel blockers.

44
Q

Q: Which ion channel blockers are used to treat angina?

A

A: Calcium channel blockers.

45
Q

Q: Give an example of a ligand-gated channel and its role in the autonomic nervous system (ANS).

A

A: The nicotinic acetylcholine receptor (nAChR) is fundamental to the operation of the ANS, relaying signals between pre-ganglionic and post-ganglionic neurons.

46
Q

Q: On what timescale do ligand-gated channels such as nAChRs operate?

A

A: Millisecond timescale.

Drugs (17 decks)

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