Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

BIOM 3090 > Lec 2 > Flashcards

Lec 2 Flashcards

1
Q

What are major functions of physiological receptors? (2) VIA what domains?

A
  • Ligand binding (VIA ligand binding domain)
  • Message propagation (VIA effector domain)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How do drugs modify cellular function after binding to receptors? (4)

A
  • Initiate
  • Enhance
  • Diminish
  • Terminate (Block)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the signal transduction pathway? (AKA receptor- effector coupling mechanism) (3)

A

the receptor, its cellular target, and any intermediary molecules

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

What are the major types of drug receptors? (4)

A
  • transmembrane ion channels
  • transmembran G-protein coupled
  • transmembrane enzymatic cytosolic domain coupled
  • intracellular
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the membrane lipid bilayer impermeable to?

A

Polar (charged) anions and cations (Na+, K+, Ca2+, Cl-)

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

What do ion channels have key roles in?(4)

A
  • neurotransmission
  • cardiac conduction
  • smooth and skeletal muscle contraction
  • secretion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How are ion channels classified? (3)

A
  • Architecture (subunits)
  • Ions conducted through the channel
  • mechanism of activation (Ligand and voltage activated channels are major drug targets)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Where are ligand activated (gated) channels found?

A

In the CNS
- Excitatory NTs (ACh or glutamate)
- inhibitory NTs (glycine or GABA)

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

What are characteristics of nicotinic acetylcholine receptor ()

A
  • ligand gated channel
  • isoforms found in skeletal muscle and neurons
  • has 5 subunits in skeletal muscle
  • closed state is occluded by bulky amino acids side chains
  • open is when ACh binds to alpha unit
  • Na+ is major electrolyte passed K+ also passed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How many subunits do ligand gated channels have?

A

5

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

What causes for ligand gated channel to be closed?

A

bulky amino acid side chains

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

How does ligand gated channel open?

A

Binding of 2 molecules of ACh to alpha subunit

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

What is the major electrolyte passed in ligand gated channels? what else is passed?

A

Na+, K+

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

What are voltage-activated channel types? (4)

A

Na+, K+, Ca2+, Cl-

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

Where do voltage activated Na+ channels initiate action potentials?

A

Axons of nerves and muscles

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

Can drugs have greater affinity for certain conformations?

A

Yes, like state-dependent (local anaesthetics and antiarrythmics)

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

What is a local anesthetic example and how it works?

A

Lidocaine binds to the channel to prolong the refractory period

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

What is the refractory period?

A

Inactive channel

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

What is the polarized period?

A

Reset and opening of channel

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

What are some intracellular molecule activated ion channel characteristics?

A

Sulfonylurea receptor (SUR1)
- regulated ATP dependent K+ channel in pancreatic beta cells
- sulfonylurea class oral hypoglycemics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the most abundant class of receptors in the body?

A

G-protein coupled receptors (GPCRs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How many GPCRs do humans express?

A

over 800

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are GPCRs for? (~2)

A
  • over half are dedicated to sensory perception (sight, smell, taste)
  • the rest are for nerve activity tension in smooth muscle, metabolism, force and rate of cardiac contraction and secretion of most glands.
24
Q

How are GPCRs activated?

A

By neurotransmitters (ACh, NE), eicosanoids (PGs), peptide hormones, opioids and others

25
What receptors do over half of all non antibiotic drugs act?
GPCRs
26
What do GPCRs bind to?
G proteins
27
How are signals from G proteins terminated?
Hydrolysis of GTP to GDP by inherent GTP-ase activity on alpha subunit
28
Major role for G proteins
Activate effector molecules that produce second messengers
29
How are effectors characterized (4)
- Adenylyl cyclase - gyanylyl cyclase - phospholipase C - various ion channels
30
What are the best known G proteins
G alpha
31
What is the lesser known G protein?
Beta gamma subunit isoforms role - can regulate K+ and Ca2+ channels
32
What are beta adrenergic receptor group characteristics
Important - catecholamines (EPI NOREPI)- endogenous ligands- stimulate cAMP and cellular effects
33
What are key G protein mediated second messengers? (4)
-cGMP -IP3 -cAMP -DAG
34
What are some transmembrane receptors with intracellular linked enzymatic domain characteristics? (SHORTEN THIS)
- important in metabolism, growth and differentiation, tonic activation can cause tumours - have single membrane spanning proteins compared to seven (G-protein receptors) - receptors form dimers or multi subunit complexes for transduction of signals - activity if receptors = adding/removing phosphate groups from specific aa's (phosphorylation can cause change in energy and shape)
35
What are receptor tyrosine kinase characteristics? (SHORTEN THIS)
- largest group of this receptor class - endogenous ligands (insulin) - effectors include SH2 domains on other signalling molecules like Grb2 - drugs (Imatinib - TK inhibitor) - anticancer agent
36
What modifies nuclear hormone events?
circulating steroid hormones are lipophilic diffusing through the plasma membrane to bind transcription factors
37
What do receptors process? (2)
ligand binding domain and a DNA binding domain
38
What do nuclear events depend on?
which co-activators or co-repressors of gene transcription are recruited
39
Is gene transcription fast or slow? are they long lasting?
SLOW - min to hrs but they're long lasting
40
What is lag on in gene transcription?
Slow onset of cellular effects
41
What is lag off in gene transcription?
slow onset of cellular effects
42
What is an example of gene transcription in nuclear hormone receptors?
Glucocorticoids
43
What is NO gas?
Labile gas produced locally - important in the CV system - binds to N-terminal domain of soluble GC and enhances activation of cGMP
44
What is the endothelial NO?
eNOS
45
What is the inducible NO?
iNOS
46
What is the neuronal NO
nNOS
47
what are vascular smooth muscle effects of cGMP?
cGMP acting on PKG - vasodilation from reduced intracellular calcium levels (Angina pectoris and nitrovasodilators)
48
Can drug receptors exist outside of the plasma? why?
yes, for communication purposes
49
Examples of drug receptors found outside of the plasma are... (2)
- vasoconstriction (ACE inhibitors) - Neurotransmitters (Acetylcholinesterase inhibitors)
50
Why do some drug receptors have a cell surface adhesion function ?
to allow cell-cell interaction for various functions (inflammation, coagulation) (eptifibatide an antagonist of the platelet GPIIb-IIIa receptor)
51
What is an example of a drug receptor that provides a structural role for the cell?
Antineoplastics - Microtubule inhibitors (paclitaxel for cancer therapy)
52
How do cells integrate multiple signals to produce a coherent cellular response?
Signalling convergence by second messengers can generate coordinated net cellular effects
53
Is the magnitude of a cellular response to a ligand lesser than the initiating stimulus?
No, greater than
54
Can cells amplify the effects of receptor binding by ligands (Epinephrine / adrenaline)
YES !
55
Why can drug-induced activation or inhibition of a receptor have long lasting effects on subsequent responsiveness to drug binding?
It prevents overstimulating of the pathway and cellular damage

BIOM 3090 (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions