Intro to receptors & signal transduction pathways Flashcards

1
Q

What is signal transduction?

A

The process whereby information is transmitted inside of the cell

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2
Q

Receptor proteins bind “signals” i.e. drugs and endogenous ligands with ______ affinity

A

high

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3
Q

conformational changes in the structure of the receptor protein then convert the extracellular chemical signal into one or more _________ signals

A

intra-cellular

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4
Q

What are the three naturally occurring chemical messengers?

A

Hormones
Neurotransmitters
Local chemical mediators

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5
Q

What is an agonist drugs?

A

A type of drug that binds to and exerts an affect on a receptor.

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6
Q

All agonists are full agonists. True or false?

A

False - some drugs can be partial agonists

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7
Q

What is an antagonist drug?

A

A type of drug which also binds to a receptor but which does not alter the activity of the receptor, it simply prevents the agonist from binding

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8
Q

All antagonists are competitive. True or false?

A

False - some are non-competitive

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9
Q

What are the two main groups of receptor proteins?

A
Plasma membrane (extracellular) transmembrane receptors 
Cytosolic/nuclear (intracellular) receptors
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10
Q

Water soluble drugs are unable to diffuse across membranes. How are they able to exert their effects?

A

By binding to plasma membrane receptor proteins on the surface of cells

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11
Q

How do lipid soluble drugs such as propofol and steroid hormones such as oestriol exert their effects?

A

Pass through lipid bilayer and bind to intracellular (cytosolic) receptors

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12
Q

What are the three families of plasma membrane receptors?

A
Ligand gated ion channels 
G-protein coupled (GPC) receptors
Tyrosine Kinase (TK) receptors
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13
Q

What is the generalised structure of plasma membranes composed of?

A

extracellular domain
transmembrane domain
intracellular (cytosolic) domain

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14
Q

How many subunits does the nicotinic acetylcholine receptor have?

A

5

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15
Q

GPC receptors have a membrane-spanning domain consisting of ___________

A

7 transmembrane helices

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16
Q

Which type of receptor mediates many biological functions e.g. smell, taste, exocytosis?

A

GPC receptors

17
Q

GPC receptors are coupled to a ____ protein

A

GTP

18
Q

Signal transduction involves the movement of a G-protein to an ________

A

effector site

19
Q

What are the stages that result in the activation of a GPC receptor?

A

ligand binds to receptor
the receptor is activated as a result
the activation of receptor activates G protein that is coupled to it
G protein goes and activates something else at effector site - often but not always adenylate cyclase
Increased conc of cyclic AMP
activated effectors

20
Q

GPC receptors are coupled to a GTP protein. True or false?

A

True

21
Q

There is only one family of cytosolic receptors. What is it?

A

Nuclear hormone (steroid) receptors

22
Q

How are nuclear hormone (steroid) receptors characterised?

A

Presence of ligand binding domain and a DNA binding domain

23
Q

How do ligands of nuclear hormone receptors exert their effect?

A

Cause the receptor to translocate to the nucleus, where the receptor binds to DNA and acts as a transcriptional regulator

24
Q

Cytosolic receptors regulate gene expression. True or false?

A

True