Receptors Flashcards

1
Q

How many molecules of ACh bind to nAChRs? [1 mark[

A

2

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2
Q

Definition of potency [1 mark]

A

How much agonists are needed to produce an effect

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3
Q

Equivalent to potency [1 mark]

A

Threshold concetration

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4
Q

Definition of efficacy [1 mark]

A

Ability of an agonist to induce a biological effect

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5
Q

Definition of antagonists [1 mark]

A

Drugs that bind receptors without activating them

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6
Q

Structure of ligand gated ion channels [2 marks]

A
  • Pentamer

- Each protein has 4 transmembrane domains (hydrophobic)

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7
Q

How many antagonist binding sites are there in ligand gated ion channels? [1 mark]

A

2

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8
Q

What is the neuromuscular junction? [1 mark]

A

The synapse between a motor neurone and a skeletal muscle fibre

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9
Q

Muscle type nAChRs in proteins (in adults) [5 marks]

A
  • α1
  • ε
  • α1
  • β1
  • δ
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10
Q

What do foetal muscle type nAChRs have instead? [2 marks]

A

γ nAChR instead of ε nAChR

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11
Q

What does the body create antibodies for in Myaesthenia Gravia? [1 mark]

A

α1 subunit

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12
Q

Clinical sign of Myaesthenia Gravia [1 mark]

A

No miniature end-plate potentials (mepps)

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13
Q

Symptoms of Myaesthenia Gravia [5 marks]

A
  • Muscle weakness
  • Drooping eyelids
  • Fatigue
  • Difficulty swallowing or talking
  • Difficulty in exertion
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14
Q

Structure of G protein coupled receptors? [2 marks]

A
  • 1 protein (exception: insulin receptor)

- 7 transmembrane domains

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15
Q

Which G protein subunit does GDP bind to? [1 mark]

A

Alpha

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16
Q

What does alpha Gs do? [2 marks]

A
  • Activates adenylyl cyclase

- Increases [cAMP]

17
Q

What does alpha Gi do? [2 marks]

A
  • Inhibits adenylyl cyclase

- Decreases [cAMP]

18
Q

What does alpha Gq do? [2 marks]

A
  • Activates PLC

- Increase [Ca2+]

19
Q

What does the alpha subunit in the G protein have? [1 mark]

A

GTPase

20
Q

What happens to the affinity of alpha subunit to an enzyme that modulates a secondary messenger cascade when GTP is hydrolysed? [1 mark]

A

Affinity decreases

21
Q

What is the excitatory junction potential caused by? [1 mark]

A

The influx of Na+ and Ca2+ ions

22
Q

What is made from the hydrolysis of PIP2 by PLC? [2 marks]

A
  • Diacylglycerol (DAG) = interacts with lots of enzymes

- Inositol triphosphate (IP3) = releases Ca2+

23
Q

What recognises phosphotyrosines?

A

SH2 domains of other proteins

24
Q

What pathways are activated by the activation of tyrosine kinase receptors? [2 mark]

A
  • Ras

- PIP2

25
Q

What subunits of insulin is linked by disulphide bridges? [2 marks]

A
  • 2a

- 2b

26
Q

What does guanine nucleotide exchange factor (GEF) do? [2 marks]

A
  • Replaces GDP of Ras with GTP

- Makes exchange more efficient

27
Q

What binds to Ras when active? [1 mark]

A

Raf

28
Q

What does Jak phosphorylate? [2 marks]

A
  • Itself

- STAT (signal transducer and activator of transcription)

29
Q

What is smad-dependent signalling activated by? [1 mark]

A

TGF-β

30
Q

What does atropine block? [1 mark]

A

Muscarinic acetylcholine receptors