lecture 13 - protein activation & inhibition 1 Flashcards

1
Q

What are some common compounds that may inhibit or activate proteins?

A

hormones, neurotransmitters, drugs, toxins, poisons

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2
Q

What are the common steps in protein activation or inhibition?

A

Substance travels from source, binds to protein, activation/inhibition, changes to cellular response due to functional change

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3
Q

What are protein receptors?

A

Cellular proteins that control chemical signalling between and within cells

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4
Q

What is the difference between enzymes and receptors in terms of active sites?

A

Enzymes generally have 1, while receptors can have several

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5
Q

What is the difference between enzymes and receptors in terms of what they bind?

A

Enzymes bind substrates while receptors bind ligands

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6
Q

What is the difference between enzymes and receptors in terms of release of the bound substance?

A

Enzymes change substrate into product, while receptors release ligands unchanged

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7
Q

Where are receptors and enzymes found in a cell?

A

Membrane bound or free in cytosol

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8
Q

What are the 3 main classes of receptor?

A

Ligand-gated ion channels, G Protein Coupled Receptors (GPCR), Receptor tyrosine Kinase (RTK)

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9
Q

What is the name for a chemical that binds to a receptor?

A

A ligand

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10
Q

Where are endogenous ligands produced?

A

Inside the body

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11
Q

Where are exogenous ligands produced?

A

Outside the body, e.g. drugs and toxins

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12
Q

What are the 3 types of receptor signalling used by locally-produced chemical substances?

A

Synaptic, paracrine, autocrine

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13
Q

What type of receptor signalling is used by chemical substances produced at a distant site to the receptor (i.e. hormones)?

A

Endocrine

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14
Q

What is synaptic signalling?

A

The presynaptic cell produces a chemical that is received by a specific post-synaptic cell that expresses the receptor

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15
Q

What is paracrine signalling?

A

A cell produces a chemical that is received by receptors on a number of neighbouring cells

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16
Q

What is autocrine signalling?

A

A cell excretes a chemical that is received by receptors expressed on the same cell

17
Q

What is endocrine signalling?

A

A cell produces a chemical, it is transported via the blood stream, and is received by a distant cell expressing the appropriate receptor

18
Q

Where are the majority of receptors found, and why?

A

The outer cell membrane, so they can act as sensors of the extracellular environment without the ligands having to pass into the cell

19
Q

What is ligand specificity?

A

Receptors and ligands have specificity, so only certain ligands match the corresponding receptor’s binding pocket

20
Q

What is the name for a ligand that is able to bind to and activate a receptor?

A

An agonist

21
Q

How do agonists activate receptors?

A

They bind, the receptors undergoes a conformational change

22
Q

What happens when a membrane receptor has been a activated by an agonist ligand?

A

Active receptor starts a chain of events where messengers are passed on thorough the cell via signal transduction

23
Q

What is the name for a ligand that binds to a receptors and prevents activation by an agonist?

A

Antagonist

24
Q

What is an antagonist ligand?

A

A ligand that binds to a receptor and blocks agonist binding to inhibit signal transduction

25
What is the signal transduction mechanism of adrenaline in the lungs?
Adrenaline acts as an agonist to activate the B-adrenergic receptor (GPCR), resulting in signal transduction that causes bronchodilation
26
What is the signal transduction mechanism of insulin?
Insulin acts as an agonist to activate an insulin receptor (a RTK), resulting in signal transduction and then glucose uptake
27
What receptor does adrenaline act on to cause bronchodilation?
beta-adrenergic (a GPCR)
28
What type of receptor is beta-adrenergic
GPCR
29
What receptor does insulin act on to increase glucose uptake?
Insulin receptor
30
What type of receptor is an insulin receptor?
RTK receptor