Modulation of cell signaling

Question 1

example of amplification

Answer 1

One beta 1 - adrenergic receptor may activate many Gs.

Each Gs may stimulate many adenylyl cyclases to result in formation of 10,000 cAMP molecules

One cAMP molecule may activate one PKA to phosphoryalte 100 proteins to increase their activity

Question 2

Agonist Potency

Answer 2

due to both

• high affinity
• high ability to signal and elicit a response

Question 3

Efficacy

Answer 3

from maximal obtainable response

Question 4

Full Agonist

Answer 4

reaches highest efficacy

Question 5

partial agonist

Answer 5

reaches lower efficacy than the full agonist

Question 6

Competitive Antagonism

Answer 6

• bind to receptor and compete with agonist

- shifts concentration-response graph toward right

Question 7

agonist

Answer 7

• bind to receptor

- signal and elicit a response

Question 8

antagonist

Answer 8

-bind to receptor but do not signal to elicit a response

Question 9

T/F: Inhibition by competitive antagonists is surmountable by agonist

Answer 9

True

Question 10

Non-competitive antagonism

Answer 10

• does not bind to the same receptor site, but affects how it binds
• NOT surmountable by the agonist

Question 11

Cooperativity

Answer 11

• All or Nothing Responses
• Uses two or more agonist molecules
• more partners needed, the steeper the curve

Question 12

ligand

Answer 12

substance which binds to a receptor

Question 13

agonist

Answer 13

substance which binds to a receptor and activates the cell signaling mechanism

Question 14

EC50

Answer 14

concentraion of agonist, which causes a half-maximal effect

Question 15

potency

Answer 15

ranking of agonists according to the EC50

Question 16

efficacy

Answer 16

ranking of agonist according to magnitude of maximal effect

Question 17

Attenuation

Answer 17

• integral part of signaling

- necessary to prevent uncontrolled signaling