Receptors

Question 1

What is a ligand?

Answer 1

-any molecule that binds to a receptor
-may be agonist or antagonist

Question 2

What is an agonist?

Answer 2

Anything that binds to a receptor, initiating a response

Question 3

What are endogenous agonists?

Answer 3

Chemical mediators found within the body that bind to a receptor producing a response

Question 4

What are the 2 types of chemical communication + cell signalling?

Answer 4

Convergence and divergence

Question 5

What is convergence chemical chemical communication?

Answer 5

-all cells express multiple types of receptors so single cells can integrate information

Question 6

What does having multiple receptors on the same cell allow for?

Answer 6

Allows it to take in lots of different types of information and integrate them to produce one response

Question 7

What is divergence chemical communication?

Answer 7

Most extracellular signal molecules can act on more than one type of cell

Question 8

What does the same receptor being expressed by more than one type of cell allow for?

Answer 8

Allows for a coordinated response involving multiple organs

Question 9

What are receptors?

Answer 9

-macromolecular proteins that serve as recognition sites
-refers to any protein of a cell that can bind to a molecule which then modulates some activity of the cell

Question 10

What are receptors made up of?

Answer 10

Subunits - parts are antagonists

Question 11

What do receptors within the same class share?

Answer 11

Common structural features

Question 12

What features do the 3 classes of receptor found on the cell plasma membrane share

Answer 12

-have transmembrane-spanning segments
-possess a ligand binding domain
-ligands are hydrophilic so can’t cross the cell membrane

Question 13

What is a ligand binding domain?

Answer 13

An area of a receptor where a ligand can bind - usually extracellular

Question 14

What are 4 classes of receptors?

Answer 14

-ligand gated ion channels (ionotropic receptors)
-G protein coupled receptors (metabotropic receptors)
-kinase linked receptors
-nuclear (cytoplasmic, intracellular receptors)

Question 15

What are the chemical mediators for ligand-gated ion channels?

Answer 15

Most small molecule chemical mediators

Question 16

How fast is the response when using ligand-gated ion channels?

Answer 16

-very rapid response (miliseconds)
-response has small duration

Question 17

How do ligand-gated ion channels work?

Answer 17

-agonist binds, causing channel to open
-channel closes when agonist is removed or receptor enters a desensitised state

Question 18

What are the chemical mediators for G protein coupled receptors?

Answer 18

-peptide hormones
-most small molecule chemical mediators

Question 19

How fast is the response from G protein coupled receptors?

Answer 19

-quite fast response (seconds)
-response lasts longer than ion channels

Question 20

What are G protein coupled receptors formed from?

Answer 20

A singular transmembrane protein made up of 7 domains

Question 21

What are the chemical mediators for kinase-linked receptors?

Answer 21

-peptide hormones
-cytokines

Question 22

How fast is the response from kinase-linked receptors?

Answer 22

-long response (hours)
-response lasts long time (hours or days)

Question 23

What are the chemical mediators for nuclear receptors?

Answer 23

Steroid hormones

Question 24

What does transduction mechanism and type of intracellular signal effect?

Answer 24

-type of response
-speed of response
-duration of response