learning outcomes

Question 1

Describe the basic functions of receptors

Answer 1

1. Enable specificity
2. Allows specific response to be carried out:
   - ionotrophic receptors- alter the permeability of membranes
   - JAK kinases- alter protein synthesis
   - enzymatic receptors- affects proliferation and differentiation
   - G- protein receptors and second messenger model

Question 2

what is meant by receptor?

Answer 2

proteins which recognise a specific molecule and compound. Binding of such compound will lead to inhibition or activation of a certain metabolic pathway.

Question 3

explain the terms agonist and antagonist

Answer 3

Agonist- drug which mimics action of receptor.

Antagonist- drug which blocks action of receptor

Question 4

Describe relationship between agonist concentration and effect

Answer 4

As the concentration of the agonist increases the effect of the receptor will increase until it becomes completely saturated.

Question 5

Define the term affinity

Answer 5

Defines the strength of attraction between the drug and the receptor. High affinity- EC50=half maximal response

Question 6

define efficacy

Answer 6

Defines how well the drug activates the receptor

Question 7

Process of transmembrane signalling

Answer 7

Ionotrophic, JAK kinases and enzymatic.
G-protein receptors:
1- Camp- G-subunit binds adenyl cyclase which activates Camp. Camp stimulates protein phosphorylation by activating Kinases
2- Phospholipase-C - G-subunit binds to phospholipase C which activates IP3 and DAH. DAH activates kinases, IP3 leads to release of Ca2+

Question 8

sources of intracellular calcium

Answer 8

• Release from ER by IP3
• From outside of cell through ligand-gated channels
• Blocking transport of calcium out of cell