lecture 13

Question 1

what are the 4 basic 4 steps in activation of receptor and describe them

Answer 1

chemical substance: Chemical substance travels from its source.
Bind receptor: Chemical substance interacts with its target protein – this is called binding or reception*
causes activation or inhibition in receptor: The binding event affects the protein to either activate or inhibit it.
Change cell response: This leads to functional consequences, that change the cellular response

Question 2

define receptor

Answer 2

A cellular protein (or assembly of proteins) that control chemical signalling between and within cells, this is called a receptor.

Question 3

3 differences between enzymes and ligans

Answer 3

Enzymes have generally one active site while receptors can have many.
Enzymes bind substrates while receptors bind ligands.
Enzymes change substrate into a product, receptors release the ligand unchanged.

Question 4

2 similarities between enzymes and ligands

Answer 4

Both types can be free in the cytosol or bound to the membrane.
Both can also be activated or inhibited and used as drug targets.

Question 5

define ligand

Answer 5

a molecule or drug that binds to a receptor, can be antagonist or agonist

Question 6

define agonist

Answer 6

a chemical capable of activating a receptor to induce a response

Question 7

define antagonist

Answer 7

something that binds and prevents the agonist from binding and inducing a response- prevents agonist action

Question 8

what are the three classes of receptor

Answer 8

ligand gated ion channel, receptor tyrosine kinase - RTK, G protein coupled receptor - GPCR

Question 9

what is endogenous and exogenous ligands

Answer 9

There are endogenous ligands that are
produced in the body.
* Drugs and toxins are examples of exogenous
ligands. as they are produced outside of the body

Question 10

what does the receptor being on the cell membrane mean

Answer 10

Receptors are usually found on the outer cell membrane where they act as sensors of the environment. Being on the outside means signals of environment can be sent into the cell without needing internal moevement of ligand or receptor. Ligands don’t usually pass through membranes.
Receptors contorl cell activity in a way.

Question 11

what fact about ligands and receptors is used when developing drugs

Answer 11

There is specificity between ligands and receptors.
* Activation or inhibition will happen only when this pairing is
correct.

Question 12

what does ligand specificity mean for binding drugs

Answer 12

This mechanism is used to make drugs that bind only to certain receptor targets.
* Medicinal chemists often start with the chemical structure of an endogenous ligand, making new molecules from this to produce safe and effective medicines

Question 13

whats an example of ligand drug and discuss it

Answer 13

Salbutamol can activate the same receptor as adrenaline and mimic its effects to cause bronchodilation because both ligands can make
similar chemical contacts with the receptor.

Question 14

what does a agonist do to the receptor and what does this cause

Answer 14

causes a conformational change to the receptor, which then causes signal transduction within the cell