13

Question 1

Common steps leading to changes in cellular response

Answer 1

• Chemical substance (drug, hormone, etc) travels from its source.
– e.g. ingested drug or toxin, endocrine hormone from a gland, neurotransmitter from a neuron, injected drug

• Chemical substance interacts with its target protein – this is called binding or reception* (this is where the proton receives the substance)

• The binding event affects the protein to either activate or inhibit it.

• This leads to functional consequences, that change the cellular response

Question 2

What is a receptor?

Answer 2

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

Question 3

How many individual receptor proteins are there?

Answer 3

1000

Question 4

What do receptors control?

Answer 4

Receptors control many important physiological processes,
including sight, smell & taste, heart rate, neurotransmission

Question 5

How many drugs activate or inhibit receptors

Answer 5

1/3

Question 6

Compare and contract enzymes and receptors

Answer 6

Enzymes:
• Generally one active site.
• Bind substrates.
• Change substrate into product.
• Can be membrane bound or free in cytosol

Receptors:
• Can have several binding sites.
• Bind ligands.
• Release ligand unchanged.
• Can be membrane bound or free in cytosol.

Both can be activated and inhibited, and used as drug targets.

Question 7

Three main classes of receptor

Answer 7

Question 8

Differences and similarities off receptor classes

Answer 8

• They have different structures
• The same overall steps of activation and inhibition occur
for all receptors, though the exact details differ.

Question 9

What is a ligand?

Answer 9

The general term given to a chemical substance that specifically binds to a receptor is a ligand.

Question 10

Ligands are very diverse in chemical structure,
ranging from small molecules to large peptides
and even proteins

Answer 10

Ligands are very diverse in chemical structure,
ranging from small molecules to large peptides
and even proteins

Question 11

Endogenous ligands

Answer 11

• produced in the body

Question 12

Exogenous Logan’s

Answer 12

Drugs and toxins

Question 13

All ligands make chemical contacts with their
specific receptors.

Answer 13

All ligands make chemical contacts with their
specific receptors.

Question 14

Where are recepotrs found?

Answer 14

Most receptors are found on the outer cell
membrane, where they act as sensors of the
extracellular environment

Question 15

Does Ligans pass through membrane?

Answer 15

Not usually

Question 16

The reception is a ____ of ______, controlling it from ______

Answer 16

The receptor is a “gate-keeper” of cellular
activity, controlling it from the cell surface.

Question 17

What are responses to extracellular rituals procured by

Answer 17

Intracellular responses to extracellular
signals can be produced by a membrane
receptor being activated

Question 18

There is _____ between Logan’s and receptors

Answer 18

Specificity

Question 19

Activation or inhibition will only happen whe.

Answer 19

Pairing is correct

Question 20

Specificity concept

Answer 20

Question 21

The process of binding to receptor proteins specifically is used to make…

Answer 21

Drugs that bind to only certain receptor targets

Question 22

What is an agonist

Answer 22

A chemical substance (ligand) that binds to a receptor and activates it is called an agonist.

Question 23

What happens for recepor activation

Answer 23

• receptor usually just sitting on membrane
• agonist binds - make enough chemical contracts to causes a conformational change
• allows to make an inside change even tho bound from outseides

Question 24

What is an antagonist

Answer 24

A chemical substance (ligand) that binds to a receptor and prevents activation by an agonist is called an antagonist
- stops agonist from bindinding - inhibiting cellular response
- signal trnaducting therfore doesn’t occur

LOTS OF EXOGENOUS DRUGS ARE ANTAGONISTS

Question 25

Comparing agonist and antogonist - NOT EXAMINABLE

Answer 25

• Both make specific chemical contacts with receptors • Often bind in a similar position but the chemical contacts
made by an agonist are sufficient to cause a conformational
change – both are keys for the same lock but only the
agonist can open it
- both are occupying same binding pocket in the same position
- chemical contacts make by against triggers conformational change unlike antagonist

Question 26

Activation and inhibition of proteins

Answer 26

Question 27

Inhibition of cellular response diagram

Answer 27

Question 28

Ligand, agonist and antagonist definitions

Answer 28

Question 29

Examples of signal transduction

Answer 29

Question 30

What happens after a conformational change has occurred and receptor is acitvated?

Answer 30

• active receptor starts a chain of events where messages are passed on through the cell via a process called signal transduction
• different receptors use different types of relay molecules to pass on messages

Question 31

How medical chemists produce safe and effective medicines

Answer 31

Medicinal chemists often start with the chemical structure of
an endogenous ligand, making new molecules from this to
produce safe and effective medicines.