Pharmacology 1

Question 1

Why don’t receptors all bind the same signalling molecules?

Answer 1

Allows the cells to specialise, so they don’t all perform the same function

Question 2

Different receptors can be activated by

Answer 2

Different and sometimes even the same signalling molecule

Question 3

What type of response can a receptor evoke?

Answer 3

Membrane permeability
Metabolism
Secretory activity
Rate of proliferation or differentiation
contractile activity
The process is called signal transduction

Question 4

What type of chemical messenger binds to an intracellular receptor?

Answer 4

A lipid soluble receptor, steroid hormones

Question 5

Where are the receptors found that can influence the transcription of DNA?

Answer 5

Within the nucleus

Question 6

What response can steroids have on transcription?

Answer 6

They are a transcription factor and can alter the rate of transcription

Question 7

Where is the receptor for the chemical messenger for the chemical messenger NO (nitric oxide)

Answer 7

Within the cell as NO is lipophilic

Question 8

How many different types of cell surface receptors exist?

Answer 8

4

Question 9

Describe the 4 different types of cell surface receptors

Answer 9

Ionotropic- receptor channel- The receptor is also an ion channel
Receptor that functions as an enzyme - Receptor enzyme
Receptor that directly affects an enzymes activity-Integrin receptor
G-Protein coupled receptors

Question 10

What are the tyrosine kinase receptor enzymes involved in?

Answer 10

Proliferation and differentiation

Question 11

What does a G protein coupled receptor look like?

Answer 11

7 transmembrane spanning sements

Question 12

What happens to a subunit of a G protein when the G protein coupled receptor is activated?

Answer 12

It regulates an enzyme that produces a secondary messenger, e.g
Regulates adenyl cyclase, which in turn produces the second messenger cAMP (cyclic AMP), This in turn regulates the activity of another enzyme, PKA (protein kinase A) which then goes off to phosphorylate proteins

Question 13

Give the possible effects of a secondary messenger

Answer 13

Make channels open wider
Regulate protein synthesis
Regulate the release of calcium
Regulate the synthesis of RNA in the nucleus
Might act on microtubules making things secrete things out of the cell

Question 14

What happens when phospholipase C is regulated?

Answer 14

Two secondary messengers are regulated, these (diacylglycerol and Inisitol triphosphate) - These are responsible for activation of Protein Kinase C and the release of calcium ions from internal stores

Question 15

What effect can G proteins have on ion channels?

Answer 15

They can evoke a slow EPSP/ Slow IPSP

Question 16

What are the sources of calcium ions?

Answer 16

Internal stores via inisitol triphosphate
From outside the cell via ligand or voltage gated channels
Via inhibition of calcium transport out the cell

Question 17

What are the effects of calcium in the cell?

Answer 17

Can regulate the activity of the target protein e.g of Protein Kinase C
Can bind to calmodulin which directly activates a target protein
Works via some other calcium binding protein e.g troponin

Question 18

Give examples of receptors with intrinsic enzyme activity

Answer 18

Tyrosine kinases
Receptor guanylyl cyclases - retina

Question 19

What type of enzyme can receptors interact with directly?

Answer 19

JAK kinases

Question 20

What are JAK kinases involved in?

Answer 20

Protein synthesis

Question 21

What is the result of activation of Adenylyl cyclase by a G protein?

Answer 21

Makes cAMP (secpndary messenger) which activates a protein kinase