Call Signaling

Question 1

How are signals transduced through cells? (Steps)

Answer 1

Stimulus- signaling molecule - receptor - 2nd messanger - response

Question 2

Define a stimulus

Answer 2

Virtually any change in the environment

Question 3

What might modulate a cells response to a signal? ( 4 things)

Answer 3

1. Concentration of ligand (signal molecule)
2. Available receptors
3. Presence of antagonists
4. Affinity of receptor for ligand

Question 4

Where can receptors be located?

Answer 4

1. Membrane ( water soluble ligands)
   2.Intracellular

Question 5

What are two characteristics of intracellular receptors?

Answer 5

1. no second messangers
2. will move into nucleus and bind to DNA and affect transcription

Question 6

What two forms of response are there depending on what receptor was activated?

Answer 6

1. Altered function of existing proteins (by water soluble ligands)
2. Altered protein synthesis (Lipophilic ligands)

Question 7

What are the 3 types of membrane receptors?

Answer 7

1. G coupled
2. Channels
3. enzyme linked

Question 8

Describe the pathway of an activated G-coupled receptor

Answer 8

Ligand binds w/ receptor - receptor activates g-protein - g protein activates second messanger pathway - cAMP ( protein kinase A) and phospholipase C which then activates IP3 (Ca dependant protein kinase) and DAG (protein kinase C)