Section 7

Question 1

How do hydrophobic and hydrophilic cell signals differ?

Answer 1

Hydrophobic: works on intracellular receptors, carried thru blood
Hydrophillic: works on cell surface (plasma membrane)

Question 2

How are both hydrophobic and hydrophilic cell signals alike?

Answer 2

Induce gene transcription and cell signal must eventually terminate (transient); final destination is at the nucleus

Question 3

What is an endocrine signal?

Answer 3

Signal is carried via blood

Question 4

What is a paracrine signal?

Answer 4

Signal is sent from one cell to an adjacent cell

Question 5

What is an autocrine signal?

Answer 5

Signals itself

Question 6

What are the three major kinase receptors?

Answer 6

1. Tyrosine-kinase
2. JAK-STAT
3. Serine-Threonine kinase

Question 7

What are the features of tyrosine-kinase receptors?

Answer 7

1. Majority of growth factor receptors
2. Needs ATP
3. Dimerization
4. Activates proteins kinase

Question 8

What site do 50% of drugs target?

Answer 8

G-Protein Coupled Heptahelical Receptor

Question 9

What activates G-Protein couple heptahelical receptor?

Answer 9

cAMP, IP3, DAG

Question 10

What is the third messenger in G-Protein Coupled Heptahelical Receptor?

Answer 10

Calcium

Question 11

What are the actions of G-Protein?

Answer 11

1. Bind GDP in inactive state, GTP in active state
2. Activate/Inhibit adenylate cyclase
3. Contain GTPase activity

Question 12

How does G-Protein get terminated?

Answer 12

1. Degrade cAMP to AMP
2. Trade GTP for GDP
3. Internalize receptor
4. Remove phosphate (phosphatases)

Question 13

What is the phosphate donor in the plasma membrane receptors?

Answer 13

ATP

Question 14

What is the phosphate acceptor in the plasma membrane receptors?

Answer 14

Tyrosine, Serine, Theronine (all have -OH groups)

Question 15

What is the target of IP3?

Answer 15

Calcium channel

Question 16

What is the target of DAG?

Answer 16

Protein Kinase C

Question 17

What is typically a 3rd messenger?

Answer 17

Ca++