Signalling

Question 1

Signal transduction pathway (5 steps)

Answer 1

Release of primary messenger
Reception of primary messenger
Delivery of messenger inside cell by second messenger
Activation of effectors that alter physiological response
Termination of the signal

Question 2

What does GPCR stand for?

Answer 2

G-protein coupled receptors

Question 3

Most common mutation in cancer

Answer 3

Mutation in Ras

Question 4

What does GEF stand for?

Answer 4

GDP exchange factor

Question 5

What facilitates the change from GDP to GTP?

Answer 5

SOS (GEF) which binds to Ras

Question 6

What is the first messenger?

Answer 6

Extracellular signal that activates a receptor from the outside of the cell

Question 7

What is the second messenger?

Answer 7

low MW metabolite or inorganic ion that changes in concentration due to the effector enzyme

Question 8

Where is Glut 4 especially present?

Answer 8

In the cytoplasm

Question 9

Is there a high or low amount of second messengers during the resting state of the cell?

Answer 9

Low

Question 10

Common second messengers

Answer 10

Calcium ion
Diaclyglycerol
Cyclic GMP
Cyclic AMP
Inostiol 1,4,5-triohosphate (IP3)

Question 11

What activates the formation of cyclic nucleotides?

Answer 11

Adenylyl cyclase

Question 12

What deactivates the formation of cyclic nucleotides?

Answer 12

cAMP phosphodiesterases

Question 13

What does PI 3-kinase produce?

Answer 13

PIP3
Phosphorylates inositol (PIP2) in the 3rd position

Question 14

What kind of messenger is calcium?

Answer 14

Second messenger

Question 15

Is signal transduction specific?

Answer 15

Yes very specific

Question 16

What is the Ka when the affinity is high?

Answer 16

Low

Question 17

What is desensitisation?

Answer 17

When receptors are activated it triggers a feedback that shuts off the receptor or removes it from the cell surface

Question 18

What is divergence?

Answer 18

When a receptor activates two or more pathways

Question 19

What is G-protein activated by?

Answer 19

Binding of GTP

Question 20

What are the subunit of G protein?

Answer 20

Alpha
Beta
Gamma

Question 21

What is 7TM?

Answer 21

7 transmembranos receptor

Question 22

What does GTPase do?

Answer 22

Removes a phosphate making GTP GDP

Question 23

Does GEF favour GTP or GDP?

Answer 23

GTP

Question 24

Does GAP favour GTP or GDP?

Answer 24

GDP

Question 25

What are adrenergic receptors?

Answer 25

Protein receptor in the plasma tha bind epinephrine

Question 26

What is the target tissue of epinephrine?

Answer 26

Muscle Blood vessles

Question 27

What kind of stress is epinephrine in "charge" of? Long term or acute?

Answer 27

Acute stress

Question 28

What does cyclic AMP activate?

Answer 28

PKA

Question 29

What is an agonist?

Answer 29

A molecule that is different than the natural ligand but produces the same effect

Question 30

What is an antagonist?

Answer 30

Analog that binds the receptor and blocks the effects of the agonist and natural ligand

Question 31

Which subunit of PKA does cyclic AMP bind to?

Answer 31

Regulatory subunit

Question 32

2 subunits of PKA

Answer 32

Regulatory and inhibitor subunits

Question 33

What are kinases all phosphorylated by?

Answer 33

Ser and Thr (but specific ones, in a specific sequence (consensus sequences)

Question 34

What does CREB stand for?

Answer 34

cAMP Response element binding protein

Question 35

What does CREB do?

Answer 35

Alters the expression of specific genes regulated by cAMP

Question 36

What are Gi proteins?

Answer 36

Inhibitory G protein

Question 37

What does cholera toxin block?

Answer 37

GTPase activity of Gs

Question 38

Where is calcium stored?

Answer 38

In the ER

Question 39

What opens calcium channels?

Answer 39

IP3

Question 40

What is released when PIP2 is cut?

Answer 40

IP3 (polar end group)

Question 41

What does IP3 act as a second messenger to release?

Answer 41

Calcium

Question 42

What happens to Fura-2 when it binds to calcium?

Answer 42

It becomes florescent

Question 43

What is Fura-2 used to when bound to calcium?

Answer 43

Determine the intracellular calcium concentration as it is proportional to how fluorescent it is

Question 44

What is calmodulin?

Answer 44

An important calcium modulator Regulatory protein

Question 45

What 2 domains does receptor tyrosine kinases have?

Answer 45

Extracellular ligand binding domain Cytoplasmic Tyr kinase domain

Question 46

What does RTK stand for?

Answer 46

Receptor tyrosine kinases

Question 47

Why is Rat called a small G-protein?

Answer 47

Because it is not coupled to the receptor

Question 48

What kind of receptor is the insulin receptor?

Answer 48

Tyrosine kinase receptor

Question 49

Which subunits does insulin bind to in inulin receptors?

Answer 49

Alpha subunits

Question 50

What kind of dimers does Tyrosine kinase receptor have? and how many?

Answer 50

2 homodimers

Question 51

What is the SH2?

Answer 51

The modular protein domain that recognise phosphorylated tyrosine present in a specific consensus sequence

Question 52

What is PKB also called?

Answer 52

AKT

Question 53

Are the dimers of the EGF receptors always united?

Answer 53

No they have to go through dimerisation