Ion Channels+some Hemostasis bcs why not

Question 1

How many K ions are in the K channel at any given time, and in what position

Answer 1

2.

1-3 position/2-4 position (separated by water molecules)

Question 2

What is the role of kir6.2 and SUR1?

Answer 2

(ATP sensitive K channel subunits in pancreatic b cells)

ATP/ADP ratio increases -> ATP sensitive K channel shut down -> depol. -> insulin secretion

Question 3

Where does kir6.2+SUR localized in the body?

Answer 3

Pancreatic B cells

Question 4

Which technique reveals opening and closure of individual ion ch pores?

Answer 4

Patch clamp technique

Question 5

Define- open propability

Answer 5

Total time spent in open state divided by the total observation time

Question 6

Mutation in the kir6.2 SUR1 and symptoms (and treatment)

Answer 6

Persistent hyperinsulinemia hypoglycemia (PHHI)
As the name implies
We can treat with Diazoxide (helps open the channel)

Question 7

How does the Cl- channel pore stabilizes?

Answer 7

Helix dipole

Question 8

Requirements for activation of CFTR Cl- channel

Answer 8

Phosphorylation by cAMP dependent PKA (at least 10 serine residues in the regulatory domain)

Question 9

Drug that inhibits platelets activation?

Answer 9

Aspirin

Question 10

Mutation in Cl- channel will cause

Answer 10

Myotonia.
Unstable resting potential
Hyperactive muscle fiber

Question 11

What is the pro-coagulant effect of thrombin-TM complex?

Answer 11

Inhibits fibrinolysis by cleaving TAFI into its active form

Question 12

Where can we find Cl- channel 1 (Clc1)

Answer 12

Skeletal m

Question 13

Describe the gating mechanism of ATP sensitive K channel (activation by…. inhibition by….)

Answer 13

ATP inhibits (also Sulfonylurea)
ADP activates (also Diazoxide)

Question 14

Why does the Na ion excluded from the K channel?

Answer 14

Na is smaller than K -> Na coordination is energetically unfavorable

Question 15

ATP sensitive K channel SUR structure

Answer 15

3 TMD

2 intracellular NBD (Nucleotide Binding protein)

Question 16

How is the ATP sensitive K channel blocked while Depol.

Answer 16

By Mg ions from intracellular side

Question 17

How each K ion is stabilized in the K channel

Answer 17

Coordinated with 8 carbonyl oxygens (mimicking hydration shell)

Question 18

Triggers for platelet activation?

Answer 18

Thrombin
Collagen
PAF
Thrombaxane
ADP

Question 19

How does the CFTR pore closes?

Answer 19

NBD2 hydrolyses ATP -> dimer dissosiates

Question 20

What does the phosphorylated CFTR Cl channels need for gating?

Answer 20

ATP

Question 21

ATP sensitive K channel structure

Answer 21

Octamer built from
4 times Kir6.2
4 times SUR (Sulfonylurea Receptor)

Question 22

What is the throughput of K channel

Answer 22

1-2X10^8 ions/s

Question 23

Describe the structure of the K+ channel

Answer 23

Tetramer (each subunit contains 6TM helicels

P-loop btw. S5 and S6 (selectivity filter)

Question 24

What does COX enzyme produces?

Answer 24

1. Prostaglandins- pro inflammatory

2. Thrombaxane- promote clotting (aggregation of platelets)

Question 25

What is the role of kringle domain in the structure of tPA and plasminogen?

Answer 25

Lys binding

Question 26

What are the substrates of fVIIa?

Answer 26

fX
And
fIX

Question 27

CFTR structure

Answer 27

(ABC protein family)
Single polypeptide chain
-2 TMD 
-2 intracellular NBD
-Regulatory domain

Question 28

On what subunits subunit of ATP sensitive K channel does ATP acts on?

Answer 28

Kir6.2

Question 29

Structure of the Cl- channel (Clc)

Answer 29

Homodimer, both subunits individually form separated pores (two total)

Question 30

Who works on the SUR subunit? (ATP sensitive K channel)

Answer 30

ADP
Sulonylurea
k channel openers

Question 31

Define throughput rate

Answer 31

Number of ions transported through a channel in a given time

Question 32

Mutation in CFTR Cl- channel will cause

Answer 32

Cystic fibrosis (mucoviscidosis)

Question 33

What is the role of Cl- channel 1 (Clc1) in its tissue?

Answer 33

Tissue-skeletal m

Job- stabilizes resting memb potential

Question 34

What acts as voltage sensors on the voltage gated K ch?

Answer 34

Lys and Arg residues

Question 35

What is the active conf. Of CFTR?

Answer 35

NBD1-NBD2 heterodimer , 2xATP btw. them -> open pore

Question 36

Where does the ATP binds the CFTR?

Answer 36

2x ATP bounds the (2) NBD