Actin

Question 1

How many domains in G actin

Answer 1

4

Question 2

What does G actin turn into

Answer 2

F actin

Question 3

What is the step size of actin

Answer 3

36nm

Question 4

What makes actin polar

Answer 4

ATP-binding cleft

Question 5

What ways do the arrows point

Answer 5

Always towards the negative end

Question 6

What does myosin S1 do

Answer 6

Form arrowheads and stabalize the actin

Question 7

What end does polymerization of actin occur preferentially at

Answer 7

The positive end

Question 8

What is the critical concentration of the negative end

Answer 8

0.60

Question 9

What is the crtical concentration of the positive end

Answer 9

0.12

Question 10

What happens if you are above or below CC

Answer 10

Above you are polymerizing and if you de polymerzing if below

Question 11

What if you have something in between the two numbers

Answer 11

Treadmilling

Question 12

What do you need for polymerization

Answer 12

G-actin bound to ATP

Question 13

What does Thymosin do

Answer 13

Sequesters actin and provides a reservoir

Question 14

What does profilin do

Answer 14

Promotes actin polymerization by changing G-ADP into G-ATP actin

Question 15

What is Cofilin

Answer 15

enhances depolymerization

Question 16

What does Cap z do

Answer 16

Will prevent assembly and disassembly binds to positive end

Question 17

What does Tropomodulin do

Answer 17

Binds to the negative end and prevents assebly and disassembly

Question 18

What does Cytochalasin do

Answer 18

Depolymerizes actin fillaments

Question 19

What does Phallodin do

Answer 19

Stabalizes actin filaments

Question 20

What are formins

Answer 20

Act as nucleating portiens and regulate assembly of unbranched filaments

Question 21

What end does formin regulate

Answer 21

Positive

Question 22

What regulates formin

Answer 22

RHO-GTP

Question 23

What does Arp 2/3 mediate

Answer 23

Filament branching

Question 24

What does Arp 2/3 need

Answer 24

Nucleation promoting factor such as wasp or wave that they have to be activated by Cdc24 and Rac

Question 25

What does WASp go with

Answer 25

Cdc42

Question 26

What does Wave go with

Answer 26

Rac

Question 27

What is listeria

Answer 27

It activates ARP 2/3 without Rac and moves arounf very quicky

Question 28

What can Arp 2/3 also do

Answer 28

Can end in endocytosis which is pulling the plasma membran into the cell and aid is phagocytosis which is pushing the membrane out

Question 29

What form bundels

Answer 29

Fimbrin and alpha actin (unbranched fillaments)

Question 30

What are networks

Answer 30

Spectrin and Filamin linked by other protiens

Question 31

What do Red blood cell depend on

Answer 31

Actin network binding protiens to support the cell membrane (ankyrin)

Question 32

What does ezrin do

Answer 32

Help the microvilli be stable by attaching to the membrane

Question 33

What does ankyrin do

Answer 33

Link and anchor the network to the membrane

Question 34

What does Dystrophin do

Answer 34

Pulls on the PM of the cell if the muscle cell is being pulled

Question 35

What is myosin

Answer 35

Actins motor protien have heavy and light chains atpase head beck binds light chain tail binds cargo

Question 36

Whatis class one of myosin

Answer 36

Works alone has one heavy chain support the PM tail attacheed to the membrane head to actin endocytosis

Question 37

What is class two of myosin

Answer 37

Found in muscle Organize themselves Heavy chains are in the middle and contract to the positive end

Question 38

What is class three of myosin

Answer 38

2 heavy chains organelle transport Membrane association/support contraction and transport positive end directed

Question 39

What effects the sliding speed

Answer 39

The length of the neck makes it go faster

Question 40

What is a single head step

Answer 40

72nm

Question 41

What happens when you add ATP

Answer 41

ADP is switched and the head lets go anc causes a recation

Question 42

Which end does the actin filament bind to

Answer 42

The positive end myosin is bound to

Question 43

What makes the head bind to the actin filament

Answer 43

When Atp is hydrolized

Question 44

What is the power stroke

Answer 44

Once it binds a Pi is released and elastic energy straightens myosin moving actin filament left

Question 45

What is the A band

Answer 45

Myosin 2 filaments they do not change size is is the thick fillament

Question 46

What comes closer together during contraction

Answer 46

Z disks

Question 47

What decreases in size

Answer 47

I band

Question 48

What is the I band

Answer 48

Is where the A band isn't

Question 49

Where is the actin found

Answer 49

Between the Z disks

Question 50

What happens to the A band when it is contracted

Answer 50

It stays the same

Question 51

What does the Z disks have

Answer 51

CapZ

Question 52

What extends from Z disk

Answer 52

Titin (like a spring that helps muscles strech and return back)

Question 53

What centers everything

Answer 53

Nebulin

Question 54

Where does Ca flood in muscle cells

Answer 54

The Sacroplasmic reticulum

Question 55

What opens up the Ca channels

Answer 55

An electric signal

Question 56

Why are there low levels of calcium

Answer 56

With phoshpate it makes a perciptate

Question 57

What does Ca do when it binds to.....

Answer 57

Troponin and tropomyosin shifts their actin filament exposing myosin binding sites