Muscles and Movement Part 2

Question 1

what are microfillamentc composed of?

Answer 1

Actin

Question 2

Structure/growth

what is the two types actin?

Answer 2

Globular actin

Filamentous actin

Question 3

what is the effect of ATP binding to Gactin?`

Answer 3

higher affinity form dimers, therefore polymerizes to form f actin

Question 4

Where does hydrolyses occur adn what are its effects?

Answer 4

Hydrolyse ATP to ADT have less affinity cause shinkage

Question 5

What end does growth occur

Answer 5

+ end

Question 6

What is the effects of treadmilling

Answer 6

Growth adn shrinkage occur simultaneously

Question 7

Effects of capping protiens

Answer 7

Increase length by stabilizing
TROPAMODULIN - cap (-) end prevent dissociation
GAPZ- Bind to (+) end prevent polymerization

Question 8

Capping proteins involved in disassembly

Answer 8

\COFLIN - binds ADP actin

ARP - nucleate f action

Question 9

Capping proteins involved in Assembly

Answer 9

PROFLIN- binds to g-actin promotes assembly

Question 10

General arraignment of actin

Answer 10

+ end near the cell surface

Question 11

what is the motor protein of microfilaments?

Answer 11

myosin

Question 12

what is the monomer of actin

Answer 12

globular (G) actin

Question 13

what is the polymer of actin

Answer 13

filament (F) actin

Question 14

what is the critical concentration of +/- actin

Answer 14

the concentration of actin required for growth on either end

Question 15

arranges microfilaments in criss-cross pattern

Answer 15

fimbrin/fascin

Question 16

arranges microfilaments at 90 degree angle (tangled network)

Answer 16

filamen

Question 17

attaches microfilaments to membrane

Answer 17

dystrophin

Question 18

rodlike extensions of membrane

Answer 18

filopodia

Question 19

sheet like extensions of the membrane

ex. leukocytes or macrophages

Answer 19

lamellapodia

Question 20

which direction does myosin move (except myosin 6)

Answer 20

positive end

Question 21

how does myosin move along actin?

Answer 21

forms cross bridge (chemical reaction), releases, extends and power stroke (structural change utilizing ATP)

Question 22

what happens to myosin in the absence of ATP?

Answer 22

myosin cannot release/reattach to the actin, causes rigor mortis

Question 23

what are the steps of the sliding filament model?

Answer 23

1. ATP binds, causing myosin to dettach
2. myosin head extends and attaches to adjacent actin
3. release of phosphate promotes power stroke
4. ADP is released

Question 24

what does the distance of each cross bridge step depend on?

Answer 24

myosin neck length, binding sites on actin and helical shape of actin

Question 25

what are the step sizes of myosin movement?

Answer 25

hand over hand: 74nm

inchworm: 37nm