Muscle Contraction

Question 1

how many molecules of ATP are used for one powerstroke

Answer 1

1

Question 2

what is the size of one powerstroke

Answer 2

10 nm

Question 3

what happens to the sarcomere during contraction

Answer 3

myosin cross-bridges attach to actin, exert force on them to move= actin filaments slide into the middle of the sarcomere= muscle contraction

Question 4

during contraction do the actual filaments change in length

Answer 4

NO

Question 5

what affects the number of myosin crossbridges that interact with actin

Answer 5

the amount of overlap between the thick and thin filaments

Question 6

why do small movements in each sarcomere cause a bigger overall length change in the sarcomere

Answer 6

because the sarcomeres are connected in series

Question 7

describe the role of the ATPase cycle contraction

Answer 7

ATP is hydrolysed into ADP+ Pi
causes myosin head to attach to actin
this forms a cross-bridge
a power-stroke is triggered = allows myosin to pull the actin towards the M-line and away from the Z-line, thereby shortening the sarcomere
myosin remains attached to actin until a new ATP molecule binds.