cross bridge cycling

Question 1

step 1

Answer 1

relaxed sacromere

Question 2

step 2

Answer 2

Ca2+ is released by the sarcoplasmic reticulum

Question 3

step 3

Answer 3

Ca2+ binds to tropnin

Question 4

step 4

Answer 4

the binding of Ca2+ causes tropnin to change shape and roll tropomyosin off the myosin binding sites (ON)

Question 5

step 5

Answer 5

the myosin head cocks forming a cross bridge between the myosin head and the myosin bonding site (GRAB)

Question 6

step 6

Answer 6

myosin pulls actin towards the m-line which makes the power stroke where ATP is hydrolized to ATP-TPI (PULL)

Question 7

step 7

Answer 7

ATP binds to myosin allowing it to break the cross bridge steps 4-6 repeat as long as Ca2+ and ATP are present (release)