Function of Ca+2 (Exam 2)

Question 0

A conformational change occurs in the actin

Answer 0

The troponin and tropomyosin shift and expose the binding site for myosin

Question 1

The AP travels across the sarcolemma and runs down the T Tubule

Answer 1

Causing Ca+2 to be released from the lateral sacs

The Ca+2 then binds to the TnC of troponin

Question 2

Myosin heads are now able to alternately bind and detach from actin

Answer 2

The hinge region of the myosin pulls the actin filaments toward the center of the sarcomere

Question 3

Siding filament theory

Answer 3

Actin slides toward the center of the sarcomere
Distance between the Z-disc is reduced
The I bands shorten
The H zone disappears
A bands move closer together

Question 4

The release of energy from the splitting of ATP (at the myosin ATPase binding site)

Answer 4

Powers the sliding filament theory

Question 5

The shortening of the sarcomere via actin and myosin attachment/detachment will continue

Answer 5

As long as Ca+2 is in the sarcomere allowing myosins binding site to be exposed

Question 6

For relaxation to take place

Answer 6

Ca+2 must be removed form the sarcomere

Question 7

Located on the surface of the SR

Answer 7

Is a Ca+2 ATPase pump

Question 8

Ca+2 ATPase pump

Answer 8

Using energy gained from splitting ATP it pumps Ca+2 out of the sarcomere and back into the lateral sacs

Troponin and tropomyosin recover myosins binding site
Actin and myosin are no longer attached and relaxation occurs (sarcomere lengthens back out)