Which of the following statements about muscle contraction are true?

Question

(A) ATP hydrolysis releases myosin from actin.

(B) F-actin is a polymer of G-actin monomers and exhibits symmetry.

(C) ATP hydrolysis causes a conformational change in the myosin head.

(D) The heavy chain of the muscle form of myosin forms a coiled-coil structure with a globular head domain 

(E) Ca2+ binds to myosin and induces the interaction with actin, leading to filament sliding

I know C is one of the correct answer

Answer 1

Going through the other answer choices:

A is false - ATP binding releases actin from the myosin head, not its hydrolysis

B is debatable - F actin is a polymer of G actin, but the right handed helical structure is not perfectly symmetrical. It does exhibit some symmetry in the beta sheet locations, so I'd guess this is mostly correct.

C as you said is true, this conformational change leads to a weak interaction with the next F actin subunit

D is true - the 2 heavy chains of myosin each form the globular heads at the amino-terminus and continue into alpha-helices near their carboxy-terminus that coil around each other

E is false - in skeletal muscle, Ca2+ binds to troponin, whose conformational change uncovers the active site on actin that myosin can then bind to