Question

value: 20

atp is required for attachment of myosin head.

true
false

Explanation:

Analyze the role of ATP in myosin binding

In muscle contraction, the binding of actin and myosin to form a cross-bridge does not require ATP. Instead, the myosin head binds to actin spontaneously once the binding sites on actin are exposed by calcium ions.

Identify the actual role of ATP

ATP is required for the detachment of the myosin head from the actin filament. When a new ATP molecule binds to the myosin head, it causes the myosin to release its grip on actin. Additionally, the hydrolysis of this ATP into ADP and inorganic phosphate (\(\text{P}_i\)) provides the energy to "cock" the myosin head back into its high-energy state, preparing it for the next power stroke.

Evaluate the statement

The statement in the question asserts: "ATP is required for attachment of myosin head." Since ATP is actually required for the detachment (dissociation) of the myosin head rather than its initial attachment, this statement is false.

Answer:

• True
• False (Correct answer)