Question

what does troponin bind to during excitation of muscle contraction?
○ sodium ions
○ adp
○ calcium ions
○ phosphate
○ atp

Explanation:

During muscle contraction excitation, troponin binds to calcium ions. This binding causes a conformational change in the troponin - tropomyosin complex, which exposes the myosin - binding sites on actin, allowing muscle contraction to occur.

Answer:

C. calcium ions