Question

which structure do the calcium ions bind to when muscle contraction is initiated? multiple choice the actin myofilament the troponin molecule the tropomyosin molecule the sarcoplasmic reticulum the telomere

Explanation:

When muscle contraction is initiated, calcium ions bind to troponin. Troponin is a complex of three proteins that regulate muscle contraction by controlling the interaction between actin and myosin. Binding of calcium to troponin causes a conformational change that exposes the binding sites on actin for myosin, leading to muscle contraction.

Answer:

The troponin molecule