Question

During cross-bridge formation, the cocked head of myosin attaches to what on the thin filament?

Answer 1

Myosin head attaches to actin molecules of thin filament during cross bridge formation.

Explanation:

The tropomyosin covers the sites on the actin filament when a person is having rest.

However during some physical activity, the muscles contract. And for the onset of this contraction, `Ca^(2+)` ions bind to one of troponin (three polypeptide comlpex of thin filament) molecules. As a result, the troponin molecules moves slightly. This movement displaces tropomyosin and exposes the binding sites of the molecules in actin chain for the myosin head. Thus myosin head attaches to the binding sites on actin molecules and cross-bridges are formed.

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