Question

In which part of the skeletal muscle excitation and contraction process do myosin heads firmly bind to actin?

a) Excitation Steps
b) Contraction Steps
c) Both Excitation and Contraction Steps
d) None of the above

Answer 1

In the skeletal muscle excitation and contraction process, myosin heads firmly bind to actin during contraction steps. During contraction, calcium ions bind to troponin, causing tropomyosin to move away from the binding sites on actin. This exposes the actin-binding sites, allowing myosin heads to bind to actin and form cross-bridges.

Step-by-step explanation:

In the skeletal muscle excitation and contraction process, myosin heads firmly bind to actin during contraction steps.

During contraction, calcium ions bind to troponin, causing tropomyosin to move away from the binding sites on actin. This exposes the actin-binding sites, allowing myosin heads to bind to actin and form cross-bridges.

The myosin then pulls the actin filaments towards the center of the sarcomere, resulting in muscle contraction.