Sliding Filament Theory

What are the repeating units called in myofibrils?

• Muscle fibers

• Sarcomeres

• Cylindrical structures

• Myofibrils

What does the sliding filament theory explain?

• How muscles contract at the molecular level

• How muscles grow in size

• How muscles generate heat

• How muscles store energy

The myosin heads bind to the exposed myosin-binding sites on ______, causing the actin filaments to slide over the myosin filaments in a power stroke.

ATP is required for the myosin heads to detach from actin, and myosin hydrolyzes ATP to ADP and Pi to return to its ______ position.

What triggers the release of calcium ions in muscle contraction?

• Action potential

• Troponin

• Tropomyosin

• Myosin-binding sites

The cross-bridge cycle repeats as long as _______ ions are available, resulting in the shortening of the sarcomere and muscle contraction.

Which two main protein filaments are involved in muscle contraction within each sarcomere?

• actin filaments and myosin filaments

• myosin filaments and troponin filaments

• actin filaments and troponin filaments

• actin filaments and tropomyosin filaments

Which is the Myosin?

Which is the Actin?

Which is the the Z-line?

Tags

NGSS.HS-LS1-4