Question

Sliding filament theory can be best explained as

• A. When myofilaments slide past each other actin filaments shorten while myosin filament do not shorten.
• B. Actin myosin filaments shorten and slide past each other.
• C. Actin and myosin filaments do not shorten, but rather slide past each other.
• D. When myofilament slide past each other myosin filament shorten while actin filament do not shorten.

Answer 1

The correct option is C Actin and myosin filaments do not shorten, but rather slide past each other.

The sliding filament theory is the explanation for how muscles contract to produce force. The actin and myosin filaments within the sarcomeres of muscle fibres bind to create cross-bridges and slide past one another, creating a contraction.

During muscle contraction, the thin actin filaments slide over the thick myosin filament. When Calcium is present the blocked active site of the actin clears. Power stroke: myosin head pivots pulling the actin filament toward the center.

The cross bridge detaches when a new ATP binds with the myosin.

So, the appropriate answer is 'Actin and myosin filaments do not shorten, but rather slide past each other.'