Question

The structural explanation of how a muscle fiber contracts is called the

thin filament theory.

myosin spiral theory.

active site rule.

sliding filament theory.

cross-bridge connection.

Answer 1

The sliding filament theory explains how muscle fibers contract by the interaction between myosin and actin filaments.

Step-by-step explanation:

The most widely accepted theory explaining how muscle fibers contract is called the sliding filament theory. According to this theory, myosin filaments use energy from ATP to "walk" along the actin filaments with their cross bridges. This pulls the actin filaments closer together. The movement of the actin filaments also pulls the Z lines closer together, thus shortening the sarcomere.