Question

During muscular contraction, the myosin head binds to the exposed active sites on actin to form a

• A. Motor unit
• B. Cross arm
• C. Cross bridge
• D. Motor-end plate

Answer 1

The correct option is C Cross bridge

(C) Cross bridge:



Sliding filament theory:

According to sliding filament theory, thin filaments called actin filaments slide over myosin filaments (thick filaments). The myosin head binds to the exposed active sites on actin forming a cross bridge. This process utilises ATP. When the myosin head binds and pulls at the actin filament, the latter comes closer to the M-line (centre of A band).
The cycle involves a sequence of events involving the thick and thin filaments of a muscle that result in muscle contraction.

Final answer: (C) Cross bridge