Question

fill in the blank question

in a myofibril, the blank filaments stabilize the thick filaments and prevent over-stretching.

Explanation:

Identify the structural components of a myofibril

In skeletal muscle fibers, myofibrils are composed of three main types of myofilaments:

1. Thick Filaments: Made primarily of the protein myosin.
2. Thin Filaments: Made primarily of the protein actin, along with tropomyosin and troponin.
3. Elastic Filaments: Made of the giant accessory protein called titin (also known as connectin).

Determine the function of elastic filaments

The question asks for the specific filaments that stabilize the thick filaments and prevent over-stretching.

• Elastic Filaments (composed of titin) run through the core of each thick filament and anchor it to the Z disc and M line.
• Their primary functions are to keep the thick filaments centered between the thin filaments, provide passive elastic recoil during muscle relaxation, and prevent the sarcomere from over-stretching by resisting excessive extension.
• Therefore, the correct term to fill in the blank is "elastic".

Answer:

In a myofibril, the <blank>elastic</blank> filaments stabilize the thick filaments and prevent over-stretching.