Yes, a myofibril is composed of actin and myosin filaments, which are the fundamental proteins responsible for muscle contraction.
Structure of a myofibril:
- Myofibrils are long, cylindrical structures found inside muscle cells (muscle fibers)
- They are made up of repeating units called sarcomeres
Types of filaments:
- Actin (Thin Filaments):
- Made of protein actin
- Attached to Z-lines
- Responsible for sliding during contraction
- Myosin (Thick Filaments):
- Made of protein myosin
- Contains cross-bridges (heads) that interact with actin
How they work:
- During muscle contraction, actin slides over myosin
- This shortens the sarcomere and causes the muscle to contract
Key Takeaway:
A myofibril consists of actin (thin) and myosin (thick) filaments, which work together to enable muscle contraction.