What are the striated appearance of skeletal muscle fiber is mainly due to?

The striated appearance of skeletal muscle fibers is mainly due to the arrangement of thick and thin filaments within the muscle cells. These filaments are organized into repeating units called sarcomeres. The thick filaments are composed of the protein myosin, while the thin filaments are composed of the proteins actin and tropomyosin. The regular arrangement of these filaments gives skeletal muscle fibers their characteristic striated appearance.