A sarcomere is the basic structural and functional unit of a muscle fiber. It is the segment between two Z-discs, which anchor the thin actin filaments. Sarcomeres are responsible for muscle contraction, as they shorten when the myosin filaments pull on the actin filaments during the contraction process. Each sarcomere contains alternating bands of thick and thin filaments, giving skeletal muscle its striated appearance. The arrangement of these filaments allows for efficient force generation and movement. Sarcomeres work together in a series to enable the overall contraction of a muscle, contributing to various physical activities.