In biology, a filament is a 'long chain of proteins, such as those found in hair, muscle, or in flagella'. They are often bundled together for strength and rigidity. Some cellular examples include: In biology, a filament is a 'long chain of proteins, such as those found in hair, muscle, or in flagella'. They are often bundled together for strength and rigidity. Some cellular examples include: Filaments are also highly dynamic in nature and far from a static structure that acts as a stable 'scaffold' for a cell. Some phenomena that profile a protein filaments' dynamics are: