Kingdom Monera - Flagella

Description:

Bacterial flagella are unistranded, equivalent to a single microtubular fibre. They are about 20nm in diameter and 1-7µm in length. Bacterial flagellum is made up of 3 parts - basal body, hook and filament.

Basal Body

• They are rod like and inserted into the cell envelope.
• Basal body bears ring like swellings in the region of plasma membrane and cell wall.
• Gram negative have L and P ring in the cell wall and S and M ring embedded in the cell membrane while gram positive bacteria bears only a single pair of rings i.e. S and M ring embedded in the cell membrane.

Hook

• Curved tubular structure which connects the filament with the basal body.
• They are the thickest part of flagellum.

Filament

• Long tubular structure.
• Causes turbulence in liquid medium.
• Made up of flagellin protein.