Question

The motile bacteria are able to move by :

• A. Fimbriae
• B. Cilia
• C. Pili
• D. Flagella

Answer 1

The correct option is D Flagella

Many bacteria move using a structure called a flagellum. The flagellum is a long, spiral-like appendage that protrudes from the surface of the bacterium and can extend for a distance longer than the bacterial cell itself. It is responsible for motility.

Fimbriae are long filamentous polymeric protein structures located at the surface of bacterial cells. They enable the bacteria to bind to specific receptor structures and thereby to colonise specific surfaces.

Cilia are small hair-like protuberances on the outside of eukaryotic cells. They are primarily responsible for locomotion, either of the cell itself or of fluids on the cell surface.

Pili are proteinaceous, filamentous polymeric organelles expressed on the surface of bacteria. Sex pili allows exchange of DNA in baceteria, while some pili are meant for attachment and some classes of pili help in movement. But all the classes of pili does not allow motility to the bacterial cell.

Hence, the correct answer is flagella.