Question

Bacteria having a tuft of flagella at both ends are called
A. Peritrichous
B. Bitrichous
C. Amphitrichous
D. Atrichous

Answer 1

Hint: Bacteria are included in prokaryotes. These are unicellular and microorganisms. The bacterial cell is very much different from a eukaryotic cell. Bacteria are mostly non-motile but sometimes they move through flagella and show beating type movement. Flagella are made by microtubules and microtubules are made by tubulin protein.

Complete answer: Bacteria having a tuft of flagella at both ends are called amphitrichous. The flagella found in bacteria have a diameter of 140-185 A and a length of 4.5 micrometres. The flagellum is attached by a hook with the cell membrane and the hook is attached with the basal body. The basal body is also called blepharoplasty. The bacterial flagellum has three parts that are basal granule, hook, and filament. Flagella are found in only some type of bacteria. If it is absent bacteria is called atrichous. If only one flagellum is found in bacteria at one end it is called monotrichous. E.g. Vibrio cholerae. If a group of the flagellum is found at an end it is called lophotrichous. E.g. Spirillum volutans. If flagella are found on the whole-cell of bacterium it is called peritrichous. E.g. E coli. Lastly, if flagellum or flagella is/are present at both ends of bacteria it is called amphitrichous. E.g. Nitrosomonas.
Hence, the correct answer is option C.

Note: Flagellum was first of all observed by Engleman. Flagella are found at the external side of the cell but their origin is internal. Flagellum can be of two types: whiplash flagellum, in which lateral trichomes are absent and tinsel flagellum, in which trichomes are found. Flagella and cilia both are similar structurally. In bacteria, only one flagellum is found and cilia are absent. Cilia are found in protozoan and other multicellular organisms. Both are made by microtubules.