Question

A bacteria with single flagella on opposite ends is called-----
A. Peritrichous
B. Amphitrichous
C. Lophotrichous
D. None of the above.

Answer 1

Hint: Bacteria is a single-celled organism. It lacks the membrane-bound organelles. It is small and microscopic. The genetic material they contain is DNA. Bacteria are the only organisms which contain prokaryotic types of cells.

Complete answer:
Flagella in the case of bacteria are used in the locomotion. Flagella is a hairlike structure. It is the characteristic feature of the protozoan group. It also occurs in the gametes of algae, fungi, mosses, slime molds, and animal sperms. The number and position of flagella vary from organisms to organisms. In the case of bacteria, the flagella are made up of a protein called flagellin. The energy for the movement of flagella is provided by the ATP. In the case of bacteria, most of them do not possess the flagella hence they are called the non- motile. The main function of flagella in bacteria includes a role in pathogenesis in the case of E.coli. They also help in the identification of bacteria. Their most important function is locomotion.
> Peritrichous- It means the flagella are present in the periphery of the organism. They have the flagella all over the surface. Example- E. coli, Salmonella enterica.
> Amphitrichous- In this type one flagella comes from two ends. There will be the presence of two flagella. They are present in the opposite direction. Example- Alkaligens faecalis.
> Lophotrichous- A tuft of flagella is present on one or both sides of bacteria. Example- Spirillum

A bacteria with single flagella on opposite ends is called Amphitrichous. So, the correct answer is option B.

Note:
Amphitrichous bacteria contain two flagella on either side. The other type of bacteria with flagella include:
Monotrichous- they have a single polar flagellum. Example- Vibrio cholerae
Atrichous bacteria – they lack the flagellum. Example- Lactobacillus.