Question

The condition of having a single flagellum at one end of a bacterium is
A) Peritrichous
B) Amphitrichous
C) Lophotrichous
D) Monotrichous

Answer 1

Hint: Flagellum or flagella is a hair-like structure that primarily uses as an organ of locomotion in the cells of many living organisms. Flagella are mainly found in the protozoan group Mastigophora and are also present in the gametes of algae, fungi, mosses, slime molds, and animals.

Complete step-by-step answer:
The flagellum is primarily responsible for the locomotion of that cell. It also often acts as an organ of sensory as it is sensitive to chemicals and temperatures outside the cell.
Four different types of the organism can be observed according to the position and number of the flagella which are monotrichous, peritrichous, lophotrichous, and amphitrichous.
In the case of monotrichous, a single flagellum is present at one end. This flagellum is called a polar flagellum which is able to rotate clockwise and anti-clockwise. In the case of peritrichous, several numbers of flagella are present all over the organism. As they are present all over the organism therefore, they are not polar flagella.
When several numbers of flagella are present at one end of the organism, this type of organism is called lophotrichous. These flagella are the polar flagellum which are able to move clockwise and anti-clockwise. Like the monotrichous, the clockwise rotation of flagellum moves the organism forward and the anti-clockwise rotation moves in reverse.
If a single flagellum is present on both the ends of the organism, then it is amphitrichous. The flagellum is also known as a polar flagellum. In the amphitrichous, flagellum can rotate clockwise and anti-clockwise and the clockwise rotation takes the organism forward while the anti-clockwise rotation takes in reverse.

Therefore, the correct option is option D.

Additional Information: A flagellum or flagella in the plural is a lash-like accessory organ that stretches from the body of cells of some bacteria and eukaryotic cells are known as flagellates. The structure of the flagellum is composed of flagellin protein which the structure of flagella is divided into three parts and that is the basal body, hook, and filament. A flagellate can hold one or more flagellums.

Note: The flagellum is a microscopic structure whose appearance is hair-like. It is involved in the locomotion of a cell. The flagella helps a cell to step through the liquid. There are some special flagella that are used as sensory organs that can detect the changes in pH and temperature. According to the position and number of the flagellum, organisms are four types; monotrichous, peritrichous, lophotrichous, and amphitrichous. Monotrichous is the type of bacterium which has a single flagellum at one end.