Question

Bacteria which have a tuft of flagella at one end are known as
A. Peritrichous
B. Monotrichous
C. Lophotrichous
D. Amphitrichous

Answer 1

Bacteria are microscopic organisms. They are single-celled organisms that exist in their millions, in every environment, both inside and outside other organisms. Bacteria are prokaryotes. They lack a nucleus and contain DNA that either floats freely in a twisted, thread-like mass.

Complete answer:
Flagella are defined as the microscopic hair-like structures involved in the locomotion of a cell. The word “flagellum” means “whip”.
The flagella have a whip-like appearance. It helps to propel a cell through the liquid. Some flagella are used in few organisms as sensory organs. It can sense changes in pH and temperature
On the number and placement of flagella on the cell, flagella are characterized into-
Monotrichous - In this, a single flagellum extends from one end of the cell. These are known as a polar flagellum. It can rotate clockwise and anti-clockwise. The clockwise movement moves the organism forward. The anti-clockwise movement pulls it backward. E.g.- Vibrio cholerae.
Amphitrichous - In this, a single flagellum or multiple flagella extend from two ends of the cell. These are also known as polar flagellum and can rotate clockwise and anti-clockwise.
Lophotrichous - In this, Tuft of flagella extends from one end or both ends of the cell. These are also known as polar flagellum and can rotate clockwise and anti-clockwise. e.g., Spirillum volutans.
Peritrichous - In this, Multiple flagella are randomly distributed over the entire bacterial cell. These are not polar flagella as they are found all over the organism. These flagella rotate anti-clockwise. They form a bundle that moves the organism in one direction. The organism does not move in any direction and begins tumbling if a flagella breaks and starts rotating clockwise. E.g. - E. coli.

Hence, the correct answer is option (C).

Note: Flagella are hair-like structures in an organism. Flagella have a whip-like appearance. These help a cell in locomotion. The lophotrichous flagella, the tuft of flagella extends from one end or both ends of the cell. These are called the polar flagellum. These can rotate clockwise and anti-clockwise. An example of bacteria having such flagella is Spirillum volutans.