Which of the following terms refers to a bacterial cell having a single tuft of flagella at one end?
a. monotrichous b. amphitrichous c. peritrichous d. lophotrichous
The correct answer and explanation is:
The correct answer is d. lophotrichous.
Explanation:
In bacteriology, flagella are the hair-like appendages that enable bacteria to move. Bacteria can have different arrangements of flagella based on their location on the cell. The arrangement can be described using specific terms:
- Monotrichous: This term refers to a bacterium that has a single flagellum located at one end of the cell. It’s a simple, single flagellum, not a tuft or cluster.
- Amphitrichous: This arrangement involves a single flagellum at both ends of the bacterium. These bacteria have flagella at each pole of the cell, allowing movement in both directions.
- Peritrichous: This term describes bacteria that have flagella distributed all over the surface of the cell. These flagella can be spread uniformly or in clusters around the entire cell, enabling the bacterium to move in a more erratic, random direction.
- Lophotrichous: This refers to a bacterial cell that has a tuft or cluster of flagella at one end. The word “lophotrichous” comes from “lopho,” meaning tuft, and “trichous,” meaning hair or flagella. This type of flagellar arrangement allows for efficient movement in a single direction by concentrating flagella at one pole.
The lophotrichous arrangement is often seen in bacteria that require rapid and directed movement, such as in response to environmental stimuli. The tuft of flagella provides more propulsion than a single flagellum, giving the bacteria a “tail” that is more powerful for movement in a specific direction.
This flagellar arrangement can be crucial for bacteria in their ability to swim toward nutrients or away from harmful substances in their environment.