A tuft of flagella present at one or both ends of bacterial cell is known as:
**Core Concept**
The presence of tufts of flagella at one or both ends of a bacterial cell is a characteristic feature of certain bacterial species. This arrangement is often associated with motility and is a result of the bacterial cell's evolutionary adaptation to its environment.
**Why the Correct Answer is Right**
Flagella are whip-like structures that provide motility to bacteria. The arrangement of flagella at one or both ends of the bacterial cell is known as a "lateral flagellum" or "monotrichous" arrangement, respectively. In monotrichous bacteria, a single flagellum is present at one end of the cell, while in lateral flagellum bacteria, multiple flagella are present at the sides of the cell. This arrangement allows the bacteria to move efficiently through their environment. The presence of flagella is mediated by the flagellin protein, which is encoded by the flg gene.
**Why Each Wrong Option is Incorrect**
* **Option A:** This is not a valid term related to flagella or bacterial motility.
* **Option B:** This option is incorrect as it does not describe the correct arrangement of flagella.
* **Option D:** This option is incorrect as it does not accurately describe the presence of flagella at one or both ends of the bacterial cell.
**Clinical Pearl / High-Yield Fact**
Bacteria with flagella are typically motile, while those without are non-motile. This characteristic can be used to differentiate between various bacterial species in the laboratory.
**Correct Answer:** C.