Bacterial flagella are __________ .


a. anchored to the cell by a basal body
b. composed of hami
c. surrounded by an extension of the cytoplasmic membrane
d. composed of tubulin in hollow microtubules in a "9 + 2" arrangement

Verified step by step guidance

1. Understand the structure and function of bacterial flagella: Bacterial flagella are whip-like structures used for motility, allowing bacteria to move in their environment.
2. Recall the components of bacterial flagella: They consist of a filament made of flagellin protein, a hook, and a basal body that anchors the flagellum to the cell wall and membrane.
3. Evaluate each option based on bacterial flagella characteristics: Option (a) mentions anchoring by a basal body, which is true for bacterial flagella.
4. Consider the other options: (b) hami are different appendages found in some archaea, not bacteria; (c) bacterial flagella are not surrounded by an extension of the cytoplasmic membrane (that describes a different structure); (d) the '9 + 2' microtubule arrangement is characteristic of eukaryotic flagella, not bacterial ones.
5. Conclude that the correct description of bacterial flagella is that they are anchored to the cell by a basal body, matching option (a).

Key Concepts

Structure and Function of Bacterial Flagella

Bacterial flagella are long, whip-like appendages used for motility. They are primarily composed of the protein flagellin and are anchored to the cell membrane and cell wall by a basal body, which acts as a motor to rotate the flagellum and enable movement.

Difference Between Bacterial Flagella and Eukaryotic Flagella

Bacterial flagella differ from eukaryotic flagella in structure and composition. Unlike eukaryotic flagella, which have a '9 + 2' arrangement of microtubules made of tubulin, bacterial flagella are made of flagellin and lack this microtubule structure.

Hami and Their Role in Archaea

Hami are unique, grappling hook-like appendages found in some archaea, not bacteria. They are used for attachment rather than motility, distinguishing them from bacterial flagella, which are involved in movement.