Flagella is the extension of cell membrane which passes through cell wall outside.....

Introduction:
Bacteria are single-celled organisms that exhibit various types of motility. One of the most common modes of bacterial motility is via flagella. Flagella are long, whip-like appendages that extend from the bacterial cell surface and enable the bacteria to move through their environment. However, the question arises as to whether flagella of bacteria arise from the cell wall or cell membrane.

Flagella of Bacteria:
Flagella are composed of protein subunits known as flagellin, arranged in a helical structure. The flagellum is anchored to the cell surface by a basal body, which is embedded in the cell envelope. The basal body consists of a series of rings that span the cell envelope, including the cytoplasmic membrane, the peptidoglycan layer (cell wall), and the outer membrane (in Gram-negative bacteria).

Flagella and Cell Envelope:
The question of whether flagella of bacteria arise from the cell wall or cell membrane is somewhat complicated by the fact that bacterial flagella are intimately associated with the cell envelope. In Gram-negative bacteria, the basal body of the flagellum passes through the outer membrane and peptidoglycan layer to contact the cytoplasmic membrane. In contrast, in Gram-positive bacteria, the basal body is embedded within the thick, multilayered peptidoglycan layer that constitutes the cell wall.

Conclusion:
Thus, it can be concluded that flagella of bacteria arise from both the cell wall and cell membrane, depending on the bacterial species and the type of flagellum. In Gram-negative bacteria, the basal body of the flagellum passes through the outer membrane and peptidoglycan layer to contact the cytoplasmic membrane, whereas in Gram-positive bacteria, the basal body is embedded within the thick, multilayered peptidoglycan layer that constitutes the cell wall.