Spirillum is not classified as a spirochete because spirochetes
a. do not cause disease.
b. possess axial filaments.
c. possess flagella.
d. are prokaryotes.
e. none of the above

Verified step by step guidance

1. Understand the characteristics of Spirillum and spirochetes.
2. Identify the unique features of spirochetes that differentiate them from other bacteria.
3. Recall that spirochetes are known for their distinctive movement mechanism.
4. Consider the structural components that enable spirochetes' movement.
5. Determine which option correctly describes a feature that is unique to spirochetes and not shared with Spirillum.

Key Concepts

Spirochetes

Spirochetes are a unique group of bacteria characterized by their spiral shape and flexible cell wall. They are distinguished by the presence of axial filaments, which are specialized structures that allow them to move in a corkscrew motion. This motility is crucial for their ability to invade host tissues and can be associated with various diseases, such as Lyme disease and syphilis.

Flagella

Flagella are long, whip-like appendages that enable bacterial motility. They are composed of a protein called flagellin and can be found in various arrangements on bacterial cells. While both spirochetes and other bacteria can possess flagella, the presence of axial filaments is a defining feature that differentiates spirochetes from other spiral-shaped bacteria like Spirillum.

Prokaryotes

Prokaryotes are single-celled organisms that lack a nucleus and membrane-bound organelles. This group includes bacteria and archaea, which are characterized by their simple cell structure. Understanding that both spirochetes and Spirillum are prokaryotes helps clarify their classification, but it is their specific structural features, such as axial filaments in spirochetes, that ultimately differentiate them.