Which of the following statements about prokaryotic flagellar structure is true?

• A. Flagella in prokaryotes are powered by ATP hydrolysis.
• B. The flagellar filament is made of tubulin.
• C. Prokaryotic flagella are surrounded by a membrane.
• D. The flagellum is composed of a filament, hook, and basal body.

Answer: (D)

Verified step by step guidance

1. Understand the basic structure of prokaryotic flagella, which typically consists of three main parts: the filament, the hook, and the basal body.
2. Recall that the filament is the long, whip-like structure that extends outside the cell and is primarily made of the protein flagellin, not tubulin.
3. Recognize that prokaryotic flagella are not surrounded by a membrane, unlike eukaryotic flagella which have a membrane sheath.
4. Know that the energy source for prokaryotic flagellar movement is the proton motive force (or sometimes sodium ion gradient), not ATP hydrolysis directly.
5. Conclude that the true statement is the one describing the flagellum as composed of a filament, hook, and basal body, which accurately reflects prokaryotic flagellar structure.