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Concept

Bacterial flagella

Rotary appendages for motility

fluh-JEL-uh

structuremotilityh-antigenchemotaxis

High-yield clue

Flagella provide motility and their flagellin protein is the H antigen used in serotyping.

Overview

Long helical protein filaments driven by a rotary motor that propel bacteria and enable directed movement (chemotaxis) toward or away from stimuli. Their protein (flagellin) is the basis of the H antigen used in serotyping.

Classification

  • Helical protein filament
  • Rotary basal-body motor
  • Flagellin subunits
  • Arrangement patterns vary

Lab & identification clues

  • H (flagellar) antigen vocabulary
  • Monotrichous/peritrichous arrangement concept
  • Motility-test interpretation vocabulary

Associations

  • Chemotaxis toward nutrients
  • Swarming motility vocabulary
  • Serotyping by H antigen

Commonly confused with

  • Pili/fimbriae
  • Axial filament (spirochete)

Frequently asked questions

What is Bacterial flagella?

Long helical protein filaments driven by a rotary motor that propel bacteria and enable directed movement (chemotaxis) toward or away from stimuli. Their protein (flagellin) is the basis of the H antigen used in serotyping.

What is the high-yield clue for Bacterial flagella?

Flagella provide motility and their flagellin protein is the H antigen used in serotyping.

What is Bacterial flagella associated with?

Bacterial flagella is associated with Chemotaxis toward nutrients, Swarming motility vocabulary, and Serotyping by H antigen.

What is Bacterial flagella commonly confused with?

Bacterial flagella is commonly confused with Pili/fimbriae and Axial filament (spirochete).

Original microbiology concept summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC/WHO topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment selection, infection-control instructions, or specimen-handling guidance.

OpenStax: Microbiology 2e concept foundations - sourceNCBI Bookshelf: Medical Microbiology general concepts - sourceCDC: CDC public-health concept pages - source