Flagella

(noun. /fluh-JEH-luh/)  Singular: Flagellum

by Nicole Gadda

What does it mean? 

Flagella are small, threadlike structures on microscopic organisms like bacteria that enable movement of a single cell. By using flagella, cells can “swim” to different locations in their environment to access nutrients or escape danger. Similar to a car, flagella are powered by a tiny motor that provides energy for movement, and a stator that controls direction of the cell. Eukaryotic cells like animal, plant, and protozoan cells also can possess flagella, although their structure and mechanics are slightly different from prokaryotic cells like bacteria. 

How do I use it in a sentence?

Similar to a fish using its tail to swim in the ocean, bacterial cells use flagella to swim in their environment.

A bacterial cell with multiple, threadlike flagella is pictured. The bacterium is Helicobacter pylori, a bacteria that causes stomach infections. The cell body is dark gray (purple arrow), and the flagella are long, thin, white structures extending from the cell body (green arrows). Image by Dr. Yutaka Tsutsumi via Wikimedia Commons. Annotations added by the author. 

Etymology: From the Latin word “flagellum,” or “to whip.” 

History of usage: Usage began in 1837.

Related terms: 

Cilia
Fimbriae
Pili
Taxis

Misconceptions: The word “flagella” is plural. “Flagellum” is used to describe a single structure. 

Fields of study in which this word is commonly used:

Microbiology
Cell biology
Genetics