Arrangement of Bacterial Flagella

How Many Flagella Does a Bacterium Have?

How Are They Arranged?

There are basically four different types of flagellar arrangements:
1. A single flagellum can extend from one end of the cell - if so, the bacterium is said to be monotrichous.
2. A single flagellum (or multiple flagella; see below) can extend from both ends of the cell - amphitrichous.
3. Several flagella (tuft) can extend from one end or both ends of the cell - lophotrichous; or,
4. Multiple flagella may be randomly distributed over the entire bacterial cell - peritrichous.

Discrepancies in Definitions

amphi- a prefix meaning both or on both sides, as in amphimorphic.
amphitrichous Microbiology, having a single flagellum at each end of the cell, as do certain bacteria. Also, amphitrichate.
lopho- or loph- a combining form meaning a "ridge" or "tuft," as in lophodont, lophophore.
lophotrichous Cell Biology, describing flagella that are arranged in a tuft at the pole of a cell.

amph(i)- [Gr. Amphi on both sides] a prefix meaning on both sides; around or about; double.
amphitrichous (am-fit¢ re-kus) [amphi- + Gr. thrix hair] having a single flagellum, or a single tuft of flagella, at each end; said of a bacterial cell.
loph(o)- [Gr. lophos ridge, tuft] a combining form denoting a relationship to a ridge or to a tuft.
lophotrichous (lo-fot¢ ri-kus) [lopho- + Gr. thrix hair] having two or more flagella at one or both ends; said of a bacterial cell.