A centriole is an organelle found only in eukaryotes that develop cilia or flagella. They have two functions namely:
Centrioles are composed of two short cylindrical bundles of microtubules. Generally one centriole is at right angles to the other.
Each centriole is a set of nine groups of microtubule pairs arranged in a pinwheel (see below).
Cilia and flagella are fine, hairlike, movable organelles found on the surfaces of some cells. Although these organelles appear to be outside the cell they are both surrounded by the plasma membrane.
Cilia can be used to move a single cell as in the protist paramecium or they can be used to move material past a cell as in the epithelial cells lining the bronchial passages.
Take a quiz on basic cell structure at the Biology 101 site.
Modified July 10, 2005