What are cilia and flagella?

Cilia and flagella are structures found in prokaryotes as well in eukaryotic cells. They play defense, nutrition and movement roles for the cell. In eukaryotic cells of protists and animals they create from centrioles that migrate towards the plasma membrane and distinguish into structures projected outside the cell. Every cilium or flagellum is made of nine peripheral pairs of microtubules and single central pair all covered by membrane. (In bacteria, flagella are made of a protein named flagellin and there can too be fimbria made of pilin.)