Flagella are the locomotor organ found in the algae. Two main types of flagella are recognized; Tinsel or pantonematic and whiplash or acronematic. Pantonematic are hairy flagella which undergoes a pulling motion, whereas Acronematic are smooth flagella which undergo the whiplash movement. The type of flagella, kind of flagella, number and insertion are the main characteristics for the classification of algae. Motile cells of algae are biflagellate; if it is of equal length then it is known as isokont. If the two flagella are of dissimilar type and unequal length; then it is known as heterokont. The flagellum consists of two central microtubules and a layer of nine doublet peripheral microtubules which is surrounded by a membrane. So this arrangement is referred as 9+2 pattern which is the important feature of eukaryotic flagella. Flagella is absent in the members of Red algae and Blue green algae.
