on cell surface, There are often found cilia and flagella, which are a bulk with hair-like structure functioning as movement apparatus. In the structure, there is microtubulen called axoneme.
Cilia has 0.2 um in diameter, 8 um of length, and is mostly found in unicellular organism. In higher level animal, the cilia can be found in membrane tissues of respiratory tract.Thera are hundreds of cilia in one cell. Cilia ( singular: cilium) move or beat in a single direction.
Flagella is longer than cilia, every cell normaly has 1-2 flagella. The buck of cell can move to many direction. It can be found in Protozoa (Flagellata), Porifera (sponges), and Coelenterata (coral animals).