RT Book, Section A1 Ryan, Kenneth J. SR Print(0) ID 1185635802 T1 Sarcomastigophora—The Flagellates T2 Sherris & Ryan's Medical Microbiology, 8th Edition YR 2022 FD 2022 PB McGraw-Hill Education PP New York, NY SN 9781260464283 LK accessmedicine.mhmedical.com/content.aspx?aid=1185635802 RD 2024/04/25 AB The flagellated protozoa are widespread in nature, multiply by binary fission, and move about by means of a primary organelle of locomotion, the flagellum. This organelle arises from an intracellular focus known as a kinetosome (basal body), extends to the cell wall as a filamentous axoneme composed of microtubules arranged in the typical 9 pairs + 2 central microtubular pattern, and continues extracellularly as the free flagellum. A pair of dynein arms extends from each outer microtubule of a pair to an adjacent microtubular pair and is responsible for flagellar beating through ATP hydrolysis. The long, whip-like free flagella may be single or multiple. The number is distinctive for individual species. When more than one flagellum is present, each has its own associated basal body and axoneme. The entire flagellar unit and any associated organelles are referred to as a mastigont system.