Final answer:
Trichomonas vaginalis utilizes flagella and an undulating membrane for motility, and it is a parabasalid protozoan causing trichomoniasis. With amoeboid and oval forms, it adheres to cells via adhesins and lacks a cyst stage.
Step-by-step explanation:
The structure of motility in Trichomonas vaginalis is largely due to its flagella and undulating membrane, which enable the protozoan to move and adhere to cells in the urogenital system. Trichomonas vaginalis is a parabasalid protozoan, meaning it belongs to the phylum Parabasalia. This organism is responsible for causing trichomoniasis, the most common nonviral sexually transmitted infection (STI) globally. In addition, Trichomonas vaginalis exhibits an amoeboid shape when attached to vaginal cells and is oval-shaped in culture. It adheres to cells using virulence factors such as adhesins and tetraspanins, which are also critical for motility and invasion of host tissues. Unlike other pathogens, it exists only as a trophozoite and does not form cysts.