Practice question

Diplomonads represent anaerobic excavate flagellates within supergroup Excavata characterized by doubled cellular organization: two equal haploid nuclei arranged mirror-symmetrically, originally formed through incomplete cytokinesis, eight flagella arranged in distinct sets, and ventral feeding groove. Functional mitochondria absent due to anaerobic adaptation, replaced by highly reduced organelles termed mitosomes lacking genome, electron transport, and ATP synthesis, retaining only iron-sulfur cluster assembly machinery essential for cytosolic metabolism. Cytoskeletal ventral disc facilitates attachment. Typical example Giardia lamblia causes intestinal giardiasis reflecting parasitic anaerobic lifestyle.