Transmission electron micrographs of T. gondii tachyzoites in cell culture (A) Tachyzoite in a parasitophorous vacuole (pv) in the cytoplasm of a host cell. Note conoid (c), rhoptries (r), micronemes (mi), nucleus (n), and dense granules (d). The host cell mitochondria (mt) are closely associated with the pv (Bar = 0.5 μm). (B) Several tachyzoites in pv (Bar = 1.8 μm).