How do Giardia produce ATP when they lack mitochondria?

Giardia, a protozoan parasite, produces ATP through anaerobic metabolic pathways, primarily by employing a process called substrate-level phosphorylation. Instead of mitochondria, Giardia utilizes enzymes in the cytoplasm and organelles like hydrogenosomes, which facilitate energy production by converting pyruvate into ATP while generating hydrogen gas. This adaptation allows Giardia to thrive in low-oxygen environments, such as the intestines of its hosts.