Final answer:
Anaerobic respiration functions without oxygen by using other inorganic molecules like nitrate, sulfate, and carbon dioxide as final electron acceptors in the ETC to produce ATP.
Step-by-step explanation:
Anaerobic respiration utilizes inorganic electron acceptors other than O₂, such as NO₃(-) (nitrate), SO₄(2-) (sulfate), Fe(3+) (ferric ion), CO₂. These inorganic molecules are used by various microorganisms when oxygen is not available to accept the electrons at the end of the electron transport chain (ETC). In this process, different microbes utilize various inorganic molecules, such as nitrate in the case of denitrifying bacteria or sulfate in the case of sulfur bacteria, both leading to the production of ATP in the absence of oxygen. Moreover, microbes utilizing anaerobic respiration typically maintain an intact Krebs cycle and may have specialized electron transport systems to facilitate this process.