They receive electrons after glycolysis when molecular oxygen is unavailable as the terminal acceptor. Nitrate, sulfate, and carbon dioxide can serve this role, linking electron transfer to different environmental transformations. The available acceptor therefore connects cellular energy production with changes in nitrogen, sulfur, and carbon cycling.
After glycolysis, electron transfer through an electron transport chain creates a proton gradient across a membrane. ATP synthase uses that gradient to drive ATP formation. This mechanism allows anaerobic respiration to remain coupled to membrane-based energy conservation even when oxygen cannot serve as the terminal electron acceptor.
The proton gradient stores energy generated during electron transport in an electrochemical form. ATP synthase then converts that stored energy into ATP, the usable cellular energy currency. Its formation explains how cells can obtain energy from anaerobic electron-transfer pathways rather than relying only on the reactions of glycolysis.
The process begins with glycolysis, followed by electron transfer through an electron transport chain. Electrons then reach an alternative terminal acceptor, such as nitrate, sulfate, or carbon dioxide. Electron transport establishes a proton gradient, and ATP synthase uses it to produce ATP, linking each stage into one energy-conserving sequence.
Anaerobic respiration supports bacteria and archaea in environments where oxygen is limited, including sediments, wetlands, soils, and animal-associated habitats. These settings provide ecological niches in which alternative electron acceptors can support energy production. Studying them helps explain microbial activity in oxygen-depleted parts of natural and host-associated systems.
The process is relevant to wastewater treatment and microbial ecology because it connects microbial energy production with transformations of carbon, nitrogen, and sulfur. It also supports research on life in extreme or oxygen-depleted environments. These applications use anaerobic metabolism to interpret environmental change and the activity of microorganisms in specialized habitats.