electron-transport chain (respiratory chain) A system of electron carriers, present in mitochondria and the cell membranes of prokaryotes, which sequentially transport electrons and/or protons previously removed from metabolites in glycolysis, the citric-acid cycle, and other metabolic reactions.

electron-transport chain
1. Respiratory chain. A system of redox compounds called electron carriers, present in mitochondria, which sequentially transport electrons and/or protons previously removed from metabolites in glycolysis, the citric-acid cycle, and other metabolic reactions.

2. A system of redox compounds involved in electron transport in metabolic pathways such as photosynthesis.