The key metabolic pathway of cellular respiration.
Good animation explaining it: Video "Electron transport chain by HarvardX (2017)".
Articles by others on the same topic
The citric acid cycle is a metabolic pathway that accepts a two-carbon acetyl group from acetyl-CoA, releases two carbon dioxide molecules per turn, and regenerates its four-carbon acceptor, oxaloacetate. Its oxidation steps load electron carriers; oxidative phosphorylation subsequently uses their electrons to support ATP production. In mitochondria, most steps occur in the mitochondrial matrix, while succinate dehydrogenase lies in the inner mitochondrial membrane.[ref]
How Cells Obtain Energy from Food. Molecular Biology of the Cell, 4th edition by Bruce Alberts and others; Chapter 2, How Cells Obtain Energy from Food, The Citric Acid Cycle Generates NADH by Oxidizing Acetyl Groups to CO2; Figure 2-79 and Panel 2-9
The economy is striking: the acceptor is rebuilt rather than supplied anew for every incoming acetyl group. Regeneration does not create extra oxaloacetate. Withdrawal of intermediates for amino acid synthesis must be balanced by replenishment if the available pool is to remain steady. Thus the citric acid cycle connects energy metabolism to synthesis as well as to breakdown.[ref]
How Cells Obtain Energy from Food. Molecular Biology of the Cell, 4th edition by Bruce Alberts and others; Chapter 2, How Cells Obtain Energy from Food, final paragraph of The Citric Acid Cycle Generates NADH by Oxidizing Acetyl Groups to CO2: oxaloacetate and alpha-ketoglutarate as biosynthetic precursors