- 12.1: The Electron Transport Chain
- At the end of the Krebs Cycle, energy from the chemical bonds of glucose is stored in diverse energy carrier molecules: four ATPs, but also two FADH 2 and ten NADH molecules. The primary task of the last stage of cellular respiration, the electron transport chain, is to transfer energy from the electron carriers to even more ATP molecules, the "batteries" which power work within the cell.
- 12.2: ATP and Oxidative Phosphorylation
- Biological oxidation reactions serve two functions: Oxidation of organic molecules can produce new molecules with different properties (e.g., an increase in solubility is observed on hydroxylation of aromatic substrates by cytochrome P450) and Likewise, amino acids can be oxidized to produce neurotransmitters. Most biological oxidation reactions occur, however, to produce energy to drive thermodynamically unfavored biological processes such as protein and nucleic acid synthesis, or motility.
Thumbnail: The electron transport chain in the cell is the site of oxidative phosphorylation in prokaryotes. The NADH and succinate generated in the citric acid cycle are oxidized, releasing energy to power the ATP synthase. Image used with permission (Public Domain; Fvasconcellos).