Electron Transport Chain &OxidativePhosphorylation
Oxidative PhosphorylationOxidative phosphorylation is the process in which ATP is syntheses as electrons are transferred from NADH + H+ and FADH2to molecular oxygen via the Electron Transport Chain.Oxidative phosphorylation is so called because the NADH + H+ and FADH2 are oxidized to NAD+ and FAD+ respective, as the ADP is phosphorylated to ATP.
Functions of Oxidative Phosphorylation1.Produce ATP2.Regenerate NAD+ and FAD+
Oxidative PhosphorylationAll oxidative steps in the degradation of carbohydrates, fats, and amino acids converge in the final stage of cellular respiration.The Electron Transport Chain is located on the inner mitochondria membrane. The IMM contains: Respiratory electron carriers (complexes I-IV), ADP-ATP translocases, ATP synthase and other membrane transportersThe IMM is impermeable to most small molecules and ions, including H+.
The Electron Transport ChainThe electron transport chain is composed of four multi-enzyme complexes through which electron are transported until the electrons are eventually transferred to molecular oxygen.The electron donor to the electron transport chain protein are NADH + H+and FADH2.
The Electron Transport ChainThe Electron Transport Chain complexed are of progressively low energy level (increasing electron affinity).When NADH and FADH deliver electrons, the electron are split into protons and electrons. The protons are passed into the intermembrane space, while the electrons are transferred along the chain of carriers complexes
The Electron Transport Chain
Complex I: NADH Dehydrogenase ComplexTransfers electrons from NADH to ubiquinoneThe reduced NADH of the chain is oxidized by a metalloflavoprotein enzyme NADH dehydrogenaseThe NADH dehydrogenase molecule includes an FMN-containing flavoprotein and at least 6 iron-sulfur clusters
Complex I: NADH Dehydrogenase ComplexNADH transfers its two high-potential electrons to the flavin mononucleotide (FMN) prosthetic group to give the reduced form, FMNH2.NADH + H++ FMN → FMNH2 + NAD+Electrons are then transferred from FMNH2through a series of iron-sulfur clusters to Coenzyme Q (ubiquinone) to form ubiquinol (QH)
Complex I: NADH Dehydrogenase ComplexFlow of electrons from NADH to QH2through