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Download Chapter 18 Electron Transport and Oxidative Phosphorylation
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Chapter 18 Electron Transport and Oxidative Phosphorylation Overview of electron transport IIntermembrane t b space Inner Outermembrane Redox Potentials The bigger the number The greater the electron affinity The electron transport Chain is UNI-directional System based upon INCREASING REDOX POTENTIALS The Final acceptor is Oxygen! Mobile electron Carriers, carry electrons Between the stationary carriers Electrons Flow!!! http://vcell.ndsu.nodak.edu/animations/etc/movie.htm Cytochrome C is a conserved Molecule Its role It l to t shuttle h ttl electrons l t between b t stationary t ti complexes l Has NOT changed for billions of years!!! Comparing Cytochrome y C Genes to form A phylogenetic Tree The more similar The amino acid Sequence if of cytochrome C, The more closely related the Species are are. The Hazards of the electron transport chain. An oxygen that is not completely Reduced to water will form free radicals. Superoxide Dismutase (SOD) enzyme helps to clear the Free radicals. The generation of a proton gradient – the theory The proton gradient powers ATP production A Test of the theory in An artificial system (mitochondria) ATP Synthase is an elaborate Molecular Energy converter! 11. Converts potential energy of a proton gradient into kinetic energy Of rotation! 2. Rotational kinetic energy it converted into chemical potential energy in an ATP Molecule! The process is called oxidative Phosphorylation! It makes ATP more efficiently than Substrate level phosphorylation! Detecting rotation – Fixed the bottom of ATP synthase On a glass slide, and tethered A fluorescent actin filament H dl on to the Handle h rotating i Gama (g) subunit Added ATP and observed… http://www.res.titech.ac.jp/~seibutu/hisabori/fig2.mov http://vcell.ndsu.nodak.edu/animations/atpgradient/movie.htm Translocase antiporter in the mito innermembrane help Move ATP out and ADP in the matrix ~30 ATPs Per glucose Opening p g the Flood Gates! Releasing g the Stored Energy Randomly! Opening the “Flood Flood Gates”! Gates ! Releasing the Stored Energy Randomly! Skunk cabbage UCP-1 Uncouples the gradient = thermogenesis Hibernation Infant mammals “nonshiver” heat generation Inhibitors of the electron T Transport t chain h i Good or Bad for ATP production? A chemical “uncoupler” of the proton gradient
