1. Electron Transport Chain

2. Review Glycolysis & the Krebs Cycle only produce 4 ATP/glucose Most of the energy from glucose is stored in NADH or FADH 2

3. Location The Electron Transport Chain (ETC) takes place along the Inner Mitochondrial Membrane

4. Components Most components of the Electron Transport Chain are protein complexes These complexes have Prosthetic Groups ◦ Essential non-protein components

5. The entire Electron Transport Chain consists of 4 transmembrane structures as well as a pair of electron carriers Most structures are made up of more than one protein

7. NADH Dehydrogenase (Complex I) NADH is oxidized and in turn reduces flavin mononucleotide (FMN) FMN participates in another redox reaction with an Iron-Sulfur protein ◦ FMN is oxidized, FeS is reduced

8. First Electron Carrier FeS part of NADH Dehydrogenase pass the electrons to Ubiquinone (Q) ◦ Lipid electron carrier ◦ Transports the electrons to Cytochrome b-c 1 complex

9. Cytochrome b-c 1 Complex (Complex III) Cytochrome b (Cyt b) accepts the electrons from Q Electrons are passes from Cyt b to another iron-sulfur protien before being passed to Cytochrome c 1

10. Second Electron Carrier Cytochrome c 1 passes the electrons to the second electron carrier, Cytochrome c Cytochrome c operates on the outside of the inner mitochondrial membrane (in the intermebrane space)

11. Cytochrome Oxidase Complex (Complex IV) Consists of two protein complexes: Cytochrome a and Cytochrome a 3 Cytochrome a receives the electrons from Cytochrome c and then transfers electrons to Cytochrome a 3 Cytochrome a 3 passes the electrons onto Oxygen ◦ Combines with hydrogen atoms in the Matrix to form water

13. Each transfer of electrons is an exothermic redox reaction ◦ The energy is used to transfer a single H + ion into the Intermembrane Space Oxygen (due to its high electronegativity) is the only element available to accept electrons at the end

14. FADH 2 transfers its electrons to a lower energy level than NADH Electrons join up with Ubiquinone (Q) hence NADH  3 H + moved FADH 2  2 H + moved FADH 2 FAD

15. Chemiosmosis The final stage of Oxidative Phosphorylation The complexes of the ETC create a electrochemical gradient of H + across the inner membrane ◦ H + want to return to equilibrium

16. ATP Synthase Protein imbedded in the inner mitochrondia membrane Allows H + ions back through into the matrix Uses this Proton- Motive Force to convert ADP and ATP ◦ Each H + ion let back into the matrix creates 1 ATP

17. Energy Tally/Glucose Molecule Glycolysis2 ATP Krebs Cycle2 ATP ETC NADH (Glycolysis)4-6 ATP NADH (Prep Step)6 ATP NADH (Krebs)18 ATP FADH 2 4 ATP 36-38 ATP