Q2W6-Oxidative Phosphorylation PDF

NOW SHOWING OXIDATIVE PHOSPHORYLATION EULA FAITH MIRACLE V. ANDAM Teacher III Objectives: Describe the movement of electrons through the electron transport chain State the products of oxidative phosphorylation Outline the role of NADH and FADH2 and electron carriers in the el...

NOW SHOWING OXIDATIVE PHOSPHORYLATION EULA FAITH MIRACLE V. ANDAM Teacher III Objectives: Describe the movement of electrons through the electron transport chain State the products of oxidative phosphorylation Outline the role of NADH and FADH2 and electron carriers in the electron transport chain Describe the chemiosmotic theory of ATP production ⦿ Oxidative phosphorylation also known as the electron transport chain is a series of a series of proteins and organic molecules found in the inner membrane of the mitochondria. Electrons are passed from one member of the transport chain to another in a series of redox reactions. ⦿ Chemiosmosis is when H++ ions passively move “downstream” across a semipermeable membrane (from a higher to a lower ion concentration). The proton flow across the mitochondrion inner membrane, down the H++ gradient built up by the ETC.  NADH-coenzyme Q oxidoreductase (complex I) ⦿ also known as NADH dehydrogenase ⦿ Start binding of a NADH molecule to complex I and the donation of two electrons. The electrons enter complex I via a prosthetic group attached to the complex, flavin mononucleotide (FMN). The addition of electrons to FMN converts it to its reduced form, FMNH2. The electrons are then transferred through a series of iron–sulfur clusters. ⦿ As the electrons pass through this complex, four protons are pumped from the matrix into the intermembrane space. Finally, the electrons are transferred from the chain of iron–sulfur clusters to a ubiquinone molecule in the membrane. Reduction of ubiquinone also contributes to the generation of a proton gradient, as two protons are taken up from the matrix as it is reduced to ubiquinol (QH2).  Succinate-Q oxidoreductase (complex II) ⦿ also known as succinate dehydrogenase, ⦿ it is the only enzyme that is part of both the citric acid cycle and the electron transport chain. ⦿ It oxidizes succinate to fumarate and reduces ubiquinone. As this reaction releases less energy than the oxidation of NADH, complex II does not transport protons across the membrane and does not contribute to the proton gradient.  Q-cytochrome c oxidoreductase (complex III) ⦿ also known as cytochrome c reductase, cytochrome bc1 complex ⦿ oxidation of one molecule of ubiquinol (Q) and the reduction of two molecules of cytochrome c ⦿ only one proton transferred per cytochrome c reduced  Cytochrome c oxidase (complex IV) ⦿ final protein complex in the electron transport chain ⦿ This enzyme mediates the final reaction in the electron transport chain and transfers electrons to oxygen, while pumping protons across the membrane. ⦿ Oxygen reduced to water  ATP synthase (complex V) ⦿ enzyme is found in all forms of life and functions in the same way in both prokaryotes and eukaryotes ⦿ uses the energy stored in a proton gradient across a membrane to drive the synthesis of ATP from ADP and phosphate (Pi) Overall, what does the electron transport chain do for the cell? (It has two important functions) Regenerates electron carriers.  Makes a proton gradient.  Note: ATP synthesis 1 NADH= 3 ATP 1 FADH2= 2 ATP ⦿ Glycolysis › 2 ATP › 2 NADH ⦿ Pyruvate Oxidation/ Link Reaction › 0 ATP › 2 NADH ⦿ Krebs cycle › 2 ATP › 6 NADH › 2 FADH2 TOTAL: 36-38 ATP (Aerobic Respiration)  ATP Synthesis ⦿ Source: http://www.bioinfo.org.cn/book/biochemistry/chapt18/sim5.htm