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electron transport chain by sunil shah (bond king) and groups..

electron transport chain by sunil shah (bond king) and groups..

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    ETCs ETCs Presentation Transcript

    • Group – 3Shah Sunil and Groups
    • Respiration Respiration Involves : Glycolysis, Krebs cycle, Electron transport and Oxidative Phosphorylation
    • INTRODUCTION Glycolysis : Occurs in the cytoplasm. Breaks glucose into two molecules of pyruvate. Krebs cycle : occurs in the mitochondrial matrix. degrades pyruvate to carbon dioxide. Several steps in glycolysis and the Krebs cycle transfer electrons from substrates to NAD+, forming NADH. NADH passes these electrons to the electron transport chain.
    • Mitochondria stage 3rd of respiration Occurs in mitochondria.
    • Mitochondria Outer membrane- permeable to small molecules Inner membrane- electron transport ATP synthase Cristae increase area Integrity required for coupling ETS to ATP synthesis
    • Mitochondria outer membrane relatively permeable inner membrane permeable only to those things with specific transporters ◦ Impermeable to NADH and FADH2 ◦ Permeable to pyruvate Compartmentalization ◦ Krebs and β-oxidation in matrix ◦ Glycolysis in cytosol
    • Electron Transport System Electron Transport Chain – is a collection of molecules embedded in the inner membrane of the mitochondria ◦ Most components are proteins
    • Electron Transport System Mechanism the cell that converts the energy in NADH and FADH2 into ATP. Electrons flow along an energy gradient via carriers in one direction from a higher reducing potential to a lower reducing potential The ultimate acceptor is molecular oxygen. At the end of the chain electrons are passed to oxygen forming water.
    • Electron Transport System An NADH molecule begins the process by “dropping off” its electron at the first electron carrier molecule
    • ETS Remember: each component will be 50 NADH reduced when it accepts 40 I FADH2 FAD Multiprotein FMN complexes Free energy (G) relative to O2 (kcl/mol) the electron and oxidized Fe•S O Fe•S Cyt b II III when it passes the 30 Fe•S Cyt c1 Cyt c IV electron down to the more 20 Cyt a Cyt a3 electronegative carrier molecule in the chain 10 0 2 H ++ 12 O2 H2 O
    • Finally the electron is passed tooxygen, which is very electronegative. NADH 50 FADH2 I Multiprotein 40 FAD Free energy (G) relative to O2 (kcl/mol) FMN complexes Fe•S II The oxygen also picks Fe•S O Cyt b III Fe•S up 2 H+ ions from the 30 Cyt c1 Cyt c IV Cyt a aqueous solution and 20 Cyt a3 forms water 10 0 2 H ++ 12 O2 H2 O
    • ETS FADH goes through 50 NADH mostly the same FADH2 Multiprotein Free energy (G) relative to O2 (kcl/mol) 40 I FAD processes, except it FMN complexes Fe•S Fe•S II O III Cyt b drops off its electron 30 Fe•S Cyt c1 Cyt c IV at a lower point on Cyt a Cyt a3 20 the ETC 10 0 2 H ++ 12 O2 H2O
    • The ETC makes no ATP directly!The ETC releases energy in a step-wise series of reactionsIt powers ATP synthesis via oxidativephosphorylation.But it needs to be coupled withchemiosmosis to actually make ATP.
    • Oxidative PhosphorylationProduction of ATP usingtransfer of electrons for energy Some ATP is produced by substrate-level phosphorylation during glycolysis and the Krebs cycle, but most comes from oxidative phosphorylation
    • Oxidative phosphorylation CONCEPT : During oxidative phosphorylation, chemiosmosis couples electron transport to ATP synthesis
    • Chemiosmosis The Energy-Coupling Mechanism Inner membrane of mitochondria has many protein complexes called ATP synthase ◦ ATP synthase – enzyme that makes ATP from ADP and inorganic phosphate It uses the energy of an existing gradient to do this.
    • The existing gradient is the difference in H+ ion concentration on opposite sides of the inner membrane of the mitochondria Inner Mitochondrial Oxidative Glycolysis phosphorylation. membrane electron transport and chemiosmosis ATP ATP ATP H+ H+ H+ H+ Protein complex Cyt cIntermembrane of electronspace carners Q IV I III ATPInner II synthasemitochondrial FADH2 FAD+ 2 H+ + 1/2 O2 H2Omembrane NADH+ NAD+ ADP + Pi ATP (Carrying electrons from, food) H+Mitochondrial Electron transport chain Chemiosmosismatrix Electron transport and pumping of protons (H +), ATP synthesis powered by the flow which create an H+ gradient across the membrane Of H+ back across the membrane Oxidative phosphorylation
    • Chemiosmosis Chemiosmosis – the process in which energy stored in the form of a hydrogen ion gradient across a membrane is used to drive cellular work (like the synthesis of ATP)
    •  It is the job of the ETC to create this H+ ion gradient Inner Mitochondrial Oxidative Glycolysis phosphorylation. membrane electron transport and chemiosmosis ATP ATP ATP H+ H+ H+ H+ Protein complex Cyt cIntermembrane of electronspace carners Q IV I III ATPInner II synthasemitochondrial FADH2 FAD+ 2 H+ + 1/2 O2 H2Omembrane NADH+ NAD+ ADP + Pi ATP (Carrying electrons from, food) H+Mitochondrial Electron transport chain Chemiosmosismatrix Electron transport and pumping of protons (H+), ATP synthesis powered by the flow which create an H+ gradient across the membraneOf H+ back across the membrane Oxidative phosphorylation
    • H+ ions are pumped into theintermembrane space by the ETCThe H+ ions want to drift back into thematrix.But they can only come into the matrixeasily through ATP synthase channels
    • A protein complex, ATPsynthase, in the cristaeactually makes ATP fromADP and Pi.ATP used the energy ofan existing proton gradientto power ATP synthesis. proton gradientdevelops between theintermembrane spaceand the matrix.
    • Mitochondrial redox carrierNADH Complex I Q Complex III Complex IIComplex IV FADHO2
    • 4 Complexes proteins in specific order Transfers 2 electrons in specific order ◦ Proteins localized in complexes  Embedded in membrane  Ease of electron transfer ◦ Electrons ultimately reduce oxygen to water  2 H+ + 2 e- + ½ O2 -- H2O
    • Complex I Has NADH binding site ◦ NADH reductase activity  NADH - NAD+ ◦ transfers to electron carriers ◦ NADH (nicotinamide adenine dinucleotide )
    • Passes them to coenzyme Q ( Ubiquinone )Also receive electron from complex II
    • Complex II succinate ---FAD—ubiquinone ◦ Contains coenzyme Q ◦ FADH2 binding site  FAD reductase activity  FADH2 -- FAD  conversion of succinate to fumerate
    • Mitochondrial redoxcarriers
    • Complex III ubiquinone - ubiquinone while cytochrome C gets reduced Also contains cytochromes b NADH generates more energy than FADH2
    • Complex IV reduction of oxygen cytochrome oxidase oxygen ---> water ◦ 2 H+ + 2 e- + ½ O2 -- 2 H2O ◦ transfers e- one at a time to oxygen
    • ATP Produced◦ The NADH from glycolysis may also yield 3ATP. Krebs cycle can be used to generate about 2ATP. Electron transport chain yield 32 ATP.
    • ATP Produced About 40% of energy glucose moleculetransferred to ATP during cellular respiration Makes approximately 38 ATP.
    • Conclusion /ResultOVERALL yield fromglucose 36-38 ATPs
    • THANK YOUGROUP -3SHAH SUNIL KUMARGIRI JEMYTIMILSINA BINODMAJHI INDRAABDHIKINIWARSAMEMOHAMMAD ABDIKALI