electron transport chain. review glycolysis & the krebs cycle only produce 4 atp/glucose most of...
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Electron Transport ChainElectron Transport Chain
ReviewReviewGlycolysis & the Krebs Cycle only
produce 4 ATP/glucoseMost of the energy from glucose
is stored in NADH or FADH2
LocationLocationThe Electron
Transport Chain (ETC) takes place along the Inner Mitochondrial Membrane
ComponentsComponentsMost components
of the Electron Transport Chain are protein complexes
These complexes have Prosthetic Groups◦ Essential non-
protein components
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
NADH Dehydrogenase NADH Dehydrogenase (Complex I)(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, Fe•S is reduced
First Electron CarrierFirst Electron CarrierFe•S part of NADH
Dehydrogenase pass the electrons to Ubiquinone (Q)◦Lipid electron carrier◦Transports the electrons to
Cytochrome b-c1 complex
Cytochrome Cytochrome bb--cc11 Complex Complex (Complex III)(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 c1
Second Electron CarrierSecond Electron CarrierCytochrome c1 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)
Cytochrome Oxidase Cytochrome Oxidase Complex (Complex IV)Complex (Complex IV)Consists of two protein complexes:
Cytochrome a and Cytochrome a3
Cytochrome a receives the electrons from Cytochrome c and then transfers electrons to Cytochrome a3
Cytochrome a3 passes the electrons onto Oxygen◦Combines with hydrogen atoms in the
Matrix to form water
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
FADH2 transfers its electrons to a lower energy level than NADH Electrons join up with
Ubiquinone (Q) hence
NADH 3 H+ moved
FADH2 2 H+ moved
FADH2
FAD
ChemiosmosisChemiosmosisThe final stage of Oxidative
PhosphorylationThe complexes of the ETC create
a electrochemical gradient of H+ across the inner membrane◦H+ want to return to equilibrium
ATP SynthaseATP SynthaseProtein 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
Energy Tally/Glucose Energy Tally/Glucose MoleculeMoleculeGlycolysis 2 ATPKrebs Cycle 2 ATPETC
NADH (Glycolysis) 4-6 ATPNADH (Prep Step) 6 ATPNADH (Krebs) 18 ATPFADH2 4 ATP
36-38 ATP