BICH 411 1st Edition Lecture 8Outline of Previous LectureI. Reaction 3 (TCA cycle)II. Reaction 4III. Reaction 5IV. Reaction 6V. Reaction 7VI. Reaction 8VII. AnaplerosisVIII. GlyoxylateOutline of Current Lecture I. Electron Transport OverviewII. Complex IIII. Complex IIIV. Complex IIIV. Q cycleVI. Complex IVVII. supercomplexesCurrent LectureThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.-FADH2 and NADH carry electrons through protein complexes. Eventually, this will create a protein gradient in the mitochondria. -There are 4 protein complexes in the mitochondria.-Ubiquinone (UQ) is hydrophobic, so it stays in the core of the membrane bilayer-Cytochrome C and UQ help carry electrons-electrons always go toward more positive reduction potentials! This is much more energeticallyfavorable **review figure 20.2**it’s important to note that complexes I and II have lots of Fe/S centers!!**For table 20.1, know which prosthetic groups (coenzymes) go in which complex and how theywork***Figure 20.3 is important to know for the exam. The electrons in complexes I and II are collected through catabolism. Complex IV doesn’t have any Fe/S centers!! (good test question) Protons ultimately moved to O2 to form H2O. (2 H2O for every 1 O2).-UQ has a long, very hydrophobic tail, which helps it stay in the membrane. (UQH2 is ubiquinol, the alcohol form of ubiquinone).Complex I-oxidizes NADH back to NAD+; this is a very big complex!!!-the electrons are transferred to UQ-**electron path: NADHFMNFe-SUQFe-SUQ-the energy of this reaction is enough to pump 4 hydrogens from the matrix for ever 2 electrons.Eventually when there are only few protons in the matrix, the proton gradient will form.-paralysis among heroin addicts due to bad heroin with MPTP. It can deteriorate parts of the brain. Treated with L-Dopa and fetal brain tissue implantation. MPP+ poisons complex 1*** (good exam question).Complex II-very rich in Fe-S centers!-this complex interacts with the succinatefumarate step in the TCA cycle-net reaction: succinate + UQ  fumarate + UQH2***no protons are transported in complex II – there isn’t enough energy!Complex III-gets electrons from UQ pool, passes them to cytochrome c-pumps protons with Q cycle- b cytochrome  hemes bL (low reduction potential) and bH (high reduction potential)-cytochrome C is the electron acceptor at the end of complex III***it’s important to note that UQH can carry 2 electrons, but cytochrome C can only carry one electronQ-cycle – part of complex III1st half of Q cycle: takes molecules from UQ pool to Qp site. 2 hydrogens are pumped out. An electron from UQH2 goes to an Fe-S center and then to cytochrome C. UQ also goes to QP site and that electron goes to cytochrome bL. It then passes to cytochrome bH to bind with UQ and form UQ- (semiquinone) in the Qn site. UQ- binds very tightly to it’s electron. 2nd half of Q cycle: QP site is the exact same. 2 more protons are pumped out. UQ- at the Qn site gains another electron from cytochrome bH and is then protonated to form UQH2.Complex IV-electrons are moved from cytochrome c (one electron at a time)**no iron-sulfur centers!!-has 2 copper sites-2 hydrogens are pumped out-figure 20.17 – it’s important to note that the proton that enters is NOT the same on that leaves!They travel from water molecule to water molecule.Supercomplexes-aka respirasomes -occasionally the complexes are combined, coupling the transport reactions**memorize figure