Oxidative phosphorylation

rirarode's version from 2016-12-11 17:35


Question Answer
___ protons transferred for each NADH reoxidized10
___ protons transferred for each FADH2 reoxidized6
overall ATP yield30-32


Question Answer
Complex I nameNADH Q oxidoreductase
Complex I electron flowNADH -> FMN -> Fe-S centers -> ubiquinone (coenzyme Q)
Complex I functiontransfer e-s from hydrophilic electron carrier (NADH) to lipophilic one (ubiquinone), maximize # protons transferred across membrane
Number of protons transferred at Complex I4
Complex II namesuccinate dehydrogenase
Parts of Complex II4 subunits (A-D), 5 prosthetic groups (2 phosphatidylethanolamine, Heme b, ubiquinone, FAD), 3 Fe-S centers
Number of protons transferred at Complex IInone (not enough energy from FADH2 reoxidation)
Energy flow at Complex IIFADH2 --> Fe-S clusters --> Ubiquinone (QH2)


Question Answer
Complex III namecytochrome bc1 complex
Functions of complex IIItransfer electrons from two electron carrier (QH2) to a one electron carrier (cyt c), maximize proton transfer
"Q cycle" at complex III1 oxidation of first QH2 (1 e- to cyt c, one to Q to form Q.-); 2 oxidation of second QH2 (1 e- to cyt c, one to Q.- to regen QH2)
For every two electrons transferred to cyt c1, ___ H+s transferred from matrix --> intermembrane space4
Complex IV namecytochrome oxidase
Complex IV critical functionspump 4 H+s across membrane for every 4 e-s transferred from C2 --> O2; store e-s accepted from cyt c; transfer 4e- to O2
why is it important to transfer electrons to O2 as quickly as possibleavoid formation of reactive oxygen species


Question Answer
where does E to synthesize ATP come from?electrical potential + chemical potential = proton motive force
function of F1 complexbind ADP/ATP, synthase/ATPase function
function of Fo complexprovide energy for ATP synthesis via proton gradient
major energy cost of ATP synthesisreleasing F1-bound ATP (many bonds, very stable)
three states of F1 beta subunitsempty, can bind ADP, can bind ATP
amt of H+ required for 120 degree rotation of gamma stalk4 protons
why can ATP synthase rotate wellhydrophobic interactions in Fo subunit = "lube"
F1 function in isolationATPase (also due to gamma stalk rotation)
thermogenin"uncoupling" protein - H+ movement through generates heat
thermogenin found inBAT, brown adipose tissue
adenine nucleotide translocase is (passive/active), (symport/antiport), and (electroneutral/electrogenic)passive, antiport (w/ ADP), electrogenic
phosphate translocase is (passive/active), (symport/antiport), and (electroneutral/electrogenic)passive, symport (w/ H+), electroneutral