Oxidative Phosphorylation/Electron Transport Chain Flashcards
oxidation phosphorylation is the
oxidation of high-energy electron carriers, which are coupled to the phosphorylation of ADP to produce ATP
electron carriers include NADH, FADH2
oxidation phosphorylation creates a proton gradient by
oxidizing high-energy electron carriers which release energy which is used to pump hydrogen protons
oxidation phosphorylation takes place in
the mitochondria via the matrix and inter-membrane space
*protons are release into inter-membrane space while oxidation/reduction/krebs cycle is in the matrix
electron transport chain is composed of how many complexes?
5 total (including ATP synthase)
the overall redox reaction is
2H+ + 2e- + 1/2O2 = H2O + energy
complex I: NADH-coenzyme Q reductase
it is organized so that complex I receives two electrons from NADH, which is oxidized into NAD+ from the NADH dehydrogenase (aka coenzyme Q reductase) enzyme present in complex I
the NADH hydrogenase pumps 4 H+ into intermembrane
the electrons are passes onto mobile molecule, ubiquinone (Q) to be taken to complex III
FMN and Fe-S are present
complex II: succinate-coenzyme C reductase
succinate is oxidized into fumarate by succinate dehydrogenase enzyme (aka coenzyme C reducatase), causing FAD to be reduced to FADH2
FADH2 is then reoxidized to donate electrons to ubiquinone (Q), becoming QH2 to be taken to complex III
*complex II does not pump protons into intermembrane space
*ubiquinone (Q) connect complex I and II to complex III
complex III: coenzyme Q-cytochrome C reductase
QH2 is oxidized and its electrons are passed onto another electron carrier protein called cytochrome C (reduced)
the passage of electrons into complex III drives the transport of four more H+ ions into intermembrane
complex IV: cytochrome C oxidase
the electrons from cytochrome C are oxidized and use by oxygen to yield water
during this reaction more protons are released
complexes I, III, and IV are cyctochromes because
they contain heme groups and porphyrin ring containing a tightly bound iron atom
chemiosmotic coupling is
the drive of active transport of protons from the intermembrane space to the matrix (through ATP synthase complex)
complex V: ATP synthase
from a high concentration gradient it allows for ATP generation opportunity
the ATP synthase has three binding sites on the matrix side for ADP and Pi, once bonded there is confirmation change and complex rotates so that ADP can bind a free Pi to make ATP
total production of oxidative phosphorylation is
32 ATP generated in the electron transport chain
