ETC Flashcards
What are the two major roles of the electron transport chain/oxidative phosphorylation?
re-oxidize cofactors from TCA cycle, produce ATP
Through the electron transport chain, ________ from NADH and FADH2 are eventually transferred to ________, forming water.
electrons and O2
Where is the electron transport chain located in the mitochondria?
inner membrane
What makes up the electron transport chain?
series of electron-transfer carriers bound to proteins embedded in inner mitochondrial membrane
The principle of the electron transport chain is movement from most negative to most positive _______ potentials.
redox
How many complexes are there is the electron transport chain?
4
At what complex of the electron transport chain do NADH/H+ molecules begin?
Complex I
At what complex of the electron transport chain do FADH2 molecules being?
Complex II
Complex I of the electron transport chain is known by which two enzyme names?
NADH dehydrogenase (NADH oxidized), NADH-CoQ reductase (NADH oxidized, CoQ reduced)
Complex II of the electron transport chain is known by which two enzyme names?
succinate dehydrogenase (succinate oxidized), succinate-CoQ reductase (succinate oxidized, CoQ reduced)
Co-enzyme Q of the electron transport chain is known by which two names?
CoQ, ubiquinone
What is the role of Cytochrome C in the electron transport chain?
shuttle between Complex III and Complex IV
Complex IV of the electron transport chain is known by which three names?
cytochrome oxidase (cytochrome oxidized), cytochrome a-a3, cytochrome c oxidase
Cytochromes only contain ______-iron complexes.
heme
What is responsible for the modification of the Fe2+/Fe3+ redox potential?
different environment
What is the only electron transport chain carrier that is not a protein-bound co-factor?
coenzyme Q
Is Coenzyme Q lipophillic? Why or why not?
yes, because it has a long isoprene side chain
Heme-iron complexes have what shape?
octahedral
What is the only complex of the electron transport chain that has both heme-iron and iron-sulfur complexes?
Complex III
Which complex of the electron transport chain contains the binding site for oxygen?
complex IV
What is the only complex of the electron transport chain that has copper complexes?
complex IV
Oxidation of reduced cytochrome c by cytochrome c oxidase (complex IV) is coupled to __________.
proton transport
In the proton transport needed for the oxidation of reduced cytochrome c by cytochrome c oxidase (complex IV), are protons being pumped in or out of the liposome, and how many are being pumped?
2 protons pumped out (pH in liposome increases, pH outside decreases)
Besides protons being pumped out of the cytochrome c oxidase liposome (in oxidizing cytochrome c), what else contributes to decreased proton concentration inside the liposome?
formation of water
The reduction of oxygen to water in cytochrome c oxidase (complex IV) is a result of the interaction between what two kinds of complexes?
Fe, Cu
In complex I and III, how many protons does 1 NADH cause to be transported out (into intermembrane space of mitochondria)?
4
In complex IV, how many protons does 1 NADH cause to be transported out (into intermembrane space of mitochondria)?
2
If something is said to have a higher redox potential, is its numerical value more positive or more negative?
more negative
In oxidative phosphorylation, the reduction of oxygen to water and the oxidation of the cofactors is coupled to what?
phosphorylation of ADP to ATP
The energy for ATP synthesis arises from a proton gradient across the _______ mitochondrial membrane.
inner
Is the matrix side of the mitochondria positive or negative relative to the intermembrane side?
negative (helps drive proton gradient)
Which F subunit of ATP synthase is responsible for making ATP?
F1
What are the two F subunits of ATP synthase?
F0, F1
Of the subunits of the F1 subunit of ATP synthase, which is responsible for making ATP?
beta subunit
Which subunit of the F1 subunit of ATP synthase rotates to change the shape of the beta subunits?
gamma subunit
What are the three different conformations F1 beta sites undergo in ATP synthesis?
O (open), T (tight), L (loose)
What is going on in the F1 beta site when it’s in the open (O) conformation?
ATP leaves, ADP + phosphate come in
What is going on in the F1 beta site when it’s in the loose (L) conformation?
ADP + phosphate bind