Electron Transport: Complex II Flashcards
True or false: The free energy generated by the transfer of electrons from succinate to CoQ is sufficient to drive ATP synthesis.
False
What does Complex II catalyze?
Contains the TCA enzyme succinate dehydrogenase which passes electrons from succinate to CoQ.
Which enzyme in the TCA Cycle catalyzes the formation of FADH2?
Succinate dehydrogenase; it is also part of Complex II in the electron transport chain
What is the structure of Complex II
It is an integral membrane protein of the inner mitochondrial membrane. Succinate dehydrogenase is covalently bonded to it. It’s electron carriers are FAD, iron-sulfur clusters, and CoQ.
Why is Complex II important?
It allows high energy electrons to enter electron transport by by-passing Complex I
What is the term for redox proteins containing heme groups with various side chain substitutions?
Cytochromes
What oxidation states does heme iron alternate between during electron transport?
Fe2+ and Fe3+
How many electrons do NADH and FADH2 each carry?
2 electrons each
Which type of cytrochromes contain protoporphyrin IX (as in Hb and Mb)?
b-type cytochromes
Which type of cytrochromes contain protoporphyrin IX that have added Cys sulfhydryls across vinyl groups that form thioester linkages to protein?
c-type cytochromes
Which type of cytochromes contain heme with long isoprene substituion?
a-type cytochromes
True or false: Complex I and II have different roles and operate in sequence.
False; they each perform the same function, transfer of electrons from NADH (Complex I) or succinate (Complex II) to CoQ.
What carries electrons from Complex I and II to Comlplex III?
Coenzyme Q
Where do electrons from fatty acid oxidation enter electron transport?
At Coenzyme Q
Where do electrons from FADH2 from the glycerophosphate shuttle enter electron transport?
At Coenzyme Q
