Biological Oxidation Flashcards
The outer membrane of mitochondria have pores that make it permeable to small molecules and ions, but not proteins. True or false?
true
The inner membrane of a single liver mitochondria may have more than ___ sets of electron-transfer systems and ATP synthase molecules
10K
The heart muscle mitochondria contains __ X more electron transfer systems than liver mitochondria
3
Muscle and liver mitochondria are about the size of a bacterium __-__ um long
1-2
Each complex in the ETC contains multiple ___ centers
redox
Coenzyme Q is a mobile electron carrier transporting electrons from complexes ___ and ___ to complex __
1; 2; 3
Cytochrome c is the second mobile electron carrier. It carries a single electron from the cytochrome ___ complex to cytochrome ___
bc1; oxidase
What is the name for complex I and what does it do?
NADH-UQ oxidoreductase: catalyzes transfer of e- from NADH to UQ or CoQ
What is the name for complex II and what does it do?
succinate-ubiquinone oxidoreductase or succinate dh: transfers e- from succinate to CoQ
What is the name for complex III and what does it do?
cytochrome bC1 complex: transfers e- from ubiqunol
What is the name for complex IV and what does it do?
cytochrome c oxidase: transfers e- from cytochrome c to O2
What is the name for Complex V and what does it do?
ATP synthase: uses energy of the electrochemical gradient for synthesis of ATP
For the following compound, give its target/mode of action towards inhibiting the ETC:
cyanide, carbon monoxide
inhibit cytochrome oxidase
For the following compound, give its target/mode of action towards inhibiting the ETC:
Antimycin A
blocks electron transfer from cytochrome b to cytochrome c
For the following compound, give its target/mode of action towards inhibiting the ETC:
myxothiazol, rotenone, amytal, piercidin A
prevent electron transfer from Fe-S center to ubiquinone
For the following compound, give its target/mode of action towards inhibiting the ETC:
DCMU
competes with Q for binding site in PSII
For the following compound, give its target/mode of action towards inhibition of ATP synthase:
Aurovertin
inhibits F1
For the following compound, give its target/mode of action towards inhibition of ATP synthase:
Oligomycin, Venturicidin
inhibits F0 and CF0
For the following compound, give its target/mode of action towards inhibition of ATP synthase:
DCCD
blocks proton flow through F0 and CF0
For the following compound, give its target/mode of action towards inhibition of ATP-ADP exchange:
atractyloside
inhibits adenine nucleotide translocase
Complex I catalyzes the transfer of a hydride ion from ___ to ___, from which 2e- pass through a series of Fe-S centers to the Fe-S center N-2
NADH; FMN
Complex I is one of the largest macro-molecular assemblies in the mammalian cell with over ___ different polypeptide chains, encoded by both nuclear and mitochondrial genes
40
Succinate DH (complex II) has ABCD subunits. Succinate binds to subunit A just behind the ___
FAD
In regards to succinate DH, subunit B has three Fe-S centers, ____ is bound to subunit B, and ___ b is sandwiched between subunits C and D
ubiquinone; heme
In reagards to succinate DH, electrons move from succinate to FAD, then through the three Fe-S centers to ubiquinone. FAD accepts ___ electrons from succinate. Electrons pass one at a time via __-__ centers to Q, which becomes reduced QH2
2; Fe-S
Does succinate DH (complex II) transport protons?
no
In regards to complex III, ubiquinone: cytochrome c oxidoreductase, the complex has two distinct binding sites for ubiquinone, Qn and Qp, which correspond to sites of what?
sites of inhibition by two drugs that block oxidative phosphorylation
In regards to complex III, ubiquinone: cytochrome c oxidoreductase, Antimycin A blocks electron flow from ___ __ to ___, binds at ___
heme bh; Q; Qn
In regards to complex III, Myxothiazol prevents electron flow from ___ to the ___ __–__ protein, binds at ___
QH2; Rieske iron-sulfur; Qp
In regards to complex III, the ___ structure is essential to function. The interface between monomers forms two caverns, each containing a Qp site from one monomer and a Qn site from the other.
dimeric
Electron transfer through complex IV begins with cytochrome C, Two molecules of reduced cytochrome c donate an electron to the binuclear center ___
Cua
In regards to complex IV, after electrons are donated to Cua, they pass through heme __ to the Fe-Cu center. Delivery of two more electrons from cytochrome c converts the ___ to two molecules of water, with use of 4 substrate protons from the matrix
a; O2
note: at the same time, 4 protons are pumped from the matrix
In summary of the ETC, electrons reach Q through complex __ and ___. The reduced Q (___) serves as a mobile carrier of electrons an protons.
I; II; QH2
In summary of the ETC, electrons are passed to complex III which passes them to another mobile connecting link, ____ __. Complex IV then transfers electrons from reduced cytochrome C to ___
cytochrome C; O2
In summary of the ETC, Complexes I, III, and IV are accompanied by ___ flow from the matrix to the inter membrane space
proton
Ubiquinol diffuses freely in the membrane and is oxidized by complex ___
III
2 electrons from NADH to O2 result in the translocation of 10 protons across the membrane Thus, for each pair of electrons transferred to O2, there are ___ from complex I, ___ from complex II, and ___ from complex IV
4; 4; 2
