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37 Cards in this Set

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Glyoxylate Pathway
1. allows plants to generate oxaloacetate from acetyl-CoA
2. shared between glyoxysomes and mitochondria
3. absent in animals
4. does not produce CO2
What drives oxidative phosphorylation?
electron transport
Electron carriers
1. carry electrons from NADH and FADH2 to O2
2. are located in the inner mitochondrial membrane
3. some are mobile and some are relatively immobile as parts of large enzyme complexes
What is the heart of aerobic metabolism?
electron transport system in mitochondria
To what is energy derived from the oxidation of metabolic fuels ultimately converted?
ATP (quick energy currency of the cell)
ETS can be considered a payoff stage in which the reduced cofactors NADH and FADH2 deliver their electrons to...?
ATP
By what is ATP generated?
power of the electron transport across the inner membrane
What role does oxygen play in metabolism?
final acceptor of electrons in the ETS
What is the basis of the ETC?
four closely related enzyme complexes embedded in the inner mitochondrial membrane
What do the electrons do at their final destination?
they combine with molecular oxygen to reduce O2 to 2 H2O
The reverse flow of protons back through the membrane into the inner matrix can be used to do what?
generate ATP
Production of ATP in the mitochondria is the result of what?
oxidative phosphorylation in which ADP is phosphorylated to give ATP
What are the electron carriers in ETS?

-carry electrons from NADH and FADH2 to O2
-are located in the inner mitochondrial membrane
some are mobile and some are relatively immobile as parts of large enzyme complexes
cytochromes, iron sulfur center proteins, coenzyme Q (ubiquinone)
How can we estimate the thermaodynamic efficiency of electron transport?
by inspecting the standard reduction potentials of the redox centers
Does an oxidized substrate's affinity for electrons increase or decrease with its standard reduction potential?
increases
What is an important property of the iron-sulfur cluster?
the oxidized and reduced state may differ by only one charge, regardless of the number of iron atoms in the cluster
CoQ can hold how many electrons?
one or two
How are components with high an dlow oxidation potential allocated along the ETS chain?
strategically
Do the proximal carriers have low or high oxidation?
low oxidation
high reducing (as the chain moves toward oxygen)
What do complexes I, II and III have in common?
they have iron sulfur centers with low oxidation potential
What do you call Complex I?
NADH-Coenzyme Q Oxidoreductase
what do you call Complex II?
Succinate-CoQ Oxidoreductase
What does NADH-Coenzyme Q Oxidoreductase do?
passes electrons from NADH+ to coenzyme Q (ubiquinone)
Is CoQ polar or nonpolar?
highly nonpolar, loves the membrane environment
Cytochromes
-electron-transport heme proteins
-heme groups contain iron that alternates between Fe+2 and Fe+3
-iron ion in heme is surrounded by a planar porphyrin system
-have characteristic absorbance spectra
-can transfer electrons over 10-20 A
What do you call Complex III?
CoQ-Cytochrome c Oxidoreducatase
In Complex III where do electrons enter and exit?
Enter: CoQH2
Exit: cytochrome c1
How many cytochromes and iron-sulfur proteins does Complex III contain?
3 cytochromes and 1 iron-sulfur protein
(two of the cytochromes are part of the system that pumps protons from one side to the other
What are the inhibitors of Complex I? (RAM)
Rotenone, amytal, mercurial compounds
What are the inhibitors of Complex II? (TC)
Thenoyltrifluroacetone, carboxin
What are the inhibitors of Complex III? (AM)
Animycin, myxothiazol
What are the inhibitors of Complex IV? (CAC)
Cyanide, Azide, Carbon monoxide
What do you call Complex IV?
Cytochrome c Oxidase or

"Cytochrome Oxidase"
Which of the four enzymes functions singulary?
Complex IV
Does Complex IV have an iron-sulfur center protein?
no
What is the only complex that comes in direct contact with O2?
Complex IV
What is the major event in the reduction of oxygen to water?
activating dioxygen