Oxidative Phosphorylation (Chapter 11.3-11.5 Slides 38-66) Flashcards
Each ATP synthase complex has ______ α and ______ β subunits
3, 3
The bacterial ATP synthase complex contains a subunit called ______ that associates with the F1 component.
ε
The ______ subunit of the yeast ATP synthase complex is homologous to the bacterial ε subunit.
δ
What are the three functional components of the ATP synthase complex?
rotor, stator, headpiece
The ______ holds the headpiece in place so that it does not turn with the rotor
stator
The ______subunits of the headpiece contain the ______ sites for ATP synthesis, and the ______ is responsible for translating proton-motive force into protein conformational changes in the headpiece.
β, catalytic, rotor
True or False: The same three functional components are found in all ATP synthase complexes.
True
True or False: When one β subunit is in the Lconformation, the other two can be in either L, T or O conformations.
False, the other two must be in the T and O conformations.
The yeast mitochondrial ATP synthase complex appears to require ∼______H+ for each ATP synthesized.
3
True or False: The number of H+ required for each 120° turn of the γ subunit depends on the number of subunits in the c ring.
True
What was the first experiement to demonstrate rotational movement in the ATPase
Yoshida and Kinosita
______ drives the γ-subunit rotation in the clockwise direction
ATP hydrolysis
ATP ______ results in the conformational sequence O → T → L → O for a given β subunit, which is opposite that of ATP ______.
Hydrolysis, synthesis
______ can be used as a nanomotor to drive ATP ______
F1, synthesis
The ______ model proposes that protons drive rotation of the c ring in response to the electrochemical proton gradient, through alternate protonation and deprotonation of a charged Asp residue in each c subunit
two channel
True or False: In the two-channel model, the electrochemical proton gradient drives rotation of the c ring as protons move from the intermembrane space into the mitochondrial matrix through two half-channels in the a subunit.
True
True or False: The mitochondria inner membrane allows ions to pass through.
False, impervious to ions to allow formation of a proton gradient
True or False: Biomolecules required for the electron transport system or oxidative phosphorylation must be transported across the mitochondrial inner membrane
True
WHat two translocases transport ATP, ADP, and Pi?
ATP/ADP translocase
phosphate translocase
What two systems transfer electrons to the matrix?
malate-aspartate shuttle
glycerol-3-phosphate shuttle
True or False: The C state of the mitochondrial ATP/ADP translocase faces toward the ______ and the M state faces toward the ______.
Intermembrane space, mitochondrial matrix
Atractyloside blocks the ______ state and bongkrekic acid block the ______ state.
C, M
Phosphate translocase functions as a ______ when is translocates H2PO4− (Pi) and H+P across the membrane
Phosphate translocase functions as a ______ that exchanges H2PO4− for OH−.
Symporter, antiporter
True or False: In both cases, the movement of H2PO4− into the mitochondrial matrix is electrically neutral.
True
The flow of _______ H+ into the mitochondrial matrix is required for every ATP synthesized.
4 (1 from phosphate translocase, 3 from ATP synthase complex)
The malate–aspartate shuttle moves a pair of electrons from ______ NADH to ______ NAD+.
cytosolic, mitochondrial
What are the four key steps to the malate–aspartate shuttle in liver cells?
Reduction of oxaloacetate in the cytosol with NADH + H+ by the enzyme cytosolic malate dehydrogenase to malate and NAD+.
Malate is transported in to the mitochondrial matrix and oxidized by the mitochondrial malate dehydrogenase with NAD+ to form oxaloacetate and NADH + H+.
Transamination of oxaloacetate by mitochondrial aspartate aminotransferase and glutamate to form α-ketoglutarate and aspartate, which is shuttled across the membrane.
Deamination of aspartate in the cytosol by cytosolic aspartate aminotransferase and α-ketoglutarate to form oxaloacetate and glutamate.
What are the three steps in the glycerol-3-phosphate shuttle?
Reduction of the glycolytic intermediate dihydroxyacetone phosphate in the cytosol, forming glycerol-3-phosphate. The glycerol-3-phosphate then diffuses across the outer mitochondrial membrane through porin channels.
Once in the intermembrane space, the glycerol-3-phosphate is reoxidized to form dihydroxyacetone phosphate. In the process, 2 e− are transferred to an FAD moiety in mitochondrial glycerol-3-phosphate dehydrogenase. (The regenerated dihydroxyacetone phosphate recycles back to the cytoplasm through other porin channels.)
The 2 e− are then passed to Q, which transfers them one at a time to complex III via the Q cycle (see Figures 11.8 and 11.18).
True or False: Numerous enzymes in glycolysis and the citrate cycle are regulated by intracellular concentrations of ATP, ADP, AMP, Pi, NAD+, and NADH.
True
True or False: The chemical uncouplers 2,4-dinitrophenol (DNP) and carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP) activate proton diffusion down the electrochemical proton gradient, which decreases the efficiency of oxidative phosphorylation.
True
True or False: Decreased expression of uncoupling protein 1 (UCP1) in brown adipose tissue short-circuits the electrochemical proton gradient and diverts redox energy to heat production.
False, increased
High levels of ______ give brown adipose tissue its dark color
Mitochondria
True or False: The majority of cytosolic space in white adipose tissue is filled with large fat droplets
True
Mitochondrial diseases such as LHON are ______ inherited
Maternally
LHON and MELAS are associated with what complex?
I
NARP, MILS FBSN are associated with what complex?
ATP synthase
Sporadic anemia is associated with what complex?
IV
