Electron Transport and Oxidative Phosphorylation

Electron Transport and Oxidative Phosphorylation
Pyruvate fates depend on O2 conditions
of the cell
Where does O2 come into play?
O2 not required _______________
O2 not required for _____________
O2 is terminal acceptor of _________
_____________________________
How are reducing agents (__________
_____________) used to make ATP?
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Electron Transport and Oxidative Phosphorylation
Production of ATP from reducing agents, NADH/FADH2,
from glycolysis and TCA cycle
Electron Transport
- e- from NADH/FADH2 are
passed along chain of _______
_________________________
- aerobic process, O2 acts
as ____________________
- energy in e- transport used
to pump ________________
_______________________
Oxidative Phosphorylation
- use of the ΔG in H+
_______________________
_______________________
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Electron Transport and Oxidative Phosphorylation
Electron Transport
- NADH/FADH2 are oxidized to NAD+ and FAD
- e- are transferred through a chain
of __________,
- main enzymes are called
___________________
- e- are ultimately accepted by O2
___________________________
- completes process for complete
_______________________
- NAD+ and FAD can be reused
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Electron Transport and Oxidative Phosphorylation
Electron Transport - production of H+ gradient
- _________________ in e- transport chain use
energy of _____________ to pump H+ across inner
membrane to intermembrane space
A.K.A.:
H+ ___________________ gradient, _____ gradient, _________ gradient
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Electron Transport and Oxidative Phosphorylation
Oxidative phosphorylation - ___________________
- energy stored in H+ gradient __________________________
- what other mechanism used energy stored in H+ gradient?
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Electron Transport and Oxidative Phosphorylation
Enzyme complexes of e- transfer
4 enzyme complexes - ____________________________
- Complexes I, III, IV _______________________
- Complex II ____________________________
takes e- from FADH2 and donates to CoQ
Complex II
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Electron Transport and Oxidative Phosphorylation
Enzyme complexes of e- transfer
Complex I - _________________________________
- carries out first step of ___________________
- transfer of e- to Coenzyme Q (CoQ, ubiquinone)
- more than ___________________________
e- transfer
- NADH to flavin ________________________ (FMN)
NADH oxidized to NAD+, FMN reduced to FMNH2
- FMNH2 to _______________
FMNH2 oxidized to FMN, Fe-Soxidized to Fe-Sreduced
- Fe-Sreduced to CoQ
CoQ reduced to
CoQH2
Fe-Sreduced to
Fe-Soxidized
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Electron Transport and Oxidative Phosphorylation
Enzyme complexes of e- transfer
Complex I - NADH-CoQ oxidoreductase
- some H+ moved to intermembrane space, ________________
- e- carries can only transfer, _________________________
- _______________ “pumped” to intermembrane space
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Electron Transport and Oxidative Phosphorylation
Enzyme complexes of e- transfer
Coenzyme Q (ubiquinone) - ______________________ membrane
- _________________________
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Electron Transport and Oxidative Phosphorylation
Enzyme complexes of e- transfer
Complex II - __________________________________________
- second _______ entry point
- carries out e- transfer from _____________________
- ______ subunits
e- transfer
- FADH2 to Fe-S protein
FADH2 oxidized to FAD, Fe-Soxidized to Fe-Sreduced
- Fe-Sreduced to CoQ
Fe-Sreduced to Fe-Soxidized, CoQ to CoQH2
FADH2
FAD+
Complex II
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Electron Transport and Oxidative Phosphorylation
Enzyme complexes of e- transfer
Complex II - Succinate-CoQ oxidoreductase
- FADH2 comes from ____________________________
- complex II reaction weakly
_______________
FADH2
FAD+
- not enough ΔG to
transport __________
__________________
Complex II
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Electron Transport and Oxidative Phosphorylation
Enzyme complexes of e- transfer
Complex III - CoQH2-cytochrome c oxidoreductase, __________________
- transfers e- from CoQH2 through ______________________
- cytochrome: _________ containing protein
- dimer of _______ subunit complexes
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Electron Transport and Oxidative Phosphorylation
Enzyme complexes of e- transfer
Cytochrome - a heme binding protein
- heme similar to O2 binding heme in hemoglobin
and myoglobin
- Cyt heme binds _____________________________
- reduction of ___________________ for e- transfer
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Electron Transport and Oxidative Phosphorylation
Enzyme complexes of e- transfer
Complex III
e- transfer: _______________________________
- CoQH2 releases two e-
- Cyt c can only accept/transfer __________________________
- first e- will be passed to Fe-S protein _____________________
- second e- is passed to Cyt b and cycled back to CoQ
- second e- is then passed on to Cyt c
- energy from reactions transports ________________________
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Electron Transport and Oxidative Phosphorylation
Enzyme complexes of e- transfer
Complex IV - Cytochrome c oxidase
- catalyzes last step of _______________________________
- e- transferred through _________
- Cu ions act as e- transfer intermediates to ______________
- _________ subunits
- energy from reactions transports H+ to intermembrane space
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Electron Transport and Oxidative Phosphorylation
Enzyme complexes of e- transfer
Complex IV - Cytochrome c oxidase
- Cty c is loosely bound to outer _______________________
- can freely move from complex III to IV, transferring eto complex IV
- O2 acts a final ____________________________________
- this is link between O2 and aerobic metabolism
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Electron Transport and Oxidative Phosphorylation
Enzyme complexes of e- transfer
- e- will only flow __________________
- CoQ will not donate ______________
- e- move from high energy to low
energy
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Electron Transport and Oxidative Phosphorylation
Proton gradient formation
1. H+ from NADH in Complex I
2. - proteins of complexes take up H+ from ___________________________
- these H+ are released into intermembrane space
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Electron Transport and Oxidative Phosphorylation
Oxidative phosphorylation
How is the H+ gradient used to produce ATP?
How is chemical energy of H+ gradient converted into
chemical energy of ATP?
ATP synthase - ________________________
energy in H+ gradient
- complex enzyme that ______
________________________
- portions of enzyme found
on _______________
__________________ of
innermembrane
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Electron Transport and Oxidative Phosphorylation
Oxidative phosphorylation
ATP synthase
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Electron Transport and Oxidative Phosphorylation
Oxidative phosphorylation
Chemiosmosis - generation of ATP by _____________________________
across a membrane by ATP synthase
- a.k.a oxidative phosphorylation
F0 = subunit of ATP synthase that acts as an
___________________________________
F1 = subunit of ATP synthase _________________
ATP synthase links the _____________ to the
phosphorylation reaction ____________
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Electron Transport and Oxidative Phosphorylation
Oxidative phosphorylation
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Function of F1 subunit in ATP synthesis
-  three sites for _____________________
-  exist is 3 states:
“O” - open, low binding affinity ____________
“L” - loose-binding of substrate, _________________
“T” - tight-binding of substrate, ________________
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- each binding site can be in one of the states
- movement of H+ through F0 causes conformational change
__________________________________________
1. ATP bound to “T”, __________________________
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2. H+ movement, “T” will change to ________________
“L” changes to “T”
3. “T” forms ________
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Electron Transport and Oxidative Phosphorylation
Oxidative phosphorylation
How is conformational change in F0 accomplished?
- c, γ, ε subunits of F0 and F1
________________________
- H+ movement __________________________
- rotor causes conformational change in
______________________________
ATP Synthase
http://www.youtube.com/watch?v=PjdPTY1wHdQ
Electron transort and ATP synthase
http://www.youtube.com/watch?v=xbJ0nbzt5Kw&feature=related
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Electron Transport and Oxidative Phosphorylation
Glycerol-phosphate shuttle
NADH can not cross the mitochondrial membranes
NADH e- from glycolysis must be carried
Into _____________________________
- DHAP reduced to glycerol
phosphate ___________________
- moved to matrix
- oxidized to DHAP, reducing
________________________
- FADH2 can be used for
H+ gradient formation
- 1.5 ATP from FADH2
- occurs in __________________
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Electron Transport and Oxidative Phosphorylation
Malate-Aspartate shuttle
More complex but more efficient, 2.5 ATP from NADH
- Oxaloacetate reduced to malate in cytosol,
______________________________
- transport to matrix
- oxidation to ___________,
produces NADH
- conversion to aspartate
- transport to cytoplasm
- conversion oxaloacetate
- occurs in _______________
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Electron Transport and Oxidative Phosphorylation
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Electron Transport and Oxidative Phosphorylation
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Electron Transport and Oxidative Phosphorylation
Evolution of mitochondria in Eukaryotic cells
Mitochondria have many similarities to prokaryotic cells (bacteria)
- their own _________________________
- many of the same __________________________
- divide separately from rest of eukaryotic cell, direct their own
division
- have their own _________________________________
Endosymbiosis- early eukaryotic cell form symbiosis with bacteria that could
carry out aerobic metabolism (Krebs cycle, e- transport,
oxidative phos)
Mitochondria were at one time a bacteria that has _________
____________________________________
Chloroplasts in plant cells also
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Electron Transport and Oxidative Phosphorylation
History
Herman Moritz Kalckar - Dutch born biochemist
(1908 -1991)
- worked at University of Copenhagen
- in early 1940’s established link between sugar oxidation
and ATP production
Peter D. Mitchell
(1920 - 1992)
- British biochemist
- worked at Edinburgh University
- 1n 1961 discovered chemiosmosis
as mechanism for ATP production
- 1978 Nobel Prize for Chemistry
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Electron Transport and Oxidative Phosphorylation
History
Paul D. Boyer
(1918 - )
- American born biochemist
- worked at UCLA
- in 1973 discovered conformation binding change
in ATP synthase
- in 1982 proposed rotational catalysis of ATP synthase
John E. Walker
- British born chemist
(1941 - )
- worked at Laboratory of Molecular
Biology of the Medical Research
Council, Cambridge, UK
- determined structure of enzyme in
oxidative phosphorylation
Both awarded Nobel Prize in Chemistry, 1997
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