Term
| oxidative phosphorylation |
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Definition
1. a way of taking the protons and electrons that have been harvested to generate ATP
2. Protein strucutre is critical
3. side chains play a major role |
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Term
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Definition
1. 70 kg person needs about 8400 kj/day of energy
2. translates to 83 kg of ATP/day
3. Body has 250g of ATP at any given moment
4. ATP is generated from ADP and Pi approx. 300x/day |
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Term
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Definition
1. organelle where ATP regeneration happens
2. outer membrane--highly permeable to small molecules, hardly discussed in ATP regeneration
3. inner membrane--highly impermeable, bilayer primarily discussed for ATP regenration
4. intermembrane space (IMS)-space between inner and outer membrane
5. cristae--inner membrane invaginations into the matrix
6. matrix--space inside mitochondria |
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Term
| 2 componenets to ATP generation |
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Definition
1. NADH and FADH2 harvested are used to pump protons into the intermembrane space, leaving electrons in the matrix. (matrix becomes negative, IMS becomes positive)
2. Chemioosmotic hypothesis for making ATP |
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Term
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Definition
1. composed of complexes 1-4
2. Regenerates NAD+ and FAD
3. pumps protons into the IMS
4. transfers electrons to the final acceptor, oxygen (aerobic respiration) |
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Term
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Definition
1. Name: NADH-Q oxidoreductase
2. consumes NADH from krebs cycle and glycolysis and pumps protons into the intermembrane space
3.NADH gives 2 e- to FMN, a coenzyme in complex 1, fully reducing FMN.
4. the elctrons travel through a series of Fe-S clusters and are passed to co-enzyme Q.
5. Coenzyme Q takes 2 protons along with the electrons and becomes QH2 (fully reduced).
6. 4 protons are pumped into the IMS |
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Term
| why do prokaryotes produce more ATP than eukaryotes? |
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Definition
| Eukaryotes consume ATP when they transfer NADH from the cytosol into the matrix of the mitochondira, whereas prokaryotes do not have this energy requiring step in their metabolism due to everything happening in the cytoplasm |
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Term
| describe the energy situation surrounding the production of QH2 |
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Definition
| generation of QH2 is highly exergonic, very favorable; in the process it pumps 4 protons into the intermembrane space |
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Term
| net result of complex 1 (NADH-Q oxidoreductase) |
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Definition
| NADH + Q + 5H+----> NAD(+) + QH2 + 4H-(IMS) |
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Term
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Definition
1. HUGE!--900kd and 46 sub-units, largest protein complex involved in respiration in bacteria and mitochondria
2. structure suggests favorable (coordinated catalysis) process of transferring protons to CoQ
3. Results in piston shunting mechanism that drives the 4H+ across inner membrane through 3 separate channels |
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Term
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Definition
1. enzyme name-succinate-Q reductase (same enzyme that was involved in converting succinate to fumarate). FADH2 and FAD are bound in the enzyme complex.
2. FADH2 directly transfers 2 protons and 2 e-'s to Q
3. FAD is regenerated
4. It's another starting point in the ETC that links ETC directly to the citric acid cycle, its not a part of the NADH pathway
5. Generates 1 QH2, but no protons are pumped into the gradient during this step. This is why FADH only generates 1.5 ATP |
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Term
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Definition
1. Q/QH2 is a molecule that is readily soluble in the hydrophobic bilayer due to a superlong CH3 tail.
2. It can travel from complex to complex and exists as a pool around the complexes in order to mediate the ETC complexes |
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Term
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Definition
1. oxidized Q--Q or Ubiquinone
2. reduced Q--QH2 or ubiquinol (accepted 2 electrons and 2 protons)
3. QH and 1 electron
4. Q with a formal negative charge (lost one proton, but has 1 electron) |
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Term
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Definition
1. enzyme name--Q-cytochrome C oxidoreductase
2. Has three binding sites: Q initial (1) where Q binds; Q naught (0) where QH2 binds, and a cytochrome C oxidized binding site |
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Term
| Complex 3 mechanism--Part 1 |
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Definition
1. A QH2 molecule, bound to the Qo site, transfers 1 electron to CytC1
2. CytC1 transfers the electron to Cyt C ox, yielding Cyt C red
3. Cyt C red travels to complex 4
4. The other electron on QH2 travels to Q bound at site Q1, yielding Q- (Formal negative charge)
5. The two protons on QH2 are pumped into the IMS
6. The newly formd Q, bound to Qom enters the Q pool |
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Term
| complex 3 mechanism--part 2 |
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Definition
7. A second QH2 binds to the Qo site
8. One electron travels to CytC1 then to CytCox--> Cyt C red
9. The other electron is transferred to the Q- (semiquinone radical) bound to Q1
10. The Q2- uptakes 2 protons from the matrix becoming QH2
11. This QH2 enters the Q pool, opening Q1 for another reaction
12. The two protons on the QH2 that was bound to the Qo site are pumped into the IMS |
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Term
| net result of complex 3 mechanism |
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Definition
| 2 QH2 + Q + 2 Cyt Cox + 2H+(matrix) ---> 2Q + QH2 + 2Cyt C red +4H+(IMS) |
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Term
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Definition
enzyme name--Cytochrome C oxidase
1. mechanism requires 4 electrons, or 4 Cyt C red molecules, which means you have to double all the previous steps. Essentially, you consume 2 NADH and 2 FADH2, pump out 16 protons, and consume 4 protons to regenerate 2 QH2 |
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Term
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Definition
1. 2 Cyt Cred will bind consecutively
2. The 2 electrons will travel through coppe and heme clusters, finally arriving at Heme a3 and Cub, which are both reducing molecules (oxygen enters here)
3. The two reduced molecules bind to a single molecule of O2 forming a peroxide bridge
4. Two more Cyt Cred will bind the complex and break the peroxide bridge by transferring their electrons
5. Two protons enter from the matrix
6. This forms CU2b-OH and Heme a3-OH
7. Two more H+ will enter from the matrix forming H2O molecules that release from complex 4
8. 4 H+ protons are pumped into the IMS |
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Term
| net reaction in complex 4 |
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Definition
| 4 Cyt Cred + 8 H+(matrix) + O2--> 4 Cyt Cox + 2 H2O + 4H+(IMS) |
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Term
| describe the energy of generating H2O |
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Definition
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Term
| what is the overall result of the ETC |
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Definition
| By pumping protons out, we create a more negative matrix, and a more positive IMS |
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Term
| who figured out what re-generated ATP |
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Definition
| Paul Mitchell--proposed the chemiosmotic hypothesis where ETC and ATP synthesis are coupled to a proton gradient across the inner mitochondrial membrane |
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Term
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Definition
| composed of a ball (F1) and stick (Fo) sub-units |
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Term
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Definition
1. a hexameric ring that extends into the matrix composed of alternating a3 and B3 subunits
2. a long, helical rotating y sub-unit that extends into the hexameric ring
3. stationary delta and rotating epsillon subunits |
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Term
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Definition
1. 10-14 rotating c sub-units, embedded in the membrane
2. the stationary A sub-unit contact 2 c units at a time |
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Term
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Definition
1. a sub-unit of the the Fo is attached via the b2 sub-unit to the delta subunit of F1
2. the gamma and epsillon sub-units interact with the c sub-units |
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Term
| alpha3 and beta3 subunits |
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Definition
1. part of the hexameric ring
2. both bind nucleotides
3. only the Beta units perform catalysis
4. gamma sub-unit extens into the ring and breaks symmetry of alpha3-Beta3 hexamer, with each beta sub-unit interacting with the gamma sub-unit |
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Term
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Definition
| Stationary, they bind ATP and stop |
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Term
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Definition
1. change position based on their interactions with gamma subunit as it rotates
2. will either be in open --> loose --> tight conformation
3. The gamma sub-unit generates 1 ATP for every 120 degree rotation |
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Term
| open, loose, tight conformation |
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Definition
1. open--nothing bound
2. loose--ADP and Pi are bound
3. tight--physically and mechanically squeezes together ADP and Pi to form ATP |
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Term
| c sub-unit and alpha sub-unit structures |
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Definition
1. flow of protons through Fo sub-unit powers rotation of the gamma unit
2. a single c-subunit is made of two alpha helices with an aspartic acid residue that spans them, and carries a negative charge
3. staionary alpha-sub-unit has 2 half channels. One channels connects to proton rich IMS, other connects to matrix which is proton porr. Has a positively charged surface |
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Term
| flow of protons through c sub-units |
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Definition
1. 2 C-sub-units interact with the alpha-sub-unit via the negatively charged aspartic acid on the c-sub-unit; and the + charged surface of the alpha sub-unit
2. A proton enters the IMS alpha sub-unit half channel and interacts with the aspartic acid, giving it a neutral charge
3. The c sub-unit no longer wants to interact with th + charged alpha-sub-unit surface due to its neutral charge. It wants to interact with the hydrophobic bilayer of the innermembrane.
4. This causes the C sub-unit to rotate over by one C-sub-unit, and interact with the hydrophobic bilayer. A previously neutralized aspartic acid, bound to a proton, will move into position over the matrix-side half channel.
5. The proton will dissociate from the aspartic residue and into the matrix. This is a favorable movement because the proton is exposed and attracted to the negatively charged matrix
6. The aspartic acid that just lost a proton returns to its negatively charged state, and is ready to bind another proton as it is now exposed to the IMS half-channel. |
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Term
| How does the movement of protons power ATP formation? |
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Definition
1. the gamm and epsilon sub-units are tightly linked to the c ring
2. as the c ring rotates it rotates the gamma and epsilon sub-units
3. the alpha and beta sub-units are held tight by the delta sub-unit
4. As the gamma sub-unit rotates to each individual Beta unit, it changes conformation, generating an ATP |
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Term
| transporters needed to mediate substrate traffic |
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Definition
| NADH from glycolysis, ADP, HPO4- (source of Pi) |
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Term
| How does NADH from glycolysis get to ETC in muscle cells? |
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Definition
1. shuttled into the matrix via the glycerol-3-phosphate shuttle
2. DHAP, which is at 96%, generates glycerol-3-phosphate, using an NADH and another proton
3. Glycerol 3-phosphate enters the ETC in the FADH2 step
4. This is also why an NADH from glycolysis will generate less ATP than an NADH from the TCA cycle. An NADH from glycolysis will only generate 1.5 ATP, whereas a Krebs cycle NADH will generate 2.5 ATP. |
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Term
| How does NADH from glycolysis get to the ETC in heart and liver cells? |
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Definition
1. malate-aspartate shuttle
2. heart and liver cells needs as much ATP as they can possibly get
3. NADH is transported into the matrix as malate
4. Malate releases NADH
5. NADH is consumed by complex 1
6. This results in the heart and liver cells generating the full 2.5 ATP per NADH molecule (As opposed to the muscle cells which only got 1.5 ATP form their glycolysis NADH). |
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Term
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Definition
1. The ATP-ADP translocase mediates a 1:1 transfer
2. comprises 15% of the total protein present in the inner membrane
3. Since ATP is negatively charged its transport out of the matrix is favored
4. Great way of coupling the exchange of ADP into the matrix when more ATP is needed |
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Term
| transporter for OH- and phosphate |
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Definition
| Transporter for OH- and phosphate |
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