Term
| external electron acceptor |
|
Definition
| with an____ available, complete oxidation of substrates to CO2 becomes possible, and ATP yields are much higher |
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Term
| "external" electron exceptor meaning |
|
Definition
| not a by-product of glucose catabolism |
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|
Term
| the by products are not completely oxidized to CO2 |
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Definition
| when an internal electron acceptor such as pyruvate or acetaldehyde is used to accept electrons from NADH |
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Term
|
Definition
| the flow of electrons, through or within a membrane, from reduced coenzymes to an external electron acceptor, usually accompanied by the generation of ATP |
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Term
|
Definition
| reduced coenzyme generated by the glycolytic catabolism of sugars or related compounds |
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Term
|
Definition
| also collect the electrons that are removed from oxidizable organic substrates and pass them to the terminal electron acceptor via a series of electron cariers, generating ATP in the process |
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Term
|
Definition
| overall process in which the terminal electron accetor is oxygen, the reduced form of this terminal electron acceptor is water |
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Term
|
Definition
| organelle where most aerobic ATP production in eukaryotic cells takes place |
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Term
|
Definition
| with oxygen available as the terminal electron accpetor, ____ can be oxidized completely to CO2 instead of being used to accept electrons from ___ |
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Term
|
Definition
| aerobic respiration has the potential of generating up to ___ per glucose |
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|
Term
cytosol with glycolysis
pyruvate |
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Definition
| oxidation of glucose and other sugars begins in the _____, producing |
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Term
|
Definition
| after being oxidized from glucose, pyruvate is transported across the inner mitochondrial membrane and is oxidized within the matrix to___ which enters the____ |
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Term
|
Definition
| primary substrate of the TCA cycle |
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Term
| beta oxidation of fatty acids |
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Definition
| acetyl CoA can also be formed by this process |
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|
Term
| energy of the proton gradient |
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Definition
| the ___ is used to drive the synthesis of ATP from ADP and inorganic phosphate |
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Term
|
Definition
| involves oxidative pathways in which electrons are removed from organic substrates and transferred to coenzyme carriers, which then transfer these electrons to oxygen, accompanied indirectly by the generation of ATP |
|
|
Term
| substrate oxidation and simultaneos reduction of coenzymes |
|
Definition
| first three stages of aerobic respiration involve this |
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|
Term
| coenzyme reoxidation and generation of ATP |
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Definition
| second two stages of aerobic respiration |
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Term
|
Definition
| transfer of electrons from reduced coenzymes to oxygen, coupled to the active transport of protons across a membrane |
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Term
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Definition
| the TCA cycle completely oxidizes acetyle CoA to ___ and conserves most of the energy as high-energy reduced coenzyme molecules |
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|
Term
| electrochemical proton gradient |
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Definition
| transfer of electrons from coenzymes to oxygen generates____ across the membrane |
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|
Term
| oxidative phosphorylation |
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Definition
| energy of proton gradient is used to drive ATP synthesis in process known as____ |
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|
Term
| chemotrophic and phototrophic |
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Definition
| mitochondria are present in both ___ and ___ cells are are found not only in animals but also plants |
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Term
| outer membrane of mitochrondrion |
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Definition
| not a significatn permeability barrier for ions and small molecules because it contains ransmembrane channel proteins called porins that permit the passage of solutes with molecular weight up to about 5000 |
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Term
|
Definition
| is continuous with the cytosol with respect to small solute. this is because porins of the outer membrane allow the free movement of small molecules across the outer membrane |
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Term
| enzymes and other soluble proteins are too large to pass throught the porin channels |
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Definition
| enzymes targeted to the intermembrane space are effectively confined there because |
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Term
|
Definition
| presents permeability barrier to most solutes, thereby partitioning the mitochondrion into two separate compartments |
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|
Term
| intermembrane space and the mitochondrial matrix |
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Definition
| two compartments of the mitochondrion |
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|
Term
| where the membranes are in contact |
|
Definition
| regions that proteins destined for the mitochondrial matrix pass through the two membranes |
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|
Term
|
Definition
| distinctive infoldings that greatly increase mitochondria surface area; may be tubular structures that associate in layers to form lamellar ___ of irregular size and shape |
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Term
|
Definition
the inner membrane is about 75% ___ weight which is a higher proportion than in any other cellular membrane |
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|
Term
solute transport, electron transport, and ATP synthesis |
|
Definition
proteins in the inner membrane include ones that are involved in ___, ___, and ____ |
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Term
|
Definition
| where protons can accumulate between the folded inner membranes during hte electron transport process |
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Term
|
Definition
| cristae hae only limited connections to the inner boundary membrane through small tubular openings known as ___ that effectively limit diffusion of materials between the intracristal space and the intermembrane spaece, effectively creating a third, nearly enclosed region in the mitochondrion |
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Term
|
Definition
| high respiratory activity = ___ |
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|
Term
|
Definition
| fluid in mitochondria that in filled with enzymes involved in mitochondrial funciton as well as DNA molecules and ribosomes |
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Term
|
Definition
| knoblike spheres that are involved in ATP synthesis that protude from the innermembrae into the matrix are an assembly of several different polypeptides |
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Term
|
Definition
metabolic functions:
phospholipid synthesis
fatty acid elongation
fatty acid denaturation |
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|
Term
|
Definition
metabolic functions:
electron transport
oxidative phosphorylation
pyruvate import
fatty acyl CoA import
metabolite transport |
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|
Term
|
Definition
pyruvate oxidation
TCA cycle
beta oxidation of fats
DNA replication
RNA synthesis (transcription)
protein synthesis (translation) |
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Term
|
Definition
| short protein stalk that each F1 complex is attached to. it's an assembly of hydrophobic polypeptides that are embedded within the mitochondrial inner membrae or in the plasma membrane of bacteria |
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Term
|
Definition
| F1 linked to Fo regarded as ___ because that is its normal role in energy metabolism; responsible for most ATP generation that occurs in mitochondria and bacterial cells |
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Term
|
Definition
| do not have mitochondria but are capable of aerobic respiration |
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|
Term
| cytoplasm and plasma membrane |
|
Definition
| perform the same functions as the mitochondiral matrix and inner membrane, respectively |
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|
Term
cytoplasm
plasma membrane |
|
Definition
in bacteria, most enzymes of the TCA cycle are found in
electron transport proteins are located in the |
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Term
|
Definition
| involves cyclic pathway that that is central feature of energy metabolism in almost all aerobic chemotrophs |
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Term
|
Definition
| important intermediate pyruvate oxidation. has three carboxylic acid groups and is therefor a tricarboxlic acid. this is why the pathway is called TCA or Krebs cycle |
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|
Term
|
Definition
| TCA cycle metabolizes ___, a compound produced from pyruvate decarboxyliation |
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Term
|
Definition
| arises either by oxidative decarbodlation of pyruvate or the oxidative breakdown of fatty acids |
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|
Term
acetyl CoA, oxidized coenzymes, ADP and P1
CO2, reduced coenzymes and one molecule of ATP |
|
Definition
substrates for the TCA cycle
products of the TCA cycle |
|
|
Term
| pyruvate dehydrogenase complex |
|
Definition
| converts pyruvate into acetyl CoA |
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Term
|
Definition
| B vitamin that ACoA contains |
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Term
|
Definition
| with each round of the TCA cycle, two carbons enter as ___, and two carbons leave as ____ |
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Term
|
Definition
| ___ of the eight steps in the TCA cycle are oxidations |
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Term
|
Definition
| step of TCA cycle where ATP is generated from the oxidation of GTP |
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Term
|
Definition
| maximum energy yield in ATPs for NADH and FADH2 respectively |
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|
Term
| glucose + 10NAD+ +2FAD + 4ADP+4P yields 6CO2 + 10NADH + 2FADH2 + 4ATP |
|
Definition
| reaction for entire sequence from glucos throught the TCA cycle |
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Term
|
Definition
| most of the control of the TCA cycle involves ____ of four key enzymes by specific effector molecules that bind irreversibly to them |
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|
Term
|
Definition
| TCA cyle is highly sensitive to ___ and ___ of the cell |
|
|
Term
CoA, NAD, AMP, and ADP
acetyl CoA, NADH, ATP and succinyl CoA |
|
Definition
allosteric regulators
inhibitors |
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|
Term
| mitochondria and peroxisomes; cytoplasm |
|
Definition
| where beta oxidation occurs in eukarotyes and where it occurs in bacteria |
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Term
|
Definition
| process of fatty acid catabolism to acetyl CoA. called this because the oxidative events in each cyle occur on the carbon atom in the beta position of the fatty acid |
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|
Term
| oxidation, hydration, reoxidation, and thiolysis |
|
Definition
| each cyle of beta oxidation pathway includes the same four steps: |
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|
Term
| FADH2, NADH, and acetyl CoA |
|
Definition
| products of beta cycle as the fatty acid is shortened by two carbons in each cycle |
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Term
|
Definition
| activation stpe that occurs in the cytosol |
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Term
|
Definition
| excessive fat breakdown can deplete free CoA and lead to condition known as ___, in which fats cannot be oxidized completely to CO2, and partial oxidation produces known as ketone bodies are formed. can lower the pH of blood |
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Term
|
Definition
| hydrolysis of the peptide bonds that link amino acids together. what protein catabolism begins with. |
|
|
Term
| pyruvate, acetyl CoA, key intermediates |
|
Definition
| dispide their number and chemical diversity, all the pathways for amino acid catabolism eventually lead to ____, ____, or ____ in the TCA cycle |
|
|
Term
| alanine, aspartate, and glutamate |
|
Definition
| can be converted directly to pyruvate, oxaloacetate, and alpha-ketoglutarate. all other amino acids require more complicated pathways. |
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Term
|
Definition
| TCA cycle referred to as ____ because it's a cetnral link between catabolic and anabolic pathways |
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Term
|
Definition
| converts acetyl CoA to carbohydrates and specifically occurs in fat-storing plant seeds that must convert this fat to sucrose |
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|
Term
| glycolysis, pyruvate oxidation, and TCA cycle |
|
Definition
| first three stages of aerobic respiration |
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Term
|
Definition
| large amounts of free energy is release when these reduced coenzymes are reoxidized by transfer of their electrons to molecular oxygen; almost about 90% of the potential free energy present in glucose molecule is conserved in _____ that are formed when a molecule of glucose is oxidized to CO2 |
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|
Term
|
Definition
| fourth stage of respiratory metabolism which involves the oxidation of NADH and FADH2 with oxygen as the terminal electron acceptor. accounts not only for reoxidation of coenzymes and the consumption of oxygen but also for the formation of water which is reduced form of oxygen and along with CO2, one of the two end producys to aerobic energy metabolsim |
|
|
Term
| electron transport system |
|
Definition
| contains a number of integral membrane proteins that are found int he inner mitochondrial membrane of eukaryotes (or the plasma membrane of bacteria) |
|
|
Term
| flavoproteins, iron-sulfur proteins, cytochromes, copper-containing cytochromes, coenzyme Q |
|
Definition
| hydrophobic (because most of it takes place in the membrane) carriers that make up the ETS. |
|
|
Term
|
Definition
| all carriers are proteins with specific prosthetic groups capbable of being reversibly oxidized and reduced except ____ |
|
|
Term
| standard reduction potential E0' |
|
Definition
| measure in volts of the affinity a compound has for electrons. descrives how easily a compound iwll gain electrons and become reduced |
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|
Term
|
Definition
| reduction potentials are determined experimentally for a ____, which consists of two molecules or ions tha tare interconvertible by the loss or gain of electrons |
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|
Term
|
Definition
| allow us to compare redox pairs and to predict the direction electrons iwll tend to flow when several redox pairs are present in the same system, as in the case for the electron transport system |
|
|
Term
positive E0'
negative E0' |
|
Definition
oxidized form has high affinity for electrons and is therefore a good electron acceptor
measure of how good an electron donor in the reduced for of a redox pair is; but means that it is a poor electron acceptor |
|
|
Term
|
Definition
| under standard conditions, the reduced form of any redox pair will spontaneously reduce the oxidized form of any pair below/above it on the table |
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|
Term
|
Definition
|
|
Term
|
Definition
| measure of thermodynamic spontaneity for the redox reaciton between any two redox pairs under standard conditions |
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|
Term
| electron transport system |
|
Definition
| the difference in reduction potentials between the NAD/NADH and O2/H20 redox pairs drives the ____ and creates a proton gradient whose electrochemical potential will drive ATP synthesis |
|
|
Term
|
Definition
| most electron carriers in the ETS are thought to be organized within the inner mitochondiral membrane into four different kinds of ____ which consists of a distinctive assembly of polypeptides and prothetic groups and each complex has aunique role to play in the electron transport process |
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Term
|
Definition
| transfers electrons for NADH to coenzyme Q |
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|
Term
|
Definition
| transfers to CoQ the electrons derived from succinate in reaction TCA 6 |
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|
Term
|
Definition
| accepts electrons from coenzyme Q and passes them to cytochrome c |
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|
Term
|
Definition
| transfers electrons from cytochrome c to oxygen |
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|
Term
|
Definition
| four each pair of electrons transported through complexes I, III, and IV, ___ are pumped from the matrix into the intermembrane space |
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|
Term
|
Definition
| uses the energy from the proton gradient generated during electron transport to synthesize ATP from ADP and P |
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|
Term
|
Definition
| transferring electrons directly to oxygen. cytochrom c oxidase is one of these and is therefore a critical link between aerobic respiratin and the oxygen that makes it all possible |
|
|
Term
|
Definition
| respiratory complexes are not lined up in the membrane in the orderly fashion often seen in textbook diagrams but exist in the membrane as mobile complexes because the inner mitochondrial membrane has a high ratio of unsaturated to saturated phospholipids and virtually no cholesterol, so its fluidity is very high and the mobility of the respiratory complexes is correspondingly high |
|
|
Term
|
Definition
| supercomplexes that multiprotein respiratory complexes are organized into which contain several individual respiratory complexes associated in defined ratios. they minimize diffusion distances, facilitating electron flow between the respiratory complexes |
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|
Term
|
Definition
| links the ETS to the dehydrogenation (oxidation) reactions of the TCA cycle and to most other oxidation reactions in the matrix of the mitochondrion |
|
|
Term
| coenzyme Q and cytochrome C |
|
Definition
| ____ and ____ are both relatively small molecules that can diffuse rapidly, either within the membrane or on the membrane surface respectively. because of their abundance and mobility, they are able to transfer electrons between the major complexes frequently enough to account for the observed rates of electron transfer in activley repsiring mitochondria |
|
|
Term
| NADH, coenzyme Q, and cyochrome c |
|
Definition
| key intermediates in the electron transfer process |
|
|
Term
| electrochemical proton gradient |
|
Definition
| crucial link between electron transport and ATP production is ____ that is established by the directional pumping of the protons across the membrane in which electron transport is occuring |
|
|
Term
| coupled to electron transport |
|
Definition
| under normal cellular conditions, ATP synthesis is ____, meaning not only that ATP synthesis depends on electron flow but also that electron flow is possible only when ATP can be synthesized |
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|
Term
|
Definition
| allow continued electron transport and oxygen consumption even in the absence of ATP synthesis. therefore, ATP is strictly dependent only electron transport, but electron transport is not necessarily dependent on ATP synthesis |
|
|
Term
|
Definition
| because electron transport is couple to ATP synthesis, the availability of ADP regulates the rate of oxidative phosphorylation and therefore of electron transport |
|
|
Term
|
Definition
electron transport and ATP generation will be ___ when the ADP concentration is high and ATP concentrantion is low
it will be ____ when ADP concentration is low and ATP concentration is high |
|
|
Term
| chemiosmotic coupling model |
|
Definition
| the exergonic transfer of electgrons through the respiratory complexes is accompanied by the unidirectional pumping of protons across the membrane in which the transport system is localized. the electrochemical proton gradient that is generated in this way represents potential energy that then provides teh dirving force for ATP synthesis |
|
|
Term
| electrochemical prton gradient |
|
Definition
| missing link between electron transport and ATP synthesis was not a high-energy chemical intermediate but an |
|
|
Term
| unidirectional pumping of protons |
|
Definition
| electron stransfer within the mitochondrial inner membrane is accompanied by ___ from the mitochondrial matrix into the external medium |
|
|
Term
|
Definition
| causes protons to be pumped out of the mitochondrial matrix |
|
|
Term
|
Definition
| components of the electron transport system are ____ oriented within the inner mitochondrial membrane. if not, protons would be pumped randomly in both directions. |
|
|
Term
|
Definition
| membrane vesicles containing complexes I, III, or IV establish |
|
|
Term
| membrane-enclosed compartment |
|
Definition
| oxidative phosphorylation requires a |
|
|
Term
|
Definition
| abolish both the proton gradient and ATP synthesis |
|
|
Term
|
Definition
| the proton gradient has enough energy to drive __ synthesis. |
|
|
Term
|
Definition
| tends to drive protons back down their concentration gradient--back into the matrix of the mitochondrion |
|
|
Term
| artificial proton gradients |
|
Definition
| are able to drive ATP synthesis in the absence of electron transport |
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|
