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Example Questions
Example Question #101 : Carbohydrate Metabolism
Suppose that a scientist is simultaneously measuring both the amount of oxygen and the amount of glucose that is being used by cells. If a chemical were added that inhibited the electron transport chain, what would be expected to happen to the consumption of oxygen and glucose?
Both oxygen and glucose consumption decrease
Both oxygen and consumption will remain unchanged
Oxygen consumption increases while glucose consumption decreases
Both oxygen and glucose consumption increase
Oxygen consumption decreases while glucose consumption increases
Oxygen consumption decreases while glucose consumption increases
Aerobic respiration is a process that utilizes the electron transport chain in order to oxidize glucose into energy. If a chemical were added that inhibited the electron transport chain, the cell would no longer be able to fully oxidize glucose. Therefore, oxygen consumption will decrease. Furthermore, since the cell is now in a situation in which it is not able to make as much energy per glucose molecule as before, it will need to increase its consumption of glucose in order to generate enough energy through anaerobic respiration alone.
Example Question #1 : Other Electron Transport Chain Concepts
ATP synthase can be inhibited exclusively by __________.
Rotenone
Cyanide
Oligomycin
Antimycin
Oligomycin
Oligomycin is an antibiotic that inhibits ATP synthase. It works by binding to the stalk of ATP synthase. This prevents proton re-entry into the mitochondrial matrix. This results in a halt of the proton motive force that ATP synthase uses to created ATP from one unit of ADP and one unit of inorganic phosphate. Rotenone is a pesticide and fish poison that inhibits NADH dehydrogenase in complex I causing the levels of NADH to increase. This results in a halt of the electron transport chain. Antimycin is a fungal antibiotic that inhibits complex III of the electron transport chain. Antimycin prevents the transfer of electrons through the cytochrome b-c complex. Cyanide is a gas that inhibits complex IV of the electron transport chain. Cyanide combines with cytochrome oxidase and prevents the transfer of electrons to oxygen.
Example Question #1 : Other Electron Transport Chain Concepts
Complex III can be inhibited exclusively by __________.
Oligomycin
Rotenone
Cyanide
Antimycin
Antimycin
Antimycin is a fungal antibiotic that inhibits complex III of the electron transport chain. Antimycin prevents the transfer of electrons through the cytochrome b-c complex. Oligomycin is an antibiotic that inhibits ATP synthase. It works by binding to the stalk of ATP synthase. This prevents proton re-entry into the inner mitochondrial matrix. This results in a halt of the proton motive force that ATP synthase uses to created ATP from one unit of ADP and one unit of inorganic phosphate. Rotenone is a pesticide and fish poison that inhibits NADH dehydrogenase in complex I causing the levels of NADH to increase. This results in a halt of the electron transport chain. Cyanide is a gas that inhibits complex IV of the electron transport chain. Cyanide combines with cytochrome oxidase and prevents the transfer of electrons to oxygen.
Example Question #1 : Other Electron Transport Chain Concepts
Complex I can be inhibited exclusively by __________.
Cyanide
Antimycin
Oligomycin
Rotenone
Rotenone
Rotenone is a pesticide and fish poison that inhibits NADH dehydrogenase in complex I causing the levels of NADH to increase. This results in a halt of the electron transport chain. Oligomycin is an antibiotic that inhibits ATP synthase. It works by binding to the stalk of ATP synthase. This prevents proton re-entry into the mitochondrial matrix. This results in a halt of the proton motive force that ATP synthase uses to created ATP from one unit of ADP and one unit of inorganic phosphate. Antimycin is a fungal antibiotic that inhibits complex III of the electron transport chain. Antimycin prevents the transfer of electrons through the cytochrome b-c complex. Cyanide is a gas that inhibits complex IV of the electron transport chain. Cyanide combines with cytochrome oxidase and prevents the transfer of electrons to oxygen.
Example Question #3 : Other Electron Transport Chain Concepts
Complex IV can be inhibited exclusively by __________.
Rotenone
Cyanide
Oligomycin
Antimycin
Cyanide
Cyanide is a gas that inhibits complex IV of the electron transport chain. Cyanide combines with cytochrome oxidase and prevents the transfer of electrons to oxygen. Antimycin is a fungal antibiotic that inhibits complex III of the electron transport chain. Antimycin prevents the transfer of electrons through the cytochrome b-c complex. Oligomycin is an antibiotic that inhibits ATP synthase. It works by binding to the stalk of ATP synthase. This prevents proton re-entry into the mitochondrial matrix. This results in a halt of the proton motive force that ATP synthase uses to created ATP from one unit of ADP and one unit of inorganic phosphate. Rotenone is a pesticide and fish poison that inhibits NADH dehydrogenase in complex I causing the levels of NADH to increase. This results in a halt of the electron transport chain.
Example Question #1 : Other Electron Transport Chain Concepts
Which of the following is a function of coenzyme Q10 (CoQ10) during the electron transport chain (ETC)?
Donates electrons to FADH
Oxidizes enzyme complex III
Oxidizes enzyme complex II
The ultimate acceptor of electrons
Reduces enzyme complex I
Oxidizes enzyme complex II
CoQ10 is produced in the liver and oxidizes enzyme complex II. It is subsequently oxidized by enzyme complex III in the ETC. Oxygen is the final acceptor of electrons in the ETC.
Example Question #3 : Other Electron Transport Chain Concepts
Oxygen is known as the "terminal electron receptor" in the electron transport chain. Suppose an organism lacks the ability to breathe in oxygen.
What is the most likely effect an oxygen deficit would have on the electron transport chain in mitochondria?
The oxygen would not be able to interact with ATP synthase and thus ATP production would halt, however, the electron transport chain would continue to function normally otherwise.
Without a terminal electron acceptor, the electrons of and would have nowhere to be released, and all of the enzyme complexes involved with the electron transport chain would be "saturated" with electrons and the entire electron transport chain would cease to function, halting production of ATP.
The mitochondria would synthesize new complexes for the electron transport chain and ATP production would continue.
A mitochondria would use an alternative terminal electron receptor such as nitrogen or carbon dioxide, the electron transport chain would continue to function.
Nothing would happen, the electron transport chain would function normally.
Without a terminal electron acceptor, the electrons of and would have nowhere to be released, and all of the enzyme complexes involved with the electron transport chain would be "saturated" with electrons and the entire electron transport chain would cease to function, halting production of ATP.
Without a terminal electron acceptor, the electrons of and would have nowhere to be released, all of the complexes would be "backed up" as each complex would not be able to pass off its electrons to the next complex. ATP production would come to a standstill.
Without oxygen to receive the electrons, the entire flow of the electron transportation chain halts, as well as ATP production. It is the continuous flow of electrons through the ETC complexes that allows a mitochondria to harness the energy of the electrons that and donate. This energy is used to pump protons across the intermembrane space of a mitochondria. The re-entry of these protons through ATP synthase is what drives the production of ATP.
In short, no electron flow means no proton pumps and no re-entry of those protons through ATP synthase. A cell could potentially resort to glycolysis to produce ATP, and can regenerate or using anaerobic fermentation such as alcohol fermentation of lactic acid fermentation.
Example Question #1 : Other Electron Transport Chain Concepts
To which component of the electron transport chain does cyanide bind?
Cyanide binds the electron transport chain at the level of coenzyme Q
Cyanide binds the electron transport chain at the level of complex IV
Cyanide binds ATP synthase
Cyanide binds the electron transport chain at the level of complex I
Cyanide binds the electron transport chain at the level of complex III
Cyanide binds the electron transport chain at the level of complex IV
The electron transport chain passes electrons thru its main components: complex I (NADH dehydrogenase), coenzyme Q, complex III, cytochrome C, and complex IV. Complex IV is the cytochrome oxidase complex and it is inhibited by cyanide, carbon monoxide and azide. Cyanide binds irreversibly to complex IV preventing electron transfer.
Example Question #41 : Electron Transport And Oxidative Phosphorylation
Reactive oxygen species are by-products of the electron transport chain. Which of the following are considered reactive oxygen species?
All of these
None of these
Hydroxyl radical
Hydrogen peroxide
Superoxide
All of these
Reactive oxygen species are superoxide, hydrogen peroxide, and hydrogen radicals. They are degraded by catalase, superoxide dismutase, and glutathione peroxidase. Neutrophils use reactive oxygen species to kill bacteria during the phagocytic oxidative burst.
Example Question #42 : Electron Transport And Oxidative Phosphorylation
Which of the following are uncouplers of the electron transport chain?
I. Carbon monoxide
II. 2,4-Dinitrophenol
III. Nitric oxide
IV. Aspirin
I, III, and IV
I and II
I and III
I and IV
II and IV
II and IV
Uncouplers of the electron transport chain decrease the proton gradient and thus decrease ATP synthesis. Most energy from the electron transport chain is released as heat. The most common uncouplers are 2,4-dinitrophenol and aspirin, as well as thermogenin. Carbon monoxide is an inhibitor of the electron transport chain, not an uncoupler. Nitric oxide does not affect directly the electron transport chain.
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