Question 1

Which of the following is NOT involved in the enzymatic inactivation of reactive oxygen species?

Accepted Answer

Vitamin C is not directly involved in the enzymatic inactivation of reactive oxygen species. Instead, it acts as an antioxidant by scavenging free radicals and protecting other molecules from oxidative damage. The other options, including superoxide dismutase, catalase, peroxiredoxin, and peroxidase, are all enzymes that directly catalyze the conversion of reactive oxygen species into less harmful compounds.

Question 2

________, which are potentially damaging, are generated because the interactions between one electron and two electron carriers are not 100% efficient.

Accepted Answer

Reactive oxygen species

Question 3

Which of the following is NOT true of respiratory control?

Accepted Answer

Oxidative phosphorylation is primarily regulated by the availability of substrates (ADP, Pi, NADH, FADH2, O2) and the electrochemical proton gradient across the mitochondrial inner membrane, rather than by classical allosteric mechanisms.

Question 4

Electron transport through NADH-Coenzyme Q reductase (Complex I) is accompanied by transfer of ________ protons from the matrix to the intermembrane space.

Accepted Answer

The answer of Electron transport through NADH-Coenzyme Q reductase (Complex...

Question 5

Which of the following is NOT an electron acceptor in the mitochondrial respiratory chain?

Accepted Answer

CoQH2, also known as ubiquinol, is a reduced form of Coenzyme Q10 (CoQ) and acts as an electron donor in the mitochondrial respiratory chain, not an electron acceptor.

Question 6

CoQ carries electrons from NADH-Coenzyme Q reductase and succinate dehydrogenase as well as other flavoproteins to CoQ:Cytochrome c oxidoreductase.

Accepted Answer

CoQ (ubiquinone) is a mobile electron carrier that shuttles electrons from NADH-Coenzyme Q reductase and succinate dehydrogenase to CoQ:Cytochrome c oxidoreductase, as well as other flavoproteins.

Question 7

All of the cytochromes in the mitochondrial respiratory chain contain the same heme moiety as found in hemoglobin.

Accepted Answer

Cytochromes in the mitochondrial respiratory chain contain different types of heme moieties, not all of which are the same as the heme found in hemoglobin.

Question 8

In animal cells the mitochondrial electron transport chain is responsible for reoxidizing most of the NADH produced by oxidative pathways regardless of the cellular compartment in which it was produced.

Accepted Answer

The mitochondrial electron transport chain is responsible for reoxidizing most of the NADH produced by oxidative pathways regardless of the cellular compartment in which it was produced in animal cells.

Question 9

Electrons are transferred through the respiratory chain from reduced NADH or FADH2 to oxygen in small steps with each step in the pathway associated with a slightly more ________ reduction potential.

Accepted Answer

The answer of Electrons are transferred through the respiratory chain...

Question 10

Calculate the free energy change associated with transporting one proton from the matrix to the intermembrane space at 37∘C where the electrical potential across the membrane is ~ = 170 mV and the △pH is +0.75.

Accepted Answer

The answer of Calculate the free energy change associated with...

Question 11

Which of the following statements about oxidative phosphorylation by ATP synthase is FALSE?

Accepted Answer

A proton gradient alone without a corresponding energy input is not sufficient to drive the synthesis of ATP is false. In fact, a proton gradient across the inner mitochondrial membrane is what drives the synthesis of ATP by ATP synthase during oxidative phosphorylation. The other statements are true.

Question 12

The ATP yield from NADH transported across the mitochondrial inner membrane by the glycerol phosphate shuttle is the same as if the malate/aspartate shuttle were used.

Accepted Answer

The ATP yield from NADH transported across the mitochondrial inner membrane by the glycerol phosphate shuttle is lower than if the malate/aspartate shuttle were used. This is because the glycerol phosphate shuttle only produces 1.5 ATP per NADH, while the malate/aspartate shuttle produces 2.5 ATP per NADH.

Question 13

Calculate the standard free energy change for the reactionFADH2 + 1/2O2 → FAD + H2O given that the standard reduction potential for the reduction of oxygen to water is +0.82 V and for the reduction of FAD to FADH2 is +0.03 V.

Accepted Answer

The answer of Calculate the standard free energy change for...

Question 14

The Q cycle is responsible for transferring electrons from a two-electron donor ________ to a one-electron acceptor ________ at the point of complex III of the mitochondrial respiratory chain.

Accepted Answer

The answer of The Q cycle is responsible for transferring...

Question 15

Energy derived from oxidation of acetyl-CoA in the citric acid cycle is used for the production of ________ in brown adipose tissue because the mitochondria are rich in UCP1.

Accepted Answer

The answer of Energy derived from oxidation of acetyl-CoA in...

Question 16

Proton-driven rotation of the c-ring of the F0 unit of the F1F0 ATP synthase is required for complete passage of protons from the intermembrane space to the matrix.

Accepted Answer

Proton-driven rotation of the c-ring of the F0 unit of the F1F0 ATP synthase is required for complete passage of protons from the intermembrane space to the matrix.

Question 17

Calculate the efficiency of energy conversion from glucose under aerobic conditions assuming that 32 moles of ATP are produced for each mole of glucose and given that △G0' for glucose oxidation is -2870kJ/mol and the △G0' for ATP hydrolysis is -32.2 kJ/mol.

Accepted Answer

The answer of Calculate the efficiency of energy conversion from...

Question 18

Which of the following statements is FALSE?

Accepted Answer

Cytochrome c is indeed a soluble electron carrier, but it is not loosely attached to the outside of the inner mitochondrial membrane; it is actually located in the intermembrane space of mitochondria. Coenzyme Q is a lipid-soluble molecule that moves within the inner mitochondrial membrane, not on its outside.

Question 19

Oligomycin is an inhibitor of ADP phosphorylation because it blocks the flow of protons through the ________.

Accepted Answer

The answer of Oligomycin is an inhibitor of ADP phosphorylation...

Quiz 14: Electron Transport, Oxidative Phosphorylation, and Oxygen Metabolism

Which of the following is NOT involved in the enzymatic inactivation of reactive oxygen species?

________, which are potentially damaging, are generated because the interactions between one electron and two electron carriers are not 100% efficient.

Which of the following is NOT true of respiratory control?

Electron transport through NADH-Coenzyme Q reductase (Complex I) is accompanied by transfer of ________ protons from the matrix to the intermembrane space.

Which of the following is NOT an electron acceptor in the mitochondrial respiratory chain?

CoQ carries electrons from NADH-Coenzyme Q reductase and succinate dehydrogenase as well as other flavoproteins to CoQ:Cytochrome c oxidoreductase.

All of the cytochromes in the mitochondrial respiratory chain contain the same heme moiety as found in hemoglobin.

In animal cells the mitochondrial electron transport chain is responsible for reoxidizing most of the NADH produced by oxidative pathways regardless of the cellular compartment in which it was produced.

Electrons are transferred through the respiratory chain from reduced NADH or FADH2 to oxygen in small steps with each step in the pathway associated with a slightly more ________ reduction potential.

Calculate the free energy change associated with transporting one proton from the matrix to the intermembrane space at 37∘C where the electrical potential across the membrane is ~ = 170 mV and the △pH is +0.75.

Which of the following statements about oxidative phosphorylation by ATP synthase is FALSE?

The ATP yield from NADH transported across the mitochondrial inner membrane by the glycerol phosphate shuttle is the same as if the malate/aspartate shuttle were used.

Calculate the standard free energy change for the reactionFADH2 + 1/2O2 → FAD + H2O given that the standard reduction potential for the reduction of oxygen to water is +0.82 V and for the reduction of FAD to FADH2 is +0.03 V.

The Q cycle is responsible for transferring electrons from a two-electron donor to a one-electron acceptor at the point of complex III of the mitochondrial respiratory chain.

Energy derived from oxidation of acetyl-CoA in the citric acid cycle is used for the production of ________ in brown adipose tissue because the mitochondria are rich in UCP1.

Proton-driven rotation of the c-ring of the F0 unit of the F1F0 ATP synthase is required for complete passage of protons from the intermembrane space to the matrix.

Calculate the efficiency of energy conversion from glucose under aerobic conditions assuming that 32 moles of ATP are produced for each mole of glucose and given that △G0' for glucose oxidation is -2870kJ/mol and the △G0' for ATP hydrolysis is -32.2 kJ/mol.

Which of the following statements is FALSE?

Oligomycin is an inhibitor of ADP phosphorylation because it blocks the flow of protons through the ________.