Biochemistry Exam part 7

ATP synthesis and mitochondrial electron transport are coupled by A) Protonmotive force B) High energy intermediates C) Proton gradient D) Both A and C are correct E) All of the above are correct

D

According to the solid state model of electron transport electron transfer is efficient because A)Electron transfer is the result of random collisions B)There are short diffusion distances between components for mobile electron carriers C)UQ is abundant D)Cytochrome c diffuses rapidly E)Electron carriers are mobile

B

During the oxidation of NADH there are several steps in which ΔEo' is sufficient for ATP synthesis. These occur within A) Complexes I, II and III B) Complexes I, III and IV C) Complexes II, III, and IV D) Complexes III, IV and V E) Complexes I, II and IV

B

The cytochromes contain which type of prosthetic group? A) FADH B) Heme C) TPP D) Zinc++ E) NAD +

B

The statement aerobic organisms use oxygen to generate energy required to maintain metabolic processes yet they risk damage caused by highly reactive oxygen molecules can be referred to as: A)Oxidation Reactive oxygen species B)Oxygen paradox C)Metabolic damage D)Thermodynamic inconsistency

B

Which of the following molecules inhibits Complex I of the electron transport chain? A) Azide B) Amytal C) Cyanide D) Arsenic E) Carbon monoxide

B

_____________ are hydrophobic molecules that dissipate ionic gradients. A) Uncouplers B) Ionophores C) Xenobiotics D) Radicals E) None of the above are correct

B

Which of the following is the best reducing agent? A) H2O B) O2 C) FADH2 D) FMNH2 E) NADH

E

The return of ______ into the mitochondrion is coupled to the formation of ______. A) Ca+2/cAMP B) Fe+2/CoQ C) ADP/NADH D) ADP/ CoASH E) H+/ATP

E

A respiratory burst is initiated when NADPH reacts with oxygen to produce which of the following? A)Superoxide anion B)Water Hydrogen peroxide C)Hydroxyl radical D)Peroxide radical

A

Antimycin A inhibits cyt b in complex III. If this inhibitor is added to a suspension of mitochondria which of the following will increase in concentration? A)NADH B)Reduced cytochrome c1 C)Reduced cytochrome c D)NAD+ E)A and D

A

Nonshivering thermogenesis is regulated by which of the following? A) Norepinephrine B) Thermogenin C) UCP2 D) ATP E) GTP

A

The NADPH required for the generation of GSH from GSSG in synthesized by the reactions of A) The pentose phosphate pathway B) Glycolysis C) The citric acid cycle D) Both A and B are correct E) Both A and C are correct

A

The function of complex III is the transfer of electrons from A) Coenzyme Q to Cyt c B) NADH to CoQ C) Succinate to UQ D) CoQ to NADH E) UQ to succinate

A

The maximum P/O ration of FADH2 is A) 1.5 B) 1.75 C) 2.0 D) 2.5 E) 3.0

A

___________ is a metal cofactor of the cytochromes. A) Fe B) S C) Co D) Zn E) Ca

A

All of the following are components of the electron transport chain except ______. A) Coenzyme Q B) Succinate dehydrogenase C) Coenzyme A D) Cytochrome c E) NADH dehydrogenase

C

Carbon monoxide inhibits which of the following? A) NADH dehydrogenase B) Ubiquinone C) Cytochrome oxidase D) Succinate dehydrogenase E) None of above are correct

C

How many ATP are generated during the oxidation of one NADH? A) 1 B) 2 C) 2.5 D) 3 E) 3.5

C

How many protons are required to drive the phosphorylation of ADP by the mitochondrial ATP synthase? A)One B)Two C)Three D)Four E)Five

C

In Complex III, electrons are tranferred from UQH2 to A) O2 B) Coenzyme Q C) Cytochrome c D) FAD E) NADH

C

Molecules involved in the conversion of oxidized proteins to their functional reduced suylfhydryl form include all of the following except A)Thioredoxin B) NADPH C) Catalase D) Thioredoxin reductase E) None of the above are correct

C

The primary function of catalase is to A) Detoxify peroxides B) Reduce the disulfide group C) Convert hydrogen peroxide to water D) Generate ROS E) Oxidize heme

C

The ultimate electron acceptor of the mitochondrial electron transport system is A) Coenzyme Q B) NADPH C) O2 D) H2O E) Both C and D are correct

C

The ultimate waste products of aerobic cellular metabolism of oxygen include A)Pyruvate B)Ethyl alcohol C)Carbon dioxide D)Carbon monoxide E)A or B

C

Evidence supporting the chemiosmotic theory inculdes all of the following except A) Inhibitors of ATP synthesis have been shown to dissipate the proton gradient B) Mitochondria with disrupted membranes cannot synthesize ATP C) ATP synthesis is depressed when mitochondrial swelling occurs as a result of osmotic changes D) The pH of a weakly buffered suspension of mitochondria rises when O2 added. E) Actively respiring mitrochondria expel protons

D

Glutathione peroxidase requires _____ for full activity A) Sulfur B) Copper C) Iron D) Selenium E) Magnesium

D

Reducing power generated in the cytoplasm can be transferred into the mitochondrion by which of the following processes? A) Glycerol phosphate shuttle B) Malate-aspartate shuttle C) The phosphate shuttle D) A and B are correct E) All of the above are correct

D

The ETC component that transfers electrons directly to oxygen is __________. A) Cyt c B) UQ C) Cyt bc1 D) Cytochrome oxidase E) Succinate dehydrogenase

D

The energy that is captured by the electron transport system is in the form of A) NADH B) FADH2 C) ATP D) Both A and B are correct E) All of the above are correct

D

The final product of oxidative phosphorylation is ________. A) Water B) ADP C) NADPH D) ATP E) FMNH2

D

The first ROS formed during the reduction of oxygen is ________. A) Hydrogen peroxide B) Hydroxyl radical C) Singlet oxygen D) Superoxide radical E) None of the above are correct

D

The reaction of Fe+2 with H2O2 results in the production of A) Hydroxyl radical B) Hydroxide ion C) Superoxide radical D) Both A and B are correct E) Both A and C are correct

D

Which of the following acts as an allosteric inhibitor of complex IV? A) FMN B) NADH C) FADH2 D) ATP E) ADP

D

Which of the following complexes contain copper? A) Complex I B) Complex II C) Complex III D) Complex IV E) Complex V

D

Which of the following is not a step in the ATP synthesizing process? A) ADP + Pi bind to the L site B) ATP is synthesized as the L conformation converts to the T conformation C) ATP is released as the T conformation converts to the O confirmation D) The O conformation binds ADP and Pi E) All of the above are correct

D

Which of the following would not be classified as a ROS? A) Oxygen B) CH3O. C) H-O-O. D) Hydroxide ion E) All of the above are ROS

D

Examples of antioxidants include all of the following except _________ A) Ascorbic acid B) β−Carotene C) α-Tocopherol D) Hydroquinone E) Gramicidin

E

Examples of uncouplers include ________. A) DNP B) Antimycin C) Gramicidin D) Both A and B are correct E) Both A and C are correct

E

Glutathione peroxidase A) Converts organic peroxides into alcohols B) Generates GSH from GSSG C) Reduces H2O2 into H2O D) Both A and B are correct E) Both A and C are correct

E

In the ATP Synthase the Fo factor A) Has three types of subunits B) Possesses ATPase activity C) In a transmembrane proton channel D) Both A and B are correct E) Both A and C are correct

E

One of the mechanisms by which vitamin C protects membrane is by A) Regenerating reduced α-tocopherol B) Reacting with proline C) Reacting with peroxyl radicals D) Both A and B are correct E) Both A and C are correct

E

ROS are generated during A) Xenobiotic metabolism B) Respiratory burst C) Ionizing radiation D) Both A and B are correct E) All of the above are correct

E

The control of aerobic respiration by _________ is referred to as respiratory control. A) HPO4-2 B) NADH C) FADH2 D) Citrate E) ADP

E

The major sources of NADH that reduce Complex I of the ETC include A) Fatty acid oxidation B) CoQ C) Pentose phosphate pathway D) The citric acid cycle E) Both A and D are correct

E

The principal sources of electrons for the electron transport system is (are) which of the following A) Glycolysis B) Citric acid cycle C) Fatty acid oxidation D) Both A and B are correct E) All of the above are correct

E