front 1 For mitochondria where an uncoupler for oxidative phosphorylation is
present, which statement is TRUE? | back 1 D) The amount of ATP generated from FADH2 will be less than the amount of ATP generated from NADH. |
front 2 Which statement regarding oxidative phosphorylation is TRUE? | back 2 C) Proton transfer through the Fo subunit of ATP synthase is required in order for ATP synthesis to occur. |
front 3 The consumption of acetyl-CoA by the citric acid cycle is DECREASED
under which condition? | back 3 D) the mitochondrial ATP synthase being inactive |
front 4 Which molecule can reduce the proton gradient in
mitochondria? | back 4 D) All of the answers are correct. |
front 5 How many molecules of water are produced by the electron-transport
chain during the complete aerobic oxidation of one | back 5 C) 5 H2O |
front 6 The electron-transport chain and ATP synthase are effectively
coupled. Which statement BEST describes how this occurs? | back 6 B) The electron-transport chain generates an electrochemical gradient that provides energy for the production of ATP. |
front 7 Which statement is NOT true of electron transport? | back 7 A) The mobile electron carrier coenzyme A is located in the inner mitochondrial membrane. |
front 8 During oxidative phosphorylation, the proton motive force
(electrochemical gradient) that is generated by electron
transport | back 8 C) drive transport processes essential to oxidative phosphorylation. |
front 9 Coenzyme Q is a prosthetic group for which of the following complexes
in the electron transport chain? | back 9 E) None of the answers is correct. |
front 10 Which statement does NOT describe a difference between the inner and
outer mitochondrial membranes? | back 10 B) The outer mitochondrial membrane is permeable to large proteins
(Mr > 10,000), whereas the inner mitochondrial |
front 11 What factor makes the outer mitochondrial membrane permeable to
protons? | back 11 C) porins |
front 12 Which cofactor is MOST commonly involved as a cosubstrate in
catabolic reactions where a metabolite is oxidized? | back 12 A) NAD+ |
front 13 Which statement is FALSE regarding flavoproteins? | back 13 D) They are always integral membrane proteins. |
front 14 Complex III contains which cofactor as a prosthetic group? | back 14 A) iron-sulfur clusters |
front 15 Which characteristic describes heme a but not heme c? | back 15 D) contains two propionate substituents on the porphyrin ring |
front 16 Which component of the electron-transport chain is NOT an integral
membrane protein? | back 16 B) cytochrome c |
front 17 Which protein associated with electron transport below is NOT a
flavoprotein? | back 17 C) cytochrome oxidase |
front 18 If a drug that specifically prevented the interaction of cytochrome c
with other proteins was added to respiring mitochondria | back 18 C) Reduced cofactors (NADH/FADH2) would accumulate. |
front 19 Which statement is FALSE concerning Complex III and the Q
cycle? | back 19 E) Overall, in each cycle one cytochrome c is reduced for every QH2 oxidized (net). |
front 20 How many of cytochrome c need to be reoxidized for every oxygen
molecule (O2) converted to water? | back 20 D) four |
front 21 Which list shows the proteins in the CORRECT order from highest to
lowest reduction potential? | back 21 D) ETF:Q oxidoreductase → ETF → acyl-CoA dehydrogenase |
front 22 What is the P:O ratio for electrons entering the electron-transport
chain that originate from reoxidation of
acyl-CoA | back 22 D) approximately the same as the P:O ratio for Complex II reoxidation |
front 23 Which complex in the electron-transport chain contains copper
ions? | back 23 D) Complex IV |
front 24 Cytochrome c can be reduced directly by small molecules such as
ascorbate (vitamin C). If ascorbate is added to an | back 24 C) Oxygen would be reduced to water. |
front 25 What compound is a product of the reaction involving the superoxide
free radical catalyzed by superoxide dismutase? | back 25 B) hydrogen peroxide |
front 26 In some organisms, an alternative oxidase will accept electrons from
ubiquinol and reduce oxygen to water with no | back 26 B) decreased P:O ratio |
front 27 During the operation of the malate-aspartate shuttle, what process
does NOT occur? | back 27 B) transfer of amino groups from glutamate to oxaloacetate in the cytosol |
front 28 Which statement is TRUE regarding the reduction potential of
mitochondrial glycerol 3 phosphate dehydrogenase? | back 28 C) It will be higher than that of NADH but lower than that of Complex III. |
front 29 Which statement is FALSE regarding 2,4-dinitrophenol? | back 29 D) It requires a specific transporter to enter mitochondria. |
front 30 What effect will increasing the number of c subunits in ATP synthase
have on the P:O ratio? | back 30 D) It will decrease for both NADH and FADH2. |
front 31 Which statement is FALSE regarding ATP synthase? | back 31 E) ADP binds more tightly to the active site than ATP. |
front 32 Which statement is TRUE regarding the gamma (γ) subunit of ATP
synthase? | back 32 A) It contains mostly α-helical regular secondary structure. |
front 33 Which step is NOT part of the proton-translocation process in ATP
synthase? | back 33 D) An arginine in the a subunit is reversibly protonated and deprotonated in each proton binding event. |
front 34 In which pairing are both transporters symports? | back 34 B) phosphate translocase and pyruvate translocase |
front 35 Which statement explains why the [ATP]/[ADP][Pi] ratio is relatively
stable in a cell? | back 35 B) ATP consumption is balanced by ATP synthase activity. |
front 36 Which statement does NOT describe characteristics of the protein
inhibitor IF1? | back 36 C) This protein will bind to the FO portion of ATP synthase. |
front 37 What will NOT occur when 2,4-dinitrophenol (an uncoupler of oxidative
phosphorylation) is added to actively
respiring | back 37 A) The P:O ratio will increase. |
front 38 Cytochrome P-450 gets its name from what characteristic? | back 38 C) It absorbs light at 450 nm. |
front 39 What is the role of cytochrome c in apoptosis? | back 39 D) It forms a complex with other proteins to generate an apoptosome. |
front 40 Which protein is NOT portion encoded in human mitochondrial
DNA? | back 40 D) cytochrome c |
front 41 What mechanism accounts for mitochondrial inheritance in sexual
reproduction in animals? | back 41 D) Male mitochondria are degraded after fertilization. |
front 42 Almost all of the oxygen (O2) one consumes in breathing is converted
to: | back 42 D) water. |
front 43 Which of the following electron carriers is NOT able to transfer one
electron at a time? | back 43 A) NADH |
front 44 A new compound isolated from mitochondria is claimed to represent a
previously unrecognized carrier in the electron | back 44 E) When added to a mitochondrial suspension, coenzyme Z is taken up very rapidly and specifically by the mitochondria. |
front 45 Antimycin A blocks electron transfer between cytochromes b and c1. If
intact mitochondria were incubated with antimycin | back 45 B) cytochrome a3 |
front 46 Reduced QH2 is NOT formed by which of the following? | back 46 C) Complex III and cytochrome c |
front 47 In the reoxidation of QH2 by purified ubiquinone-cytochrome c
reductase (Complex III) from heart muscle, the
overall | back 47 A) cytochrome c is a one-electron acceptor, whereas QH2 is a two-electron donor. |
front 48 Which statement is NOT a feature of Complex IV? | back 48 E) In order to generate two water molecules, Complex IV must go through the catalytic cycle two times. |
front 49 Which statement is NOT true of the proton motive force (pmf)? | back 49 C) Generation of the pmf in mitochondria requires succinate. |
front 50 Cyanide, oligomycin, and 2,4-dinitrophenol (DNP) are inhibitors of
mitochondrial aerobic phosphorylation. Which statement | back 50 B) Cyanide inhibits the respiratory chain, whereas oligomycin and 2,4-dinitrophenol inhibit the synthesis of ATP. |
front 51 If electron transfer in tightly coupled mitochondria is blocked (with
antimycin A) between cytochrome b and cytochrome
c1, | back 51 A) all ATP synthesis will stop. |
front 52 In normal mitochondria, the rate of NADH consumption (oxidation)
will: | back 52 E) All of the answers are correct. |
front 53 Which statement about the chemiosmotic theory is CORRECT? | back 53 A) Electron transfer in mitochondria is accompanied by an asymmetric
release of protons on one side of the inner |
front 54 Which statement about the chemiosmotic theory is FALSE? | back 54 E) The membrane ATPase, which plays an important role in other
hypotheses for energy coupling, has no significant role in |
front 55 Upon the addition of 2,4-dinitrophenol (DNP) to a suspension of
mitochondria carrying out oxidative phosphorylation linked | back 55 A) Oxygen consumption decreases. |
front 56 Uncoupling of mitochondrial oxidative phosphorylation: | back 56 C) halts mitochondrial ATP formation but allows continued O2 consumption. |
front 57 2,4-Dinitrophenol and oligomycin inhibit mitochondrial oxidative
phosphorylation. 2,4-Dinitrophenol is an uncoupling | back 57 A) allow electron transfer in the presence of oligomycin. |
front 58 Which statement about energy conservation in the mitochondrion is
FALSE? | back 58 D) Uncouplers (such as dinitrophenol) have exactly the same effect on
electron transfer as inhibitors such as cyanide; both |
front 59 Which statement is CORRECT concerning the mitochondrial ATP
synthase? | back 59 E) When it catalyzes the ATP synthesis reaction, the ΔG'° is actually close to zero. |
front 60 When the ΔG'° of the ATP synthesis reaction is measured on the
surface of the ATP synthase enzyme, it is found to be close | back 60 D) stabilization of ATP relative to ADP by enzyme binding. |
front 61 During oxidative phosphorylation, the proton motive force that is
generated by electron transport is used to: | back 61 C) induce a conformational change in the ATP synthase. |
front 62 The oxidation of a particular hydroxy substrate to a keto product by
mitochondria has a P/O ratio of less than 2. The
initial | back 62 C) reduction of a flavoprotein. |
front 63 The relative concentrations of ATP and ADP control the cellular rates
of: | back 63 E) All of the answers are correct. |
front 64 The rate of oxidative phosphorylation in mitochondria is controlled
primarily by: | back 64 D) the mass-action ratio of the ATD-ADP system. |
front 65 Which factor is NOT controlled by hypoxia-inducible factor
(HIF-1)? | back 65 D) Compex I of the respiratory chain |
front 66 Mammals produce heat by using which endogenous uncoupling
agent? | back 66 B) the protein thermogenin |
front 67 Which phrase BEST describes the role of mitochondria in
apoptosis? | back 67 E) both escape of cytochrome c into the cytoplasm and an increase in permeability of outer membrane |
front 68 Mutations in mitochondrial genes do NOT play a role in: | back 68 B) cystic fibrosis. |
front 69 Which statement about human mitochondria is TRUE? | back 69 A) About 900 mitochondrial proteins are encoded by nuclear genes. |