Week 4 Assignment QUESTIONS AND ANSWERS 100 VERIFIED A GUARANTEED

Week #4 Assignment QUESTIONS AND ANSWERS 100% VERIFIED A+ GUARANTEED ____ were responsible for the accumulation of significant levels of atmospheric oxygen on Earth between 2.4 and 2.7 billion years ago. a. aerobic bacteria b. cyanobacteria c. plants d. anaerobic bacteria e. mitochondria Which of the following would NOT be found as part of the mitochondrial matrix? a. ribosomes larger than those in the cytoplasm of the cell b. circular DNA c. enzymes d. tRNAs e. ribosomes smaller than those in the cytoplasm of the cell Each pair of electrons transferred from NADH to oxygen by means of the electron transport chain releases sufficient energy to drive the formation of approximately how many molecules of ATP? a. one b. two c. three d. thirty-six e. more than thirty-six Which of the following are reduced coenzymes? a. NADH and FADH2 b. NAD+ and FAD c. ATP and GTP d. coenzyme A and TCA e. NADP and FAD In what form does a portion of the product of glycolysis enter the TCA cycle? a. acetyl CoA b. pyruvate c. NADH d. glucose e. citric acid Types of electron carriers found in the electron transport chain of the inner mitochondrial membrane do NOT include: a. flavoproteins b. cytochromes c. iron-sulfur proteins d. ubiquinone e. NAD Which of the following statements is FALSE about cytochrome oxidase? a. It is also known as complex IV in the electron transport chian b. it acts as a proton pump c. activity of the enzyme leads to production of oxygen d. for every molecule of oxygen reduced, either protons move through the complex e. translocation of protons through the complex is coupled to conformational changes generated by the release of energy that accompanies the transfer of electrons Which of the following is NOT a feature of oxidative phosphorylation? a. direct transfer of phosphate from a substrate molecule to ADP, also known as substrate-level phosphorylation b. an electrochemical gradient across the inner mitochondrial membrane c. transport of protons across the inner mitochondrial membrane d. NADH dehydrogenase e. cytochromes The Fo portion of the ATP synthase: a. contains a channel through which protons can move from the intermembrane space to the mitochondrial matrix b. is composed of different five polypeptides c. is located in the outer mitochondrial membrane d. has the same structure in a wide variety of different organisms e. all of these statements are true about the Fo of mitochondrial ATP synthase The F1 portion of mitochondrial ATP synthase: a. is composed of four polypeptides b. is coded for by mitochondrial DNA and synthesized in the matrix c. is located in the outer mitochondrial membrane d. synthesizes ATP e. is a protein that lacks quaternary structure Which one of the following statements is FALSE regarding action of the Fo portion of ATP synthase? a. the c subunits are organized into a ring-shaped complex b. subunits of the c ring move successively past a stationary a subunit c. the g subunit rotates at rates of more than 100 revolutions per second d. the movement of electrons through the membrane drives the rotations of the ring of c subunits e. rotation of the c ring of Fo leads to the synthesis and release of ATP by catalytic subunits of F1 portion of the enzyme Which of the following statements about mitochondrial disease is TRUE? a. individuals with mutations in the same mitochondrial gene will all exhibit the same disorder b. all mitochondrial diseases are mild and are easily tolerated by the patient c. oxygen radicals formed in mitochondria cause an increased mutation rate in mtDNA relative to nuclear DNA d. scientists have described a clear connection between mutations in mtDNA and aging e. mitochondrial diseases will always be inherited by offspring of the same father Observations of mitochondria within living cells have shown that: a. mitochondria cannot fuse with one another b. their shape is always cylindrical c. they can exist as a highly branched, interconnected tubular network d. they cannot split apart e. they can exist as individual conical organelles Anaerobic metabolism provides energy for muscle contraction when the supply of ___ is limited. a. oxygen b. ATP c. creatine d. glucose e. glycogen During aerobic exercise, muscle fibers first use glycogen for energy, and then they switch to use of: a. creatine phosphate b. free fatty acids c. glucose d. lactic acid e. creatine At the end of the electron transport chain, low-energy electrons are transferred to ____, which is the terminal electron acceptor, forming ____. a. molecular oxygen (O2); glucose b. water (H2O); molecular oxygen (O2) c. pyruvate; lactate d. molecular oxygen (O2); water (H2O) e. NAD+; NADH To what is the 2-carbon fragment of acetyl CoA added to make citric acid at the start of the Krebs cycle? a. oxaloacetate b. citric acid c. succinate d. ketoglutarate e. isocitric acid The composition of the inner mitochondrial membrane is MOST like that of: a. the outer mitochondrial membrane b. the plasma membrane of a eukaryotic cell c. bacterial plasma membranes d. the nuclear membrane e. the endoplasmic reticulum (ER) ATP synthesis is located: a. in the plasma membrane b. in the outer membrane of the mitochondrion c. in the matrix of the mitochondrion d. in the inner membrane of the mitochondrion e. in the intermembrane space According to the rotational catalysis model ____ energy stored in the proton gradient is transduced into ____ energy of a rotating stalk, which is transduced into ____ energy stored in ATP. a. mechanical; electrical; chemical b. chemical; electrical; mechanical c. electrical; chemical; mechanical d. electrical; mechanical; chemical e. chemical; mechanical; electrical Which of the following BEST describes the mechanism by which ATP is synthesized by ATP synthase using the energy of proton movement? a. protons move through the Fo subunit and thereby allow ADP and Pi to bind the enzyme b. protons move through the Fo subunit and rotate the Y subunit, inducing changes in the conformation of the B subunit catalytic sites and allowing formation and release of ATP c. Protons bind to the F1 subunit and electrostatically join ADP and Pi d. Protons allow substrate-level phosphorylation to occur, much like that in glycolysis e. protons are channeled through the F1 subunit into the mitochondrial matrix where they release energy that is captured by ADP The three catayltic sites of ATP synthase _____. a. have different substrate binding affinities b. have different product binding affinities c. at any one time are present in different conformations d. pass sequentially through their three different conformations e. all of these are correct On average, how many ATPs would be made if 6 MADH and 4 FADH2 molecules donated their high-energy electrons to the mitochondrial electron transport chain? a. 10 b. 24 c. 30 d. 36 Types of electron carriers for the electron-transport chain include all of the following EXCEPT ____. a. ubiquinone b. cytochromes c. molybdenum d. flavoproteins How many catalytic sites does ATP synthase possess? a. 1 b. 2 c. 3 d. 6 What are the two components of the proton-motive force? a. pH gradient and equilibrium b. pH gradient and voltage c. voltage and ATP d. voltage and lipid-soluble agents Most of the ATP made during cellular respiration is generated through _____. a. glycolysis b. the Calvin cycle c. the Krebs cycle d. oxidative phosphorylation In what molecule is most of the energy of glucose stored at the end of glycolysis? a. pyruvate b. acetyl CoA c. ethanol d. NADH What advantage do the cristae confer on the mitochondria? a. they allow the mitochondria to shrink b. they greatly increase the surface area for aerobic respiration machinery c. they allow swelling of mitochondria d. they activate the matrix How is the number of mitochondria increased? a. through binary fission of preexisting mitochondria b. by budding off the Golgi apparatus c. by budding off of the rough endoplasmic reticulum d. by spontaneous self-assembly through fusion