Chapter 14 Exam II Test Bank Part 1 (C)
Food molecules are ultimately converted into acetyl CoA,. The e- removed during production of acetyl CoA are added to NAD+ & FAD to reduce into NADH & FADH2. The 2 C atoms in acetyl group of acetyl CoA are then fed into the CTC, where they are oxidized into 2 CO2. The e- removed during oxidation are also captured by NADH & FADH2. The high-energy e- in all of these carriers, which derived from carbons of food molecules are now transferred to the protein complexes in the ETC.
Based upon what you know about metabolism, explain how electrons are stripped from food molecules and used to drive the electron-transport chain.
Battery have chemicals that generate (-) ions at one pole, and it is able to cause the continuous transfer of e- along a wire if that pole is connected to the other end of the battery. The energy released by the e- transfer process can be harnessed to do useful work. Similarly, the energy released by the e- transfers that occur between protein complexes in the ETC does useful work when it drives the pumping of H+ to one side of the membrane, since the resulting proton gradient is then used to generate chemical energy in the form of ATP.
Describe how a flashlight battery can convert energy into useful work. Explain how this is similar to the energy conversions in the mitochondria.
(b) protons, down
Fill In The Blank: Osmosis describes the movement of H2O across a membrane and down its concentration gradient. In chemiosmosis, useful energy is harnessed by the cell from the movement of ______ across the inner mitochondrial membrane into the matrix _______ a concentration gradient. (a) ATP, against (b) protons, down (c) electrons, down (d) ADP, against
Answer: oxidation-reduction
Finish The Following Statement: Electron transfer in the chain occurs in a series of ___________reactions
Answer: pyruvate and fatty acids
Finish The Following Statement: Mitochondria can use both ____ and ______ directly as fuel.
Answer: acetyl groups, CO₂
Finish The Following Statement: The citric acid cycle oxidizes ________ and produces _________ as a waste product.
Answer: ubiquinone
Finish The Following Statement: The first mobile electron carrier in the respiratory chain is ________________
Answer: oxidative phosphorylation
Finish The Following Statement: The synthesis of ATP in mitochondria is also known as ______.
Answer: Cytochrome C
Finish The Following Statement: _______ is a small protein that acts as the second mobile electron carrier in the respiratory chain.
Answer: Oxygen
Finish The Following Statement: __________ acts as the final electron acceptor in the electron-transport chain.
Answer: Cytochrome c oxidase
Finish The Following Statement: ___________ transfers electrons to oxygen in the ETC
Answer: NADH dehydrogenase
Finish The Following Statement: NADH donates electrons to _________, which is the 1st of the three respiratory enzyme complexes in the mitochondrial electron-transport chain.
Answer: NADH
Finish The Following Statement: _______ produced in the citric acid cycle donates electrons to the electron-transport chain.
About 30. Glycolysis of a single glucose molecule generates 2 ATP molecules. Oxidative phosphorylation in the mitochondria generates an additional 28
How many molecules of ATP can a single molecule of glucose generate?
(c) O2 is reduced to H2O. The final action of the ETC is the production of water
In oxidative phosphorylation, ATP production is coupled to the events in the ETC. What is accomplished in the final electron-transfer event in the electron-transport chain? (a) OH- is oxidized to O2 (b) pyruvate is oxidized to CO2 (c) O2 is reduced to H2O (d) NAD+ is reduced to NADH
A. Porin: outer membrane. B. The mitochondrial genome: the matrix. C. The citric acid cycle enzymes: the matrix.
In which of the four compartments of a mitochondrion are each of the following located? A. porin B. the mitochondrial genome C. citric acid cycle enzymes
D. proteins of the ETC: inner membrane. E. ATP synthase: inner membrane. F. membrane transport protein for pyruvate: inner membrane.
In which of the four compartments of a mitochondrion are each of the following located? D. proteins of the electron-transport chain E. ATP synthase F. membrane transport protein for pyruvate
(b) NAD+ + H-
NADH contains a high-energy bond that, when cleaved, donates a pair of electrons to the ETC. What are the immediate products of this bond cleavage? (a) NAD+ + OH- (b) NAD+ + H- (c) NAD- + H+ (d) NAD + H
(d) the proteins of the ETC in a chloroplast are found in the thylakoid membrane
Photosynthesis takes place in chloroplasts and uses light energy to generate high-energy electrons, which are passed along an ETC. Where are the proteins of the ETC located in chloroplasts? (a) thylakoid space (b) stroma (c) inner membrane (d) thylakoid membrane
In the absence of O2, the respiratory chain no longer pumps H+, and thus no H+ electrochem gradient is generated across the bacterial membrane. In these conditions, the ATP synthase uses some of the ATP generated by glycolysis in the cytosol to pump H+ out of the bacterium, thus forming the H+ gradient across the membrane that the bacterium requires for importing vital nutrients by coupled transport.
Some bacteria can live both aerobically and anaerobically. How does the ATP synthase in the plasma membrane of the bacterium help such bacteria to keep functioning in the absence of oxygen?
(c) Contrary to the name "oxidative phosphorylation", the phosphorylation does not depend on an oxidative rxn, but rather on the reduction of O2, converting it to water.
Stage 1 of oxidative phosphorylation requires the movement of electrons along the electron-transport chain coupled to the pumping of protons into the intermembrane space. What is the final result of these electron transfers? (a) OH- is oxidized to O2 (b) pyruvate is oxidized to CO2 (c) O2 is reduced to H2O (d) H- is converted to H2
B is false because the Outer membrane has porins. And the inner membrane has nothing to do with pyruvate or CTC. The matrix is involved with that
Statements B & C are FALSE. Why is B false? A) The number and location of mitochondria within a cell can change, depending on both the cell type and the amount of energy required. B) The inner mitochondrial membrane contains porins, which allow pyruvate to enter for use in the citric acid cycle. C) The inner mitochondrial membrane is actually a series of discrete, flattened, membrane-enclosed compartments called cristae, similar to what is seen in the Golgi apparatus. D) The intermembrane space of the mitochondria is chemically equivalent to the cytosol with respect to pH and the small molecules present.
C is false, pay attention to the wording. Cristae is just folding back and forth of the same membrane, not flattened
Statements B & C are FALSE. Why is C false? A) The number and location of mitochondria within a cell can change, depending on both the cell type and the amount of energy required. B) The inner mitochondrial membrane contains porins, which allow pyruvate to enter for use in the citric acid cycle. C) The inner mitochondrial membrane is actually a series of discrete, flattened, membrane-enclosed compartments called cristae, similar to what is seen in the Golgi apparatus. D) The intermembrane space of the mitochondria is chemically equivalent to the cytosol with respect to pH and the small molecules present.
The citric acid cycle stops when O2 is removed because several steps in the cycle require the oxidized forms of NAD+ & FAD. In the absence of O2, these carriers can be reduced to NADH & FADH2 by the rxns of the CTC but cannot be reoxidized by the ETC that participates in oxidative phosphorylation. So it stops
The CTC generates NADH & FADH2, which are then used in oxidative phosphorylation to make ATP. The CTC and oxidative phosphorylation are separate processes. And the CTC doesn't even use O2. So why is it that the citric acid cycle stops almost immediately when O2 is removed?
(a) chemiosmotic coupling. B C & D are the processes that are coupled together in chemiosmotic coupling
The link between bond-forming reactions and membrane transport processes in the mitochondria is called __________________. (a) chemiosmotic coupling. (b) proton pumping. (c) electron transfer. (d) ATP synthesis.
(d) cytochrome c oxidase. This is the last complex of the ETC. The reduction of O2 into H2O signals the end of the ETC
Which component of the electron-transport chain is required to combine the pair of electrons with molecular oxygen? (a) cytochrome c (b) cytochrome b-c1 complex (c) ubiquinone (d) cytochrome c oxidase
(b) cytochrome c. Cytochrome C is an electron carrier. Each complex of the ETC has a H+ pump tho.
Which of the following components of the electron-transport chain does not act as a proton pump? (a) NADH dehydrogenase (b) cytochrome c (c) cytochrome c reductase (d) cytochrome c oxidase
d) Is false, the process it is describing is substrate-level phosphorylation.
Which of the following is not part of oxidative phosphorylation? (a) Molecular oxygen serves as a final electron acceptor. (b) FADH2 and NADH become oxidized as they transfer a pair of electrons to the electron-transport chain. (c) The electron carriers in the electron-transport chain toggle between reduced and oxidized states as electrons are passed along. (d) ATP molecules are produced in the cytosol as glucose is converted into pyruvate.
(c) Mitochondrial division is mechanistically similar to prokaryotic cell division.
Which of the following statements about mitochondrial division is true? (a) Mitochondria divide in synchrony with the cell. (b) The rate of mitochondrial division is the same in all cell types. (c) Mitochondrial division is mechanistically similar to prokaryotic cell division. (d) Mitochondria cannot divide and produce energy for the cell at the same time.
(b) It contains transporters for ATP molecules
Which of the following statements describes the mitochondrial inner membrane? (a) It is permeable to molecules with molecular mass as high as 5000 daltons. (b) It contains transporters for ATP molecules. (c) It contains proteins that are released during apoptosis. (d) It contains enzymes required for the oxidation of pyruvate & fatty acids
(c) It contains proteins that are released during apoptosis.
Which of the following statements describes the mitochondrial intermembrane space? (a) It is permeable to molecules with molecular mass as high as 5000 daltons. (b) It contains transporters for ATP molecules. (c) It contains proteins that are released during apoptosis. (d) It contains enzymes required for the oxidation of pyruvate & fatty acids.
(d) It contains enzymes required for the oxidation of pyruvate & fatty acids. In addition those required for the CTC
Which of the following statements describes the mitochondrial matrix? (a) It is permeable to molecules with molecular mass as high as 5000 daltons. (b) It contains transporters for ATP molecules. (c) It contains proteins that are released during apoptosis. (d) It contains enzymes required for the oxidation of pyruvate & fatty acids
(a) It is permeable to molecules with molecular mass as high as 5000 daltons.
Which of the following statements describes the mitochondrial outer membrane? (a) It is permeable to molecules with molecular mass as high as 5000 daltons. (b) It contains transporters for ATP molecules. (c) It contains proteins that are released during apoptosis. (d) It contains enzymes required for the oxidation of pyruvate & fatty acids
A & D are true
Which of these are TRUE statements? A) The number and location of mitochondria within a cell can change, depending on both the cell type and the amount of energy required. B) The inner mitochondrial membrane contains porins, which allow pyruvate to enter for use in the citric acid cycle. C) The inner mitochondrial membrane is actually a series of discrete, flattened, membrane-enclosed compartments called cristae, similar to what is seen in the Golgi apparatus. D) The intermembrane space of the mitochondria is chemically equivalent to the cytosol with respect to pH and the small molecules present.