Eukaryotic Final: Ch 14

44. Which of the following statements about the mitochondrion is TRUE? (a) The number and location of mitochondria within a cell can change, depending on the 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 matrix with respect to pH and the small molecules present.

(a) The number and location of mitochondria within a cell can change, depending on the both the cell type and the amount of energy required (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 matrix with respect to pH and the small molecules present.

Electron-transfer reactions occur rapidly. Which of the following statements best describes how the diffusion of ubiquinone is controlled in order to ensure its proximity to the other enzyme complexes? (a) Ubiquinone is anchored directly in the inner mitochondrial membrane via its hydrocarbon tail, and can only diffuse laterally. (b) Ubiquinone is present at high concentrations, minimizing the impact of diffusion on the electron-transport chain. (c) Ubiquinone becomes covalently attached to the other enzyme complexes. (d) The intermembrane space in the mitochondrion is relatively small, and therefore the random diffusion of these molecules is not a problem

(a) Ubiquinone is anchored directly in the inner mitochondrial membrane via its hydrocarbon tail, and can only diffuse laterally.

43. 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

(a) chemiosmotic coupling

In stage 1 of photosynthesis, a proton gradient is generated and ATP is synthesized. Where do protons become concentrated in the chloroplast? (a) thylakoid space (b) stroma (c) inner membrane (d) thylakoid membrane

(a) thylakoid space

45. NADH contains a high-energy bond that, when cleaved, donates a pair of electrons to the electron-transport chain. What are the immediate products of this bond cleavage? (a) NAD+ + OH-(b) NAD+ + H-(c) NAD- + H+(d) NAD + H

(b) NAD+ + H-

49. Which of the following statements about the proton motive force across the mitochondrial inner membrane is true? (a) Because the electrons in NADH are at a higher energy than the electrons in reduced ubiquinone, the NADH dehydrogenase complex can pump more protons than can the cytochrome b-c1 complex. (b) The pH in the mitochondrial matrix is higher than the pH in the intermembrane space. (c) The proton concentration gradient and the membrane potential across the inner mitochondrial membrane tend to work against each other in driving protons from the intermembrane space into the matrix. (d) Compared with proton concentration across the inner mitochondrial membrane, contribution from the membrane potential to the total proton-motive force is negligible.

(b) The pH in the mitochondrial matrix is higher than the pH in the intermembrane space.

54. Which of the following statements about electron carriers of the mitochondrion is false? (a) Ubiquinone is associated with the inner mitochondrial membrane with its long hydrocarbon tail. (b) Ubiquinone can transfer only one electron in each cycle. (c) The iron-sulfur centers in NADH dehydrogenase are relatively poor electron acceptors. (d) Cytochrome oxidase binds O2 using an iron-heme group, where four electrons are shuttled one at a time.

(b) Ubiquinone can transfer only one electron in each cycle.

In the electron-transport chain in chloroplasts, ________-energy electrons are taken from __________. (a) high; H2O. (b) low; H2O. (c) high; NADPH. (d) low; NADPH. b

(b) low; H2O.

The photosystems in chloroplasts contain hundreds of chlorophyll molecules, most of which are part of _______________. (a) plastoquinone. (b) the antenna complex. (c) the reaction center. (d) the ferredoxin complex.

(b) the antenna complex

51. The F1 portion of the mitochondrial ATP synthase comprises several different protein subunits. Which subunit has a binding site for ADP + Pi and catalyzes the synthesis of ATP as a result of a conformational change? (a) α(b) β(c) δ(d) ε

(b) β

52. NADH and FADH2 carry high-energy electrons that are used to power the production of ATP in the mitochondria. These cofactors are generated during glycolysis, the citric acid cycle, and the fatty acid oxidation cycle. Which molecule below can produce the most ATP? Explain your answer. (a) NADH from glycolysis (b) FADH2 from the fatty acid cycle (c) NADH from the citric acid cycle (d) FADH2 from the citric acid cycle

(c) NADH from the citric acid cycle

47. 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.

(c) O2 is reduced to H2O.

53. Which of the following statements about redox potential is true? (a) Only compounds with negative redox potentials can donate electrons to other compounds under standard conditions. (b) Compounds that donate one electron have higher redox potentials than those of compounds that donate two electrons. (c) The δE′0 of a redox pair does not depend on the concentration of each member of the pair. (d) The free-energy change, δG, for an electron transfer reaction does not depend on the concentration of each member of a redox pair.

(c) The δE′0 of a redox pair does not depend on the concentration of each member of the pair.

Which of the following is not an electron carrier that participates in the electron-transport chain? (a) cytochrome (b) quinone (c) rhodopsin (d) copper ion

(c) rhodopsin

Which of the following statements is true? (a) Ubiquinone is a small, hydrophobic protein containing a metal group that acts as an electron carrier. (b) A 2Fe2S iron-sulfur center carries one electron, whereas a 4Fe4S center carries two. (c) Iron-sulfur centers generally have a higher redox potential than do cytochromes. (d) Mitochondrial electron carriers with the highest redox potential generally contain copper ions and/or heme groups.

(d) Mitochondrial electron carriers with the highest redox potential generally contain copper ions and/or heme groups.

Stage 2 of photosynthesis, sometimes referred to as the dark reactions, involves the reduction of CO2 to produce organic compounds such as sucrose. What cofactor is the electron donor for carbon fixation? (a) H2O (b) NADH (c) FADH2 (d) NADPH

(d) NADPH

48. 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 oxidase complex

(d) cytochrome oxidase complex

Photosynthesis is a process that takes place in chloroplasts and uses light energy to generate high-energy electrons, which are passed along an electron-transport chain. Where are the proteins of the electron-transport chain located in chloroplasts? (a) thylakoid space (b) stroma (c) inner membrane (d) thylakoid membrane

(d) thylakoid membrane

The ATP synthase found in chloroplasts is structurally similar to the ATP synthase in mitochondria. Given that ATP is being synthesized in the stroma, where will the F0 portion of the ATP synthase be located? (a) thylakoid space (b) stroma (c) inner membrane (d) thylakoid membrane

(d) thylakoid membrane

3. Which of the following drives the production of ATP from ADP and Pi by ATP synthase? A. A proton gradient B. A Na+ gradient C. Phosphorylation D. A K+ gradient

A. A proton gradient

13.Which of the following statements is true about the electron transport chain? A. Electrons start out at very high energy and lose energy at each transfer step. B. Electrons start out at very low energy and gain energy at each transfer step. C. Electrons gain and release energy as they move from one complex to another in the electron transport chain.

A. Electrons start out at very high energy and lose energy at each transfer step.

17.It is energetically favorable for protons to flow in which direction? A. From the intermembrane space to the mitochondrial matrix B. From the mitochondrial matrix to the intermembrane space C. From the mitochondrial matrix to the cytosol D. From the mitochondrial matrix to the endoplasmic reticulum

A. From the intermembrane space to the mitochondrial matrix

11.Which of the following is not a direct source of fuel for mitochondria? A. Glucose B. Pyruvate C. Fatty acids

A. Glucose

22. What is the ratio of ATP and ADP concentrations in the cytosol of a cell? A. High ATP/ADP ratio B. High ADP/ATP ratio

A. High ATP/ADP ratio

34. In the electron transport chain in chloroplasts, which molecule serves as the final electron acceptor? A. NADP+ B. NADH C. H2O D. O2

A. NADP+

33 .Stage 1 of photosynthesis is in large part equivalent to what? A. Oxidative phosphorylation B. The citric acid cycle C. Mitosis D. Glycolysis

A. Oxidative phosphorylation

35.Chlorophyll molecules absorb which color of light most strongly? A. Red B. Green C. Blue D. UV

A. Red

21. The proton gradient can drive the active transport of metabolites into and out of the mitochondrion. A. True B. False

A. True

29. Ubiquinone has a redox potential of +30 mV, while cytochrome c has a redox potential of +230 mV. In the electron transport chain, electrons flow from: A. Ubiquinone to cytochrome c. B. Cytochrome c to ubiquinone.

A. Ubiquinone to cytochrome c.

26. As electrons move through the electron transport chain, they are passed from: A. a carrier molecule of lower electron affinity to a carrier molecule of higher electron affinity. B. a carrier molecule of higher electron affinity to a carrier molecule of lower electron affinity.

A. a carrier molecule of lower electron affinity to a carrier molecule of higher electron affinity.

24. Cellular respiration: A. is more efficient at generating energy than a gasoline-powered engine. B. is less efficient at generating energy than a gasoline engine C. operates at about the same efficiency as a gasoline-powered engine D. cannot be compared to the efficiency of a gasoline engine.

A. is more efficient at generating energy than a gasoline-powered engine.

4. In the electron transport chain, as electrons move along a series of carriers, they release energy that is used to: A. pump protons across a membrane. B. phosphorylate ADP to form ATP. C. split water into protons and oxygen.

A. pump protons across a membrane

50. Which of the following types of ion movement might be expected to require co-transport of protons from the intermembrane space to the matrix, since it could not be driven by the membrane potential across the inner membrane? (Assume that each ion being moved is moving against its concentration gradient.) (a) import of Ca2+ into the matrix from the intermembrane space (b) import of acetate ions into the matrix from the intermembrane space (c) exchange of Fe2+ in the matrix for Fe3+ in the intermembrane space (d) exchange of ATP from the matrix for ADP in the intermembrane space

B). Import of acetate ions into the matrix from the intermembrane space.

40. What provides the fuel to convert CO2 into sugars in chloroplasts? A. A proton gradient across a membrane B. ATP and NADPH generated in the photosynthetic light reactions C. ATP generated in cellular respiration

B. ATP and NADPH generated in the photosynthetic light reactions

20. What occurs when ATP synthase pumps H+ across a membrane against the electrochemical proton gradient? A. ATP synthase transports Na+ in the opposite direction across the membrane B. ATP synthase cleaves ATP to form ADP and Pi C. ATP synthase catalyzes the formation of ATP from ADP and Pi

B. ATP synthase cleaves ATP to form ADP and Pi

36. When a chlorophyll molecule captures light energy, what form does the energy take? A. New electrons added to the molecule B. Excited electrons C. Chemical bond formation with a molecule in the reaction center of the photosystem

B. Excited electrons

23. Why does a single molecule of NADH result in the production of more ATP molecules than a single molecule of FADH2 via oxidative phosphorylation? A. NADH donates more electrons to the chain. B. FADH2 feeds its electrons into the electron transport chain further along the chain. C. FADH2 is less likely than NADH to participate in the electron transport chain.

B. FADH2 feeds its electrons into the electron transport chain further along the chain.

10.In a eukaryotic cell, where are most of the proteins for the electron transport chain located? A. In the plasma membrane B. In the mitochondrial inner membrane C. In the mitochondrial outer membrane D. In the ER membrane

B. In the mitochondrial inner membrane

15. In mitochondria, what is the final electron acceptor in the electron transport chain? A. Carbon dioxide (CO2) B. Molecular oxygen (O2) C. Water (H2O) D. NADH and FADH2

B. Molecular oxygen (O2)

27. Which of the following is true? A. NADH has a strong affinity for electrons and a positive redox potential. B. NADH has a weak affinity for electrons and a negative redox potential. C. NADH has a strong affinity for electrons and a negative redox potential. D. NADH has a weak affinity for electrons and a negative redox potential.

B. NADH has a weak affinity for electrons and a negative redox potential.

42. What electron acceptor allows an organism to completely break down organic molecules into CO2 and H2O and thereby release a large amount of energy that can be harnessed by the cell to do work? A. H2O B. O2 C. CO2 D. Pyruvate E. NAD+

B. O2

2. Which of the following processes involves a membrane? A. Substrate level phosphorylation B. Oxidative phosphorylation C. Citric acid cycle D. Directional movement of motor proteins

B. Oxidative phosphorylation

38. Which photosystem is able to boost electrons to the very high energy level needed to make NADPH from NADP+? A. Photosystem II B. Photosystem I C. Photosystem III D. Calvin cycle

B. Photosystem I

32. In chloroplasts the pigment chlorophyll donates electrons to an electron transport chain in the thylakoid membrane. A. False B. True

B. True

25. Which of the following statements is NOT true of electron transfer in the electron transport chain? A. Each electron transfer is an oxidation-reduction reaction. B. When an electron carrier accepts an electron, it becomes oxidized. C. NADH has a relatively low electron affinity.

B. When an electron carrier accepts an electron, it becomes oxidized.

28. NADH has a strong tendency to: A. accept electrons. B. donate electrons. C. either donate or accept electrons depending on the electrochemical proton gradient.

B. donate electrons.

16.The electron transport chain pumps protons: A. from the intermembrane space to the matrix. B. from the matrix to the intermembrane space. C. from the matrix to the cytosol. D. from the matrix to the endoplasmic reticulum

B. from the matrix to the intermembrane space.

18. When protons move down their electrochemical gradient into the mitochondrial matrix, they: A. produce NADH. B. produce ATP. C. consume ATP. D. they move electrons through the respiratory chain.

B. produce ATP

41. During very active periods of photosynthesis, the glyceraldehyde-3-phosphate generated by carbon fixation in the stroma is stored as: A. ATP. B. starch. C. glycogen. D. pyruvate.

B. starch

31. Photosynthesis allows plant to capture energy from sunlight to produce: A. CO2. B. sugars. C. chlorophyll. D. H2O.

B. sugars.

7.In mitochondria, with the complete breakdown of glucose, about how many molecules of ATP can be produced for each molecule of glucose oxidized? A. 2 B. 12 C. 30 D. 50

C. 30

1. What is the main chemical energy currency in cells? A. Glucose B. NADH D. High-energy electrons

C. ATP

6.Which of the following organisms do not have mitochondria in their cells? A. Plants B. Animals C. Bacteria D. Fungi

C. Bacteria

12.The electron transport chain accepts high-energy electrons from: A. ATP. B. pyruvate. C. NADH and FADH2. D. acetyl CoA.

C. NADH and FADH2.

39. When an electron is removed from the reaction center of photosystem II, how is the missing electron then replenished? A. With an electron from a sunlight B. With an electron from a hydrogen ion C. With an electron removed from water D. With an electron removed from photosystem I

C. With an electron removed from water

19. ATP synthase: A. can produce ATP but cannot break it down. B. can break down ATP but cannot produce it. C. can either produce or break down ATP depending on the magnitude of the electrochemical proton gradient. D. can transfer a phosphate group from its side chain to ADP.

C. can either produce or break down ATP depending on the magnitude of the electrochemical proton gradient.

14. The movement of electrons through the electron transport chain: A. consumes ATP. B. produces NADH. C. pumps protons across the inner mitochondrial membrane. D. pumps ATP across the inner mitochondrial membrane.

C. pumps protons across the inner mitochondrial membrane.

37. In photosynthesis, what drives generation of ATP by ATP synthase? A. The transfer of high-energy electrons to ATP synthase B. The phosphorylation of ATP synthase C. The absorption of a photon of light by an adjacent chlorophyll molecule D. A proton gradient across the thylakoid membrane

D. A proton gradient across the thylakoid membrane

8.Which of the following is NOT true of mitochondria? A. They are similar in size and shape to bacteria. B. They contain their own DNA and RNA. C. They contain an outer membrane, and inner membrane, and two internal compartments. D. They are replaced by chloroplasts in plants. E. Inside a cell, they are mobile, constantly changing shape and position.

D. They are replaced by chloroplasts in plants.

5. The organelles that produce ATP in eukaryotic cells: A. reproduce sexually. B. harbor eukaryotic-like biosynthetic machinery for making RNA. C. have a separate set of DNA that contains many of the same genes found in the nucleus. D. evolved from bacteria engulfed by ancestral cells billions of years ago.

D. evolved from bacteria engulfed by ancestral cells billions of years ago.

56. Cytochrome oxidase is an enzyme complex that uses metal ions to help coordinate the transfer of four electrons to O2. Which metal atoms are found in the active site of this complex?

iron and copper

30.When O2 accepts electrons in the electron transport chain, O2 becomes _______. A. oxidized B. reduced

reduced

9.The outer membrane of a mitochondrion is permeable to all small molecules, including small proteins. A. True B. False

true