MICRO test 2

55. How many molecules of NADPH are needed to reduce one molecule of carbon dioxide to carbohydrate by oxygenic phototrophs during the dark reactions of photosynthesis? A. 2 B. 3 C. 4 D. 10-12

A. 2

10. The net gain of ATP per molecule of glucose metabolized anaerobically via the Embden-Meyerhoff pathway in prokaryotes is A. 2. B. 36. C. 38. D. 85.

A. 2.

17. Cells carry out three major types of work; which of the following involves the synthesis of macromolecules as well as the breakdown of substances for their energy? A. Chemical work. B. Transport work. C. Mechanical work. D. None of these.

A. Chemical work.

21. __________ is a measure of the randomness or disorder of a system. A. Entropy B. Enthalpy C. Free energy D. Synergy

A. Entropy

28. Differences between mitochondrial and E. coli electron transport chains include the following: A. The E. coli chain contains a different array of cytochromes. B. The fundamental principles on which they operate are different. C. Higher P/O values are observed in E. coli. D. The electron transport change does not involve membranes in E. coli.

A. The E. coli chain contains a different array of cytochromes.

20. In the TCA cycle, two carbons in the form of __________ are added to oxaloacetate at the start of the cycle. A. acetyl-CoA B. ethanol C. carbon dioxide D. methanol

A. acetyl-CoA

54. If an enzyme consists of a protein component and a non-protein component, the protein component is referred as the A. apoenzyme. B. coenzyme. C. holoenzyme. D. prosthetic group.

A. apoenzyme.

30. A reaction that releases energy is __________. A. exergonic B. endergonic C. impossible D. none of the choices

A. exergonic

22. The __________ law of thermodynamics states that energy can be neither created nor destroyed. A. first B. second C. third D. fourth

A. first

34. The __________ is the electron donor in a redox reaction. A. reductant B. oxidant C. enzyme D. product

A. reductant

54. How many molecules of ATP are needed to reduce one molecule of carbon dioxide to carbohydrate by oxygenic phototrophs during the dark reactions of photosynthesis? A. 2 B. 3 C. 4 D. 10-12

B. 3

30. The theoretical maximum net gain of ATP per molecule of glucose metabolized aerobically in eukaryotes is A. 2. B. 32. C. 38. D. 85.

B. 32.

26. __________ is the total energy change that accompanies a chemical reaction. A. Entropy B. Enthalpy C. Free energy D. Synergy

B. Enthalpy

18. Cells carry out three major types of work; which of the following involves nutrient uptake and waste elimination? A. Chemical work. B. Transport work. C. Mechanical work. D. None of these.

B. Transport work.

27. For the reaction A + B C + D, the equilibrium constant (Keq) is defined as A. [A][B]/[C][D]. B. [C][D]/[A][B]. C. [A][D]/[B][C]. D. [B][C]/[A][D].

B. [C][D]/[A][B].

59. The energy required to bring the substrates of a reaction together in the correct way to reach the transition state is called A. free energy. B. activation energy. C. enthalpy. D. entropy.

B. activation energy.

50. The substrate of an enzyme binds at the A. affinity site. B. active site. C. determinative site. D. reaction site.

B. active site.

47. Fatty acids are metabolized by the __________ pathway. A. alpha-oxidation B. beta-oxidation C. gamma-oxidation D. delta-oxidation

B. beta-oxidation

24. The amount of heat energy needed to raise 1 gram of water from 14.5C to 15.5C is called a(n) A. joule. B. calorie. C. erg. D. thermal unit.

B. calorie.

56. A(n) _______________ increases the rate of a reaction without being permanently altered by the reaction. A. catalyzer B. catalyst C. enzyme D. rate increaser

B. catalyst

52. A nonprotein component of an enzyme that is loosely attached to the protein component is referred to as a(n) A. apoenzyme. B. coenzyme. C. holoenzyme. D. prosthetic group.

B. coenzyme.

61. In the process of __________, ATP is synthesized when excited electrons from chlorophyll P700 pass through a series of electron carriers then return to chlorophyll P700. A. photosynthesis B. cyclic photophosphorylation C. acyclic photophosphorylation D. noncyclic photophosphorylation

B. cyclic photophosphorylation

32. An chemical reaction that requires an input of energy in order to proceed is __________. A. exergonic B. endergonic C. impossible D. one of the choices

B. endergonic

64. When the end product of a pathway inhibits catalysis of the first step of that pathway, this phenomenon is called A. reversible covalent modification. B. feedback inhibition. C. metabolic channeling. D. non-competitive inhibition.

B. feedback inhibition.

35. In aerobic conditions, it takes __________ sugar to produce the same amount of ATP when compared to anaerobic conditions. A. more B. less C. the same amount of

B. less

62. In metabolic channeling, the regulation of metabolic pathways is controlled by the __________ of metabolites and enzymes involved in the pathway. A. amount B. location C. activity D. all of the choices

B. location

55. If all available enzyme molecules are binding substrate and converting it to produce as rapidly as possible, the reaction is said to be proceeding at __________ velocity. A. terminal B. maximal C. optimal D. infinite

B. maximal

32. Mitochondrial electron transport takes place A. on the outer mitochondrial membrane. B. on the inner mitochondrial membrane. C. in the fluid matrix of the mitochondria. D. on the outer mitochondrial membrane and on the inner mitochondrial membrane.

B. on the inner mitochondrial membrane.

33. The __________ is the electron acceptor in a redox reaction. A. reductant B. oxidant C. enzyme D. product

B. oxidant

35. The standard reduction potential of a redox reaction is a measure of the tendency of the __________ to __________ electrons. A. reductant; gain B. reductant; lose C. oxidant; gain D. oxidant; lose

B. reductant; lose

31. Production of ATP using the energy liberated when electrons from reduced chemical bonds are passed through the electron transport system is generally referred to as __________. A. chemiosmotic B. respiration C. substrate-level D. conformational change

B. respiration

23. The __________ law of thermodynamics states that physical and chemical processes occur in such a way that randomness (disorder) increases to a maximum. A. first B. second C. third D. fourth

B. second

67. In a branched pathway with many end products, an abundance of one of the end products will usually inhibit A. the first step in the set of pathways. B. the first committed step in the branch of the pathway leading to the production of that particular product. C. the last step before the branch leading to the production of that particular end product. D. the last step in the production of that particular product.

B. the first committed step in the branch of the pathway leading to the production of that particular product.

11. The net gain of ATP per molecule of glucose metabolized to pyruvate using Entner-Doudoroff pathway is A. 4. B. 2. C. 1. D. 0.

C. 1.

14. The most common pathway for conversion of glucose to pyruvate is A. Entner-Doudoroff. B. Pentose phosphate. C. Embden-Meyerhoff. D. mixed acid fermentation.

C. Embden-Meyerhoff.

19. Cells carry out three major types of work; which of the following involves energy for cell motility and the movement of structures within cells? A. Chemical work. B. Transport work. C. Mechanical work. D. None of these.

C. Mechanical work.

34. The number of ATP molecules generated per atom of oxygen that is reduced when electrons are passed from NADH or reduced FAD (FADH) to O2 is called the A. utilization ratio. B. energy yield. C. P/O ratio. D. phosphorylation coefficient.

C. P/O ratio.

29. Which of the following is NOT true regarding ATP synthases? A. They require proton motive force to make ATP. B. They span the inner membrane of mitochondria. C. The proton flow is outward during ATP synthesis. D. The subunits of ATP synthase undergo conformational changes during ATP production.

C. The proton flow is outward during ATP synthesis.

33. In higher eukaryotes, most aerobically generated ATP is produced by A. glycolysis. B. the TCA cycle. C. a membrane bound proton translocating ATP synthase during oxidative phosphorylation. D. all of these generate equal amounts of ATP.

C. a membrane bound proton translocating ATP synthase during oxidative phosphorylation.

16. The pyruvate dehydrogenase complex oxidizes and cleaves pyruvate to form one CO2 and A. lactate. B. isocitric acid. C. acetyl-CoA. D. succinyl-CoA.

C. acetyl-CoA.

57. Enzymes function as catalysts by A. bringing the substrates together at the active site, in effect concentrating them. B. bringing the substrates together at the active site correctly oriented for the reaction. C. bringing the substrates together at the active site, in effect concentrating them and bringing the substrates together at the active site correctly oriented for the reaction. D. none of the choices

C. bringing the substrates together at the active site, in effect concentrating them and bringing the substrates together at the active site correctly oriented for the reaction.

19. In the TCA cycle, two carbons are removed from citric acid in the form of __________, thereby regenerating oxaloacetate to complete the cycle. A. acetyl-CoA B. ethanol C. carbon dioxide D. methanol

C. carbon dioxide

58. Enzymes catalyze a reaction by A. decreasing the amount of energy released by the reaction. B. increasing the amount of energy released by the reaction. C. decreasing the activation energy of the reaction. D. increasing the activation energy of the reaction.

C. decreasing the activation energy of the reaction.

49. The most specific term usually used to describe a substance in a biological system that increases the rate of a reaction without being permanently changed by the reaction is a(n) A. catalyzer. B. catalyst. C. enzyme. D. rate increaser.

C. enzyme.

28. The change in __________ is the amount of energy in a system that is available to do work. A. entropy B. enthalpy C. free energy D. synergy

C. free energy

51. A complete enzyme that consists of a protein component and a nonprotein component is called a(n) A. apoenzyme. B. heteroenzyme. C. holoenzyme. D. multienzyme.

C. holoenzyme.

1. The sum total of all chemical reactions occurring in a cell is called A. anabolism. B. catabolism. C. metabolism. D. none of the choices

C. metabolism.

66. In allosteric regulation, effector molecules usually bind A. reversibly and covalently. B. irreversibly and covalently. C. reversibly and noncovalently. D. irreversibly and noncovalently.

C. reversibly and noncovalently.

13. The synthesis of ATP from ADP and Pi, when coupled with an exergonic chemical reaction is called __________ phosphorylation. A. chemiosmotic B. oxidative C. substrate-level D. conformational change

C. substrate-level

63. Metabolic channeling involves the localization of __________ in different parts of a cell in order to influence the activity of metabolic pathways. A. activators B. repressors C. substrates and enzymes D. inhibitors

C. substrates and enzymes

48. During breakdown of fatty acids, carbons are removed __________ at a time with each turn of the cycle, and two carbon units are released as __________. A. one; carbon dioxide B. one; methane C. two; acetyl-CoA D. two; ethanol

C. two; acetyl-CoA

56. How many quanta of light are needed to reduce one molecule of carbon dioxide to carbohydrate during photosynthesis? A. 2 B. 3 C. 4 D. 10-12

D. 10-12

53. Which of the following may be used as sources of energy by chemolithotrophs? A. Hydrogen gas. B. Reduced nitrogen compounds. C. Reduced sulfur compounds. D. All of the choices.

D. All of the choices.

61. Which of the following is a reason for metabolic regulation? A. Maintain cell components at appropriate levels. B. Conserve materials. C. Ensure efficient use energy stores. D. All of the choices.

D. All of the choices.

37. Which of the following is used as an electron carrier by living organisms? A. NAD+ B. NADP+ C. ubiquinone D. all of the choices

D. all of the choices

39. Which of the following can be used as electron acceptors during anaerobic respiration? A. nitrate B. sulfate C. carbon dioxide D. all of the choices

D. all of the choices

41. Which of the following is not true about enzymes? A. Enzymes are catalysts that speed up reactions. B. Enzymes are proteins that can be denatured by changes in pH or temperature. C. Enzymes are highly specific for the substrates they react with and catalyze only one or a limited set of possible reactions with those substrates. D. all of the choices

D. all of the choices

60. In the process of noncyclic photophosphorylation A. water is split to form oxygen gas. B. electrons from water flow through electron transport chains resulting in synthesis of ATP and NADPH. C. photosystems I and II are both required. D. all of the choices

D. all of the choices

65. Enzyme activity can be controlled by A. allosteric regulation. B. covalent modification. C. feedback (end product) inhibition. D. all of the choices

D. all of the choices

12. The pentose phosphate pathway produces A. CO2. B. NADPH. C. glyceraldehyde 3-phosphate. D. all of the choices.

D. all of the choices.

50. Amino acids are processed first by the removal of the amino group through A. deamination. B. transamination. C. phosphorolytic cleavage. D. deamination or transamination

D. deamination or transamination

21. The major function(s) of the TCA cycle is(are) A. energy production. B. provision of carbon skeletons for biosynthesis of cell components. C. electron transport. D. energy production and provision of carbon skeletons for biosynthesis of cell components.

D. energy production and provision of carbon skeletons for biosynthesis of cell components.

40. Electron transport molecules that only transfer electrons include A. ubiquinone. B. NADP. C. FAD. D. ferredoxin.

D. ferredoxin.

62. Photosynthetic electron transport in cyanobacteria takes place A. on the plasma membrane. B. in the chloroplast. C. in the cytoplasm. D. on the thylakoid membranes.

D. on the thylakoid membranes.

53. The nonprotein component of an enzyme that is firmly attached to the protein is called a(n) A. apoenzyme. B. coenzyme. C. holoenzyme. D. prosthetic group.

D. prosthetic group.

15. The TCA cycle generates all of the following from each acetyl-CoA molecule oxidized except A. three NADH molecules. B. two CO2 molecules. C. one FADH2 molecule. D. two ATP or GTP molecules.

D. two ATP or GTP molecules.

48. Enzymes are usually named based on A. the substrates they act on. B. their molecular structure. C. the type of reaction they catalyze. D. all of the choices. E. the substrates they act on and the type of reaction they catalyze.

E. the substrates they act on and the type of reaction they catalyze.