1.NDC-Biochemistry-Week-01 (14-09-2014)

Narayana Dental PG Coaching - Biochemistry Week-01 Test (14-09-2014 1. A bacterial mutant grows normally at 32°C but at 42°C accumulates short segments of newly synthesized DNA. Which one of the following enzymes is most likely to be defective at the nonpermissive temperature (the higher temperature) in this mutant? (A) DNA primase (B) DNA polymerase (C) An exonuclease (D) An unwinding enzyme (helicase) (E) DNA ligase

(B) Northern blot (C) Western blot (D) Sanger technique (E) Southwestern blot 7. A 17-year-old male has large, prominent ears, elongated face, large testicles, hand flapping, low muscle tone, and mild mental retardation. Which type of mutation does his diagnosis represent? (A) Point (B) Insertion (C) Deletion (D) Mismatch (E) Silent

2.An RNA produced from a fragment of DNA has the sequence of AAUUGGCU. The sequence of the nontemplate strand in the DNA that gave rise to this sequence is which one of the following? (A) AGCCAATT (B) AAUUGGCU (C) AATTGGCT (D) TTAACCGA (E) UUAACCGA

8.A young black man was brought to the emergency room (ER) due to severe pain throughout his body. He had been exercising vigorously when the pain started. He has had such episodes about twice a year for the past 10 years. An analysis of the blood shows a reduced blood cell count (anemia), and odd- looking red blood cells that were no longer concave and looked like an elongated sausage. The type of mutation leading to this disorder is best described as which one of the following? (A) Insertion (B) Deletion (C) Missense (D) Nonsense (E) Silent

3.Which one of the following changes in the coding region of an mRNA (caused by a point mutation) would result in translation of a protein identical to the normal protein? (A) UCA → UAA (B) UCA → CCA (C) UCA → UCU (D) UCA → ACA (E) UCA → GCA 4. Your diabetic patient is using the short-acting insulin lispro to control his blood glucose levels. Lispro is a synthetic insulin formed by reversing the lysine and proline residues on the C-terminal end of the B-chain. This allows for more rapid absorption of insulin from the injection site. The engineering of this drug is an example of which of the following technologies? (A) Polymorphism (B) DNA fingerprinting (C) Site-directed mutagenesis (D) Repressor binding to a promoter (E) PCR

9. A woman has been complaining of a burning sensation when urinating, and a urine culture demonstrated a bacterial infection. The physician placed the woman on ciprofloxacin. Ciprofloxacin will be effective in eliminating the bacteria because it interferes with which one of the following processes? (A) mRNA splicing (B) Initiation of protein synthesis (C) Elongation of protein synthesis (D) Nucleotide excision repair (E) DNA replication 10. A 72-year-old man acquired a bacterial infection in the hospital while recuperating from a hip replacement surgery. The staph infection was resistant to a large number of antibiotics, such as amoxicillin, methicillin, and vancomycin, and was very difficult to treat. The bacteria acquired its antibiotic resistance owing to which one of the following? Choose the one best answer. (A) Spontaneous mutations in existing genes (B) Large deletions of the chromosome (C) Transposon activity (D) Loss of energy production (E) Alterations in the membrane structure

5. For the synthesis of lispro insulin (as described in the previous question), which one of the following changes in the coding for the B-chain would be required? (A) CAAAAA to AAAAAC (B) CCTAAT to AAACTC (C) CCGAAG to AAACCA (D) AAACCA to CCGAAG (E) AAGCCT to AAACCC 6. A thin, emaciated 25-year-old male presents with purple plaques and nodules on his face and arms, coughing, and shortness of breath. In order to diagnose the cause of his problems most efficiently, you would order which one of the following types of tests? (A) Southern blot

11. A 42-year-old man is placed on a two drug regimen to prevent the activation of the tuberculosis bacteria, as

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Narayana Dental PG Coaching - Biochemistry Week-01 Test (14-09-2014 his tuberculin skin test (PPD) was positive, but he shows no clinical signs of tuberculosis, and his chest X-ray is negative. One of the drug’s mechanism of action is to inhibit which one of the following enzymes? (A) DNA polymerase (B) RNA polymerase (C) Peptidyl transferase (D) Initiation factor 1 of protein synthesis (IF-1) (E) Telomerase

16. Consider the section of the TCA cycle in which isocitrate is converted to fumarate. This segment of the TCA cycle can be best described by which one of the following? (A) These reactions yield 5 moles of high energy phosphate bonds per mole of isocitrate. (B) These reactions require a coenzyme synthesized in the human from niacin (nicotinamide). (C) These reactions are catalyzed by enzymes located solely in the mitochondrial membrane. (D) These reactions produce 1 mole of CO2 for every mole of isocitrate oxidized. (E) These reactions require GTP to drive one of the reactions.

12. A 47-year-old woman, who has been on kidney dialysis for the past 7 years, has developed jaundice, fatigue, nausea, a lowgrade fever, and abdominal pain. A physical examination indicates a larger-than-normal liver, and blood work demonstrates elevated levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT). The physician places the patient on two drugs, one of which is a nucleoside analog, geared to inhibit DNA and RNA syntheses. The primary function of the other drug is to do which one of the following? (A) Inhibit DNA repair in infected cells (B) Enhance the rate of the elongation phase of protein synthesis (C) Reduce the rate of initiation of protein synthesis (D) Inhibit ribosome formation (E) Promote ribosome formation

17. In the TCA cycle, a role for thiamine pyrophosphate is which one of the following? (A) To accept electrons from the oxidation of pyruvate and αketoglutarate (B) To accept electrons from the oxidation of isocitrate (C) To form a covalent intermediate with the α-carbon of αketoglutarate (D) To form a thioester with the sulfhydryl group of CoASH (E) To form a thioester with the sulfhydryl group of lipoic acid 18. Which one of the following is a property of pyruvate dehydrogenase? (A) The enzyme contains only one polypeptide chain. (B) The enzyme requires thiamine pyrophosphate as a cofactor. (C) The enzyme produces oxaloacetate from pyruvate. (D) The enzyme is converted to an active form by phosphorylation. (E) The enzyme is activated when NADH levels increase.

13. Of the total energy available from the oxidation of acetate, what percentage is transferred via the TCA cycle to NADH, FADH2, and GTP? (A) 38% (B) 42% (C) 81% (D) 86% (E) 100%

19. Which one of the following components of the electron transport chain only accepts electrons, and does not donate them? (A) Cytochrome b (B) Oxygen (C) Coenzyme Q (D) FMN (E) Cytochrome C1

14. What percentage of the energy available from the oxidation of acetate is converted to ATP? (A) 3% (B) 30% (C) 40% (D) 85% (E) 100%

20. Which one of the following tissues of the eye relies almost solely on anaerobic metabolism instead of the TCA/electron transport cycle? (A) Cornea (B) Lens (C) Ciliary muscle (D) Retina (E) All of the tissues of the eye use only anaerobic glycolysis as an energy source.

15. A genetic mutation caused the cellular concentration of an enzyme to increase 100- fold for a biochemical reaction. Therefore, the equilibrium constant for the reaction catalyzed by the enzyme would change in which one of the following ways? (A) It would decrease two-fold. (B) It would remain the same. (C) It would increase in proportion to the enzyme concentration. (D) It would change inversely with the enzyme concentration. (E) It would decrease 100-fold.

21. A patient is undergoing an appendectomy under general anesthesia (succinylcholine and an inhaled anesthetic) when she begins to develop muscle rigidity, tachycardia, and hyperthermia. Which of the following best describes the mechanism of this process?

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Narayana Dental PG Coaching - Biochemistry Week-01 Test (14-09-2014 (A) Uncoupling of electron transport and phosphorylation (B) Inhibition of NADH dehydrogenase (C) Inhibition of cytochrome oxidase (D) Inhibiting an adequate supply of ADP (E) Combining with coenzyme Q

D.

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28. The most abundant protein present in body is A. Globulin B. Albumin C. Collagen D. Hemoglobin

22. A patient is in septic shock and his tissues are poorly perfused and oxygenated. The major end product of glucose metabolism in these tissues will be an accumulation of which one of the following? (A) Pyruvate (B) Acetyl-CoA (C) Lactate (D) Urea (E) Citrate

29. The up of A. B. C. D.

genome of the bacteriophage phi x 174 is made Single stranded linear RNA Double stranded circular DNA Single stranded circular DNA Double stranded linear RNA

30. Eukaryotic chomosomal DNA is most condensed during which phase of the cell cycle 1. G0 2. S 3. G1 4. Mitosis

23. Which one of the following cell types cannot utilize the TCA cycle or electron transport chain? (A) Brain (B) Red blood cells (C) Liver (D) Kidney (E) Heart

31. The extent of DNA synthesis in a cell could most specifically be determined by measuring the incorporation of radiolabeled: A. leucine. B. phosphate. C. ribose D. thymidine E. uracil

24. Metformin is the standard first-line oral medication for Type 2 diabetes. The use of the drug has the potential side effect of lactic acidosis. Which of the following explains why this lactic acid buildup is rarely seen clinically? (A) The red blood cells utilize the lactate as fuel. (B) The renal cell utilizes the lactate as fuel. (C) The cardiac muscle cells utilize the lactate as fuel. (D) The large, voluntary muscle groups utilize the lactate as fuel. (E) The lactate directly enters the TCA cycle to be oxidized.

32. A 10-year-old girl is brought to the dermatologist byher parents. She has many freckles on her face, neck, arms, and hands, and the parents report that she is unusually sensitive to sunlight. Two basal cell carcinomas are identified on her face. Which of the following processes is most likely to be defective in this patient? A. Repair of double-strand breaks. B. Removal of mismatched bases from the 3'-end of Okazaki fragments. C. Removal of pyrimidine dimers from DNA. D. Removal of uracil from DNA

25. An environmentalist attempted to live in a desolate forest for 6 months, but had to cut his experiment short when he began to suffer from bleeding gums, some teeth falling out, and red spots on the thighs and legs. This individual is suffering from an inability to properly synthesize which one of the following proteins? (A) Myoglobin (B) Hemoglobin (C) Collagen (D) Insulin (E) Fibrillin

33. A mature MRNA could be longer than its precursor pre mRNA a due to A. 5’capping B. Poly A tailing C. Splicing D. None

26 Type of collage found in hyaline cartilage is A. Type I B. Type II C. Type III D. Type IV

34. The compound that consists of ribose linked by an N-glycosidic bond to N-9 of adenine is: A) a deoxyribonucleoside. B) a purine nucleotide. C) a pyrimidine nucleotide. D) adenosine monophosphate. E) adenosine.

27. All of the following types of collagen EXCEPT one are present in cartilage A. 2 B. 4 C. 6

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Narayana Dental PG Coaching - Biochemistry Week-01 Test (14-09-2014 35. Which one of the following is true of the pentoses found in nucleic acids? A) C-5 and C-1 of the pentose are joined to phosphate groups. B) C-5 of the pentose is joined to a nitrogenous base, and C1 to a phosphate group. C) The bond that joins nitrogenous bases to pentoses is an O-glycosidic bond. D) The pentoses are always in the -furanose forms. E) The straight-chain and ring forms undergo constant interconversion.

A) covalent bonds between the 3' end of one strand and the 5' end of the other. B) hydrogen bonding between the phosphate groups of two side-by-side strands. C) hydrogen bonds between the riboses of each strand. D) nonspecific base-stacking interaction between two adjacent bases in the same strand. E) ribose interactions with the planar base pairs. 42. In nucleotides and nucleic acids, syn and anti conformations relate to: A) base stereoisomers. B) rotation around the phosphodiester bond. C) rotation around the sugar-base bond. D) sugar pucker. E) sugar stereoisomers.

36. The nucleic acid bases: A) absorb ultraviolet light maximally at 280 nm. B) are all about the same size. C) are relatively hydrophilic. D) are roughly planar. E) can all stably base-pair with one another.

43. B-form DNA in vivo is a ________-handed helix, _____ Å in diameter, with a rise of ____ Å per base pair. A) left; 20; 3.9 B) right; 18; 3.4 C) right; 18; 3.6 D) right; 20; 3.4 E) right; 23; 2.6

37. Which of the following statements concerning the tautomeric forms of bases such as uracil is correct? A) The all-lactim form contains a ketone group. B) The lactam form contains an alcohol group. C) The lactam form predominates at neutral pH. D) They are geometric isomers. E) They are stereoisomers.

44. In DNA sequencing by the Sanger (dideoxy) method: A) radioactive dideoxy ATP is included in each of four reaction mixtures before enzymatic synthesis of complementary strands. B) specific enzymes are used to cut the newly synthesized DNA into small pieces, which are then separated by electrophoresis. C) the dideoxynucleotides must be present at high levels to obtain long stretches of DNA sequence. D) the role of the dideoxy CTP is to occasionally terminate enzymatic synthesis of DNA where Gs occur in the template strands. E) the template DNA strand is radioactive.

38. In the Watson-Crick model for the DNA double helix (B form) the A–T and G–C base pairs share which one of the following properties? A) The distance between the two glycosidic (base-sugar) bonds is the same in both base pairs, within a few tenths of an angstrom. B) The molecular weights of the two base pairs are identical. C) The number of hydrogen bonds formed between the two bases of the base pair is the same. D) The plane of neither base pair is perpendicular to the axis of the helix. E) The proton-binding groups in both base pairs are in their charged or ionized form.

45. Which of the following is attached to the transfer RNA (tRNA)? A. DNA B. ribosome C. amino acid D. nucleic acid

39. Chargaff's rules state that in typical DNA: A) A = G. B) A = C. C) A = U. D) A + T = G + C. E) A + G = T + C.

46. Which of the following is not part of protein synthesis? A. replication B. translation C. transcription

40. In the Watson-Crick model of DNA structure (now called B-form DNA): A) a purine in one strand always hydrogen bonds with a purine in the other strand. B) A–T pairs share three hydrogen bonds. C) G–C pairs share two hydrogen bonds. D) the 5' ends of both strands are at one end of the helix. E) the bases occupy the interior of the helix.

47. The codon is located on the A. mRNA. B. tRNA. C. rRNA. D. DNA.

41. The double helix of DNA in the B-form is stabilized by:

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Narayana Dental PG Coaching - Biochemistry Week-01 Test (14-09-2014 C. D. E.

48. In the RNA molecule, which nitrogen base is found in place of thymine? A. guanine B. cytosine C. thymine D. uracil

Transfer RNA bonds to a specific codon. Amino acids are bonded together. RNA moves from the nucleus to the cytoplasm.

57. The correct order of these events is A. B E A C D B. D A E C B C. B C E D A D. C B A E D

49. During the process of transcription, which of the following is produced? A. H2O B. ATP C. mRNA D. DNA

58. What is the complementary messenger-RNA sequence for the DNA sequence shown below?

50. The actual site of protein synthesis is the A. nucleus. B. mitochondrion. C. chloroplast. D. ribosome.

A. B. C. D.

51. If the DNA template reads “ATA”, then which of the following would be the corresponding sequence on the mRNA? A. UAU B. ATA C. TUT D. UCU

C-A-A-G-G-U G-T-T-C-C-A G-U-U-C-C-A C-A-A-G-G-T Use the diagram below for Questions 59-61

52. The genetic code is based upon the reading of how many bases at a time? A. one B. two C. three D. four

59. Which processes occur in the nucleus? A. 1 and 2 B. 2 and 3 C. 3 and 4 D. 4 and 5 60. Process 2 is known as A. replication B. mutation C. transcription D. translation

53. Amino acids are held together by __?__ bonds. A. hydrogen B. peptide C. ionic D. high energy

61. What is the product of process 3? A. a strand of DNA B. two complementary strands of DNA C. a strand of RNA D. a chain of amino acids

54. How many codons are needed to specify three amino acids? A.3 B.6 C.9 D.12

Use the diagram below for Questions 62-64

55. One similarity between DNA and messenger RNA molecules is that they both contain A. the same sugar B. genetic codes based on sequences of bases C. a nitrogenous base known as uracil D. double-stranded polymers 56. Some events that take place during the synthesis of a specific protein are listed below. A. Messenger RNA attaches to a ribosome. B. DNA serves as a template for RNA production.

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Narayana Dental PG Coaching - Biochemistry Week-01 Test (14-09-2014

62. Structure X was made in the A. nucleus B. cytoplasm C. lysosome D. vacuole 63. The process represented in the diagram is most closely associated with the cell organelle known as the A. nucleolus B. ribosome C. chloroplast D. mitochondrion

A. B. C. D.

64. Which amino acid would be transferred to the position of codon CAC? A. leucine B. glycine C. valine D. histdine

Replication Transcription Translation Mutation

69. Which of the following changes would be expected if a CAUUUG sequences of bases mutated to CACUUG? A. the amino acid sequence would be shorter than expected B. the identity of one amino acid would change C. the identity of more than one amino acid would change D. the amino acid sequence would remain unchanged

65. If a portion of a messenger RNA molecule contains the base sequence A-A-U, the corresponding transfer RNA base sequence is A. A-A-U B. G-G-T C. T-T-C D. U-U-A

70. An Okazaki fragment is a: A) fragment of DNA resulting from endonuclease action. B)fragment of RNA that is a subunit of the 30S ribosome. C) piece of DNA that is synthesized in the 3'5 ' direction. D) segment of DNA that is an intermediate in the synthesis of the lagging strand. E) segment of mRNA synthesized by RNA polymerase.

66. Which defines a codon? A. a protein that beins transcription by breaking apart H bonds B. a free-floating base that attaches to an open DNA strand C. the genetic code word of three bases on mRNA that specify one amino acid D. the strong bond between two complementary nitrogen bases

71. The compound that consists of ribose linked by an N-glycosidic bond to N-9 of adenine is: A) a deoxyribonucleoside. B) a purine nucleotide. C) a pyrimidine nucleotide. D) adenosine monophosphate. E) adenosine.

67. What is the role of tRNA during translation? A. bond to open the DNA strand to carry the code for protein synthesis out of the nucleus B. carry ribosomes to the site of protein synthesis C. break aparty mRNA and send it back to the nucleus so that it can be reused D. Carry amino acids to the mRNA for correct placement into the protein chain

72. Which one of the following is true of the pentoses found in nucleic acids? A) C-5 and C-1 of the pentose are joined to phosphate groups. B) C-5 of the pentose is joined to a nitrogenous base, and C1 to a phosphate group. C) The bond that joins nitrogenous bases to pentoses is an O-glycosidic bond. D) The pentoses are always in the -furanose forms. E) The straight-chain and ring forms undergo constant interconversion.

68. This diagram shows which cellular process?

73. The nucleic acid bases: A) absorb ultraviolet light maximally at 280 nm. B) are all about the same size. C) are relatively hydrophilic.

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Narayana Dental PG Coaching - Biochemistry Week-01 Test (14-09-2014 D) are roughly planar. E) can all stably base-pair with one another

A. a synthesis reaction. B. a hydrolysis reaction. C. a redox process. D. a polymerization reaction. E. an anabolic process.

74. Which of the following statements concerning the tautomeric forms of bases such as uracil is correct? A) The all-lactim form contains a ketone group. B) The lactam form contains an alcohol group. C) The lactam form predominates at neutral pH. D) They are geometric isomers. E) They are stereoisomers.

82. The transfer of electrons from glucose to oxygen during aerobic respiration takes place in a stepwise fashion through a number of intermediates rather than by direct transfer. This is because: A. it is chemically impossible to transfer electrons directly from glucose to oxygen. B. the chemical intermediates donate some of their electrons in order to increase the electron pool. C. the energy of the electrons can be used to make ADP. D. the energy of the electrons can be used to make ATP. E. the energy of the protons can be used to make ATP.

75. Which of the following statements concerning anabolic reactions is FALSE? A. They are generally endergonic. B. They usually require ATP. C. They are part of metabolism. D. They may produce polysaccharides from monosaccharides. E. They may split complex molecules into their components.

83. In aerobic respiration, the electrons associated with the hydrogen atoms in glucose are transferred to: A. carbon in a series of steps. B. oxygen in a series of steps. C. NADH in a series of steps. D. the mitochondrial membranes. E. hydrogen ions.

76. Aerobic respiration, anaerobic respiration, and fermentation: A. are endergonic pathways. B. release free energy. C. require oxygen. D. are also known as organismic respiration. E. are anabolic pathways.

84. If conditions are aerobic, pyruvate flows directly into the _______ where some of its atoms are converted next to _______. A. cytosol; oxaloacetate B. cytosol; ATP C. mitochondria; glucose-6-phosphate D. mitochondia; acetyl coenzyme A E. mitochondria; citrate

77.Cellular respiration is most accurately described as a(n) ______________ process. A. anabolic B. catabolic C. metabolic D. endergonic E. fermentative 78. Select the anaerobic pathway. A. aerobic respiration B. citric acid cycle C. electron transport chain D. fermentation E. chemiosmosis

85. Which process does not match the products? A. electron transport and chemiosmosis—ATP, H2O, NAD+, FAD B. citric acid cycle—CO2, NADH, FADH2, ATP C. formation of acetyl CoA—Acetyl CoA, CO2, NADH D. glycolysis—pyruvate, ATP, NADH E. All of these processes match the products.

79. The overall reaction for the aerobic respiration of glucose is summarized as: A. C6H12O6 + 6 O2 + 6 H2O → 6 CO2 + 12 H2O + Energy. B. C4H12O4 + 12 H2O + 6 CO2 → 6 O2 + ATP + Energy. C. C4H12O4 + 6 O2 + 6 H2O → 6 CO2 + ATP + Energy. D. C4H12O2 + 6 O2 + ATP → 6 CO2 + 12 H2O + Energy. E. C6H12O6 + 6 H2O → 6 CO2 + 12 H2 + Energy.

86. Which process does not match the starting materials? A. electron transport and chemiosmosis—NADH, FADH2, O2, ADP, Pi B. glycolysis—glucose, ATP, NAD+, ADP, Pi C. citric acid cycle—acetyl CoA, H2O, NAD+, FAD, ADP, Pi D. formation of acetyl CoA—citric acid, CO2, NADH E. All of these processes match the starting materials.

80. In aerobic respiration, glucose is completely: A. reduced to ATP. B. reduced to energy. C. oxidized to water. D. oxidized to carbon dioxide. E. oxidized and reduced simultaneously.

87. During chemiosmosis, ____________ are transferred from NADH and FADH2 to electron acceptor molecules, and the energy released is used to create a(n) ____________ gradient across the inner mitochondrial membrane. A. protons; electron

81. Aerobic respiration is classified as:

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Narayana Dental PG Coaching - Biochemistry Week-01 Test (14-09-2014 B. electrons; proton C. ATP molecules; ADP molecule D. ADP molecules; ATP molecule E. water molecules; oxygen

94. In chemiosmosis, ATP is produced as hydrogen ions (protons) pass through: A. the outer mitochondrial membrane. B. ATP synthase. C. ATP dehydrogenase. D. ATP decarboxylase. E. a series of electron carriers.

88. NADH and FADH2 are the products of: A. decarboxylation reactions. B. reduction reactions. C. glycolysis. D. formation of acetyl coenzyme A. E. chemiosmosis.

95. Select the processes that are matched with the incorrect amount of ATP produced by that process per glucose molecule. A. glycolysis—2 ATP (net) B. citric acid cycle—4 ATP C. electron transport chain—32 ATP D. alcohol fermentation—2 ATP E. lactate fermentation—2 ATP

89. Which of the following statements concerning decarboxylation reactions is FALSE? A. They occur as part of the citric acid cycle. B. They produce CO2 that is then exhaled via breathing. C. They involve the removal of a carboxyl group (-COOH) from a substrate. D. They are one type of general reaction that occurs during aerobic respiration. E. They involve the removal of two protons and two electrons.

96. In the skeletal muscle cells of vertebrates, as many as ____________ molecules of ATP areproduced from one molecule of glucose. This is less than might be expected, because electrons from NADH produced during glycolysis must be shuttled through the ____________ mitochondrial membrane at a cost. A. 2; outer B. 2; inner C. 38; inner D. 6; outer E. 36; inner

90. In glycolysis, fructose-1, 6-bisphosphate splits, forming two molecules of: A. ADP. B. citric acid. C. G3P. D. glucose. E. acetyl CoA.

97. Which of the following statements about the chemiosmotic theory is correct? A) Electron transfer in mitochondria is accompanied by an asymmetric release of protons on one side of the inner mitochondrial membrane. B)It predicts that oxidative phosphorylation can occur even in the absence of an intact inner mitochondrial membrane. C) The effect of uncoupling reagents is a consequence of their ability to carry electrons through membranes. D) The membrane ATP synthase has no significant role in the chemiosmotic theory. E) All of the above are correct

91. NADH is formed when NAD+ accepts: A. a proton. B. a hydrogen atom. C. a pair of protons and an electron. D. a proton and a pair of electrons. E. two hydrogen atoms. 92. Which of the following statements about the electron transport chain is true? A. Protons are pumped out of the mitochondria by the complexes of the electron transport chain. B. The proton gradient established during electron transport is a form of potential energy. C. The electron transport chain can be found in the mitochondria of aerobic bacteria and other cells. D. The movement of protons down a concentration gradient is an endergonic process. E. ATP synthesis associated with the electron transport chain is an example of substrate level phosphorylation.

98. Almost all of the oxygen (O2) one consumes in breathing is converted to: A) acetyl-CoA. B) carbon dioxide (CO2). C) carbon monoxide and then to carbon dioxide. D) none of the above. E) water

93. When hydrogen ions (protons) are pumped across the inner mitochondrial membrane, they form a proton gradient. ATP is then formed by a process known as: A. glycolysis. B. the citric acid cycle. C. chemiosmosis. D. pyruvate synthesis. E. substrate-level phosphorylation.

99. Oligomycin inhibits ATP synthase while DNP is an uncoupler. Therefore, DNP will: A) allow electron transfer in the presence of oligomycin. B) allow oxidative phosphorylation in the presence of oligomycin. C) block electron transfer in the presence of oligomycin. D) diminish O2 consumption in the presence of oligomycin E) do none of the above

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Narayana Dental PG Coaching - Biochemistry Week-01 Test (14-09-2014 100. Which of the following statements about energy conservation in the mitochondrion is false? A) Drug that inhibits the ATP synthase will also inhibit the flow of electrons down the chain of carriers. B) For oxidative phosphorylation to occur, it is essential to have a closed membranous structure with an inside and an outside. C) The yield of ATP per mole of oxidizable substrate depends on the substrate. D) Uncouplers (such as dinitrophenol) have exactly the same effect on electron transfer as inhibitors such as cyanide; both block further electron transfer to oxygen. E) Uncouplers ―short circuit‖ the proton gradient, thereby dissipating the proton motive force as heat

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