Exam 4 Spring 2022

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Kennesaw State University *

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3500

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Chemistry

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Dec 6, 2023

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Biochemistry CHEM 3500 Spring 2022 Exam 4 Name: ______________________________ Dr. Meades 35 possible points For questions 1-34, choose the one best answer (1 point each). Bold words are clues. 1.) Which lists the equivalent functional component or space in chloroplasts and mitochondria? A) chloroplastic outer memb. = mitochondrial outer memb. B) nuclear memb. = stroma C) thylakoid space = matrix D) chloroplastic outer memb. = mitochondrial inner memb. E) thylakoid memb. = cell memb. 2.) The molecule to the right is involved in what anabolic biochemical pathway? A) nucleotide synthesis B) glycogen synthesis C) fatty acid synthesis D) photosynthesis E) gluconeogenesis 3.) The next step of the pathway converts the molecule shown into _____. A) HMG-CoA B) acetyl-CoA C) malonyl-ACP D) 3-ketoacetyl-CoA E) crotonyl-ACP 4.) The enzyme in the reaction depicted below belongs to what class ? A) hydrolase B) isomerase C) lyase D) transferase E) ligase F) oxidoreductase 5.) The above enzyme is utilized for degrading which type of fatty acid? A) even-position unsaturated fatty acids B) odd-position unsaturated fatty acids C) polyunsaturated fatty acids D) odd-chain length fatty acids E) saturated fatty acids F) fatty acids with double bonds at position 14 6.) All five nitrogen atoms found in adenosine monophosphate originate from what sources in de novo synthesis? A) glycine, glutamine, arginine B) glutamate, glycine, aspartate C) glycine, alanine, aspartate D) N 10 -formyl-THF, glycine, CO 2 E) aspartate, glycine, glutamine F) glutamate, glycine, asparagine 7.) During conversion of UMP to CTP in pyrimidine synthesis, how many reactions consuming ATP occur? A) 0 B) 1 C) 2 D) 3 E) 4 F) cannot be determined 8.) During the mechanism of ribonucleotide reductase, where does a radical exist? A) 2 O of ribose ʹ B) 3 C of deoxyribose ʹ C) 3 O of deoxyribose ʹ D) a C of tyrosine E) all of the above 9.) The major metabolite regulating the activity of glycogen phosphorylase is _____ in liver cells, and _____ in muscle cells. A) fructose / ATP B) AMP / ATP C) ATP / glucose D) GTP / GMP E) insulin / Ca 2+ F) glucose / ATP G) insulin / glucagon 10.) Partial  oxidation of cis,cis -19:2Δ 5,8 yields which of the following in addition to a 7-carbon saturated acyl-CoA ? (Hint: NADH is not the same molecule as NADPH) A) 8 acetyl CoA + 7 FADH 2 + 8 NADH + 1 propionyl-CoA B) 8 acetyl CoA + 7 FADH 2 + 7 NADH - 1 NADPH C) 6 acetyl CoA + 5 FADH 2 + 5 NADH - 2 NADPH D) 6 acetyl CoA + 5 FADH 2 + 6 NADH - 1 NADPH E) 9 acetyl CoA + 8 FADH 2 + 7 NADH - 1 NADPH 11.) Complete  oxidation of cis -12:1Δ 7 - CoA , yields how many ATP equivalents? (Hint: NADPH or NADH worth 2.5 ATP, FADH 2 worth 1.5 ATP, and acetyl-CoA worth 10 ATP) A) < 77.5 B) 77.5 C) 78.5 D) 80 E) 82.5 F) 84 G) > 84 12.) Which ONE of the following monosaccharides would be removed as glucose during glycogen degradation ? 13.) Which ONE of the following monosaccharides could be acted upon by the branching enzyme at this point ? 14.) Which ONE of the following monosaccharides could have been added by glycogenin during glycogen synthesis ? 15.) Which ONE of the following monosaccharides would be moved by the debranching enzyme during glycogen degradation ? ( Answer choices may be used more than once. )

16.) Using the pentose phosphate pathway, the non-oxidative steps result in which of the following conversions? A) triose phosphate + heptose phosphate  hexose phosphate + tetrose phosphate B) tetrose phosphate + triose phosphate  hexose phosphate + pentose phosphate C) pentose phosphate + pentose phosphate  hexose phosphate + triose phosphate D) pentose phosphate + hexose phosphate  heptose phosphate + tetrose phosphate E) triose phosphate + triose phosphate  hexose phosphate + pentose phosphate 17.) The complete degradation of purine nucleotides results in which of the following pair of products? A) ribose & uric acid B) ribose-5-phosphate & uric acid C) ribose-1-phosphate & uric acid D) ribose & urea E) ribose-5-phosphate & urea F) ribose-1-phosphate & urea 18.) Which of the following is TRUE ? Binding of _____ in the specificity site of ribonucleotide reductase promotes _____. A) dATP / the binding of UTP or CTP at the active site B) dCTP / the formation of dADP or dGDP at the active site C) dGTP / the formation of dATP at the active site D) dTTP / the binding of GDP at the active site E) dUTP / the binding of GDP at the active site 19.) Nucleotide diphosphate kinase (NDPK) can use all except which of the following as a substrate? A) ADP B) ATP C) GMP D) GDP E) UDP 20.) S. cerevisiae ribonucleotide reductase (RNR) is a typical eukaryotic RNR that makes use of a tyrosine radical in the active site. Which of the following new drug rationales describes a potentially effective means to inhibit this enzyme? A) The drug inhibits RNR by forming the two cysteines into a disulfide. B) The drug inhibits RNR by permanently binding dATP in the activity site. C) The drug inhibits RNR by permanently crosslinking (covalently attaching) subunit R1 to R2. D) The drug inhibits RNR by preventing the binding of 5,10-methylenetetrahydrofolate (a methyl donor). E) The drug inhibits RNR by allowing only purines to bind in the activity site. 21.) In the synthesis of cholesterol, _____ acetyl-CoA molecules are consumed to make each squalene (C 30 ) molecule. A) 2 B) 3 C) 6 D) 12 E) 15 F) 18 G) 30 22.) Effectively, how many protons of the gradient across the thylakoid membrane are depleted when ATP synthase completes two full turns (720°) forming molecule(s) of ATP and relocating it(them) to the cytoplasm? A) 0 B) 3 C) 4 D) 9 E) 12 F) 18 G) 24 23.) ( Slide 4d#15 ) The PLP-dependent transamination reaction interconverts α-keto acids and α-amino acids. Substrates 3-hydroxy-α- ketobutyrate and glutamate would produce α-ketoglutarate and which of the following as products? A) glutamine B) serine C) threonine D) hydroxypyruvate E) aspartate F) oxaloacetate 24.) One of the major products of photosynthesis is _____. A) O 3 B) H 2 O C) NADP + D) CO 2 E) photon of light F) none of the above 25.) Concerning the regulation of glycogen metabolism, activation of protein kinase A would have the combined effects of _____ glycogen synthase while _____ glycogen. A) phosphorylating and activating / synthesizing B) phosphorylating and deactivating / synthesizing C) dephosphorylating and deactivating / degrading D) dephosphorylating and activating / degrading E) phosphorylating and deactivating / degrading F) phosphorylating and activating / degrading G) dephosphorylating and deactivating / synthesizing 26.) The lactam to the right is made from cyclization of what biomolecule? A) glutamine B) proline C) malonyl-CoA D) mevalonate E) HMG-CoA F) asparagine G) citrulline 27.) The leaving group X would be best described as _____. A) ammonia B) water C) CoA D) CO 2 E) bicarbonate F) β-keto acid G) urea 28.) The main function of blood borne VLDL proteins is to transport _____ from _____ to _____. A) cholesterol, liver, adipose cells B) cholesterol, adipose cells, liver C) cholesterol, liver, small intestine D) triacylglycerol, liver, adipose cells E) triacylglycerols, small intestine, liver 29.) During the mechanism of photosystem II, the calcium ion in the active site cluster changes oxidation state how many times? A) 0 B) 1 C) 2 D) 3 E) 4 F) 5 G) 6

Biochemistry CHEM 3500 Spring 2022 Exam 4 Name: ______________________________ 30.) During the cyclic flow of electrons through PS I, how many photons are needed per electron to complete the entire cycle? A) 0 B) 1 C) 2 D) 3 E) 6 F) cannot be determined 31.) Which of the following statements about β-oxidation of fatty acids is FALSE ? A) All fatty acids must be activated to acyl-CoAs before entering the pathway. B) Thiolytic cleavage releases acetyl-CoA and an acyl-CoA shortened by two carbon atoms in the final step of the cycle. C) Only the second dehydrogenation reaction produces a C=O double bond. D) Both dehydrogenation reactions use NAD+ as the electron acceptor. E) For an odd -length fatty acid containing a C=C double bond, the location of the C=C double bond remains odd. F) The second oxidation step is unfavorable because it produces an unstable β-keto arrangement. 32.) During starvation in humans, acetyl-CoA CANNOT be converted to _____, but CAN be converted to _____. A) fatty acids / cholesterol B) pyruvate / acetone C) oxaloacetate / RNA D) glucose / lactose E) all of the above 33.) Choose the correct path taken by protons during ATP synthesis in chloroplasts . A) stroma  cytochrome c  intermembrane space  ATP synthase  stroma B) intermembrane space  Complex II  matrix  ATP synthase  intermembrane space C) thylakoid space  Complex III  matrix  ATP synthase  thylakoid space D) stroma  thylakoid space  ATP synthase  stroma E) intermembrane space  ATP synthase  stroma 34.) The photosynthetic enzyme complex converts 2 H 2 O to O 2 using a cubane metal cluster as a cofactor. Why is this cofactor used? A) Manganese is able to exist stably at many oxidation states. B) Water binds tightly to calcium. C) Iron is able to exist stably at multiple oxidation states. D) The cubic arrangement absorbs photonic energy. E) Iron-sulfur clusters are very stable at pH 7. F) Chlorophyll molecules efficiently transfer energy to this cofactor. For question 35, a short answer is required for credit; no partial credit will be given. Excessive length in your reply will not help you. 35.) (1 point) The activation of fatty acids by acyl-CoA synthetase follows a two-step mechanism similar to activation of amino acids by aminoacyl-tRNA synthetase. One pair of analogous substrates is CoA and tRNA. List another pair of analogous substrates in the former and latter enzymes, respectively.

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