2004 – 2005学年第一学期 期末考试试卷（A 卷） 课程名称 生物化学（双语）课程编号 84310013 任课教师 熊丽 题型 选择 名词解释 简答题计算题论述题 总分 分值 30 24 16 10 20 100 得分 得分 评阅人 一、Part I Multiple choice (1’ ×30=30’) 1 Identify this functional group: A ketone B alcohol C aldehyde D carboxylic acid E ether F ester 2 Mitochondria and chloroplasts share a number of features in common. Which of the following is NOT one of them? A Both are found in all eukaryotic cells. B Both are surrounded by a double membrane. C Both contain DNA. D Both may have been derived from symbiotic bacteria that invaded primitive eukaryotic cells. E Both are important sites of energy conversion. 3 Which of the following molecules is not polar? A CO 2 B H 2O C NH 3 D CH 3OH 4 Which of the following amino acids strongly absorbs UV light? A Phe B Tyr C Trp D all of the above 5 Which of the following amino acids is likely to be found on the surface of a globular protein? A leucine B alanine C serine D valine
6 Free rotation about the peptide bond in a protein is restricted primarily because of
A partial double-bond character of the peptide bond.
B hydrogen bonding to the amide backbone groups.
C partial double-bond character of the N-Calpha bond.
D restrictions caused by local folding patterns.
E steric interference of neighboring amino acid side chains 院（
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A the proximal histidine (His93) and heme-Fe(II)
B His and Phe43
C His93 and His
D Phe43 and heme-Fe(II)
E Phe43 and V al68
8 Which of the following amino acids is least likely to be found in an extended alpha-helix?
A proline
B V aline
C arginine
D serine
9 Which of the following peptides is likely to form an amphipathic helix?
A phe-asp-arg-gly-leu-glu-ile-ile-lys-ser-gly
B phe-gly-leu-ile-asp-arg-glu-lys-ile-ser-gly
C arg-asp-ser-gly-phe-leu-ile-ile-gly-glu-lys
D phe-leu-ile-ile-gly-asp-arg-glu-lys-ser-gly
E phe-asp-gly-arg-leu-glu-ile-lys-ile-ser-gly
10 Which of the following statements about multisubunit globular proteins is incorrect?
A Multisubunit enzymes often assemble the active site with residues from adjacent subunits.
B Oligomers are more stable than subunit monomers.
C Errors during protein synthesis are minimized by the synthesis of shorter proteins.
D Subunits are typically held together by covalent interactions.
E Multisubunit proteins are typically regulated by ligand-induced changes in monomer subunit structure.
11 The role of molecular chaperones in protein folding is to:
A increase the rate of folding into the correct conformation by binding to newly synthesized, unfolded proteins.
B modifiy side chain residues in newly synthesized proteins in order to prevent interactions that could lead to
misfolding
C recognize, bind, and unfold incorrectly folded proteins, thus allowing them to refold properly.
D reduce incorrectly formed disulfide bridges that can lead to misfolding.
E target misfolded proteins for recycling by proteases.
12 Which of the following is defined as the "turnover number for an enzyme?"
A k1
B (k-1 + kcat)/k1
C kcat/Km
D k1/k-1
E kcat k-1
13 Y ou have obtained the following data for enzyme activity measured in the presence of an inhibitor, I. Identify the type of inhibition.
A competitive
B uncompetitive
C noncompetitive
D Cannot be determined
E None of the above.
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14 Phosphorylation is a common means of regulating protein activity. Which of the following amino acids are typically phosphorylated in proteins regulated by kinases? A tyrosine B serine C threonine D All of the above. E None of the above. 15 Enzymes accelerate reaction rates by: A altering the equilibrium of a reaction. B increasing the temperature of a solution. C increasing entropy. D decreasing the energy of the transition state. E lowering the energy of the products 16 Select the coenzyme that does not participate in hydride transfer reactions. A FMN B NADPH C FADH2 D NADH E A TP 17 The following reactions occur in glycolysis (Chapter 11) or the citric acid cycle (Chapter 12) and are known to either produce or consume reducing potential in the form of NADH. Based on the standard reduction potentials of the compounds involved, which reaction(s) would you expect to consume reducing potentials? (i) acetaldehyde --> ethanol (ii) pyruvate --> lactate (iii) pyruvate --> acetyl CoA A i B ii C i and ii D ii and iii 18 Y east can grow anaerobically and produce ethanol from glucose. What pathway do they likely use for this conversion? A glycolysis B citric acid cycle C oxidative phosphorylation D Since this is a biosynthetic process, they utilize an anabolic pathway. 19 Which of the following enzymes catalyzes a substrate-level phosphorylation reaction? A hexokinase B pyruvate kinase C glyceraldehyde-3-phosphate dehydrogenase D phosphoglycerate kinase E B and D 20 When glucose is needed by the body, what organ or tissue supplies it? A adipose tissue B liver C brain D intestine 21 In order for a radioactive CO2 to be released during anaerobic glycolysis that leads to ethanol formation, the label needs to be located at the ____ position of glucose. A 1 B 2 C 3 D 6 E A and D 22 Fatty acids A can be made from citric-acid cycle intermediates. B can be used to replenish citric-acid cycle intermediates. C can both be made from and replenish citric-acid cycle intermediates. D Neither are made from nor replenish citric-acid cycle intermediates 23 Hans Krebs was once asked what the purpose of the cycle he discovered was. He most likely replied that it was
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B the production of water.
C the production of reduced carbon compounds.
D the production of intermediates for biosynthesis
24 How many molecules of A TP are required for the complete metabolism of one molecule of glucose to CO2 in the pentose phosphate pathway?
A 1
B 2
C 3
D 4
E 5
F 6
25 Which of the following nucleotides does not undergo a ring deamination during catabolism?
A GMP
B AMP
C CMP
D UMP
26 How many carbons are donated by folate cofactors in a DNA molecule?
A 2 for every purine
B 2 for guanosine, 1 for adenosine, 1 for thymidine
C 1 for every purine, 1 for thymidine
D 2 for every purine, 1 for thymidine
27 Double-stranded nucleic acid helices:
A do not have a handedness.
B can be either right- or left-handed.
C are always left-handed.
D are always right-handed.
28 Y ou are carrying out a restriction digest on a DNA sample. One indication that the DNA is circular is:
A No matter which enzyme you use, the fragments all add up to the same overall length.
B Y ou cut with an enzyme that cuts the DNA twice, and you get two fragments.
C Y ou cut with an enzyme that cuts the DNA twice, and you get three fragments.
D When you cut the DNA with different enzymes, the fragments add up to different overall lengths.
29 Which of the following statements about DNA replication in prokaryotes is false?
A DNA synthesis proceeds along both strands at the same time.
B DNA synthesis proceeds in both directions from an origin simultaneously.
C Leading strand synthesis occurs in short bursts, creating a series of fragments.
D A polymerase complex can be found at the replication fork
30 Y ou are studying the role of Okazaki fragments in DNA replication. Y ou label replicating DNA with alpha-32P A TP. Once replication has completed, the label is found in:
A short RNA tracts.
B large DNA tracts.
C single phosphodiester bonds between a ribose and a deoxyribose.
D single phosphodiester bonds between two deoxyriboses.
E The label is not found in DNA.
得分评阅人Part II Define the following terms: ( 4’ ×6 = 24’)
1 pI
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2 DDRP
3 Tm
4 Anticodon
5 DNA libraries:
6 Essential amino acid: 得分 评阅人 Part III Briefly answer the following questions (8’ ×2= 16’ ) 1 If pyruvate was labeled on its methyl group, where would the label end up following one turn of the TCA cycle?
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2 The following is a cartoon that shows what happens in the trp operon in the presence and absence of tryptophan. Explain what is happening in this cartoon. 得分 评阅人 Part IV Calculation (10’ ×1= 10’ ) 1 Calculate how much A TP can be produced if Alanine is oxidized aerobically. 得分 评阅人 Part V Discuss the following question (20’ ×1= 20’ ) 1 During starvation, most tissues turn to using fatty acids for fuel after glycogen stores have become exhausted. However, some tissues, such as red blood cells, can only use glucose. Describe the process by which red cells obtain glucose during starvation conditions下载本文
