上交生化考研练习题刘建华出Test1

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1、14Chapter 1 Biochemistry: An Evolving Science这是上海交通大学生命科学学院生化刘建华老师出的本科生卷子，我因为找人弄到了，对生化题的改革有所准备，所以11年生化考的不错，起码是个三位数了，呵呵，如愿以偿地进入了上交生科院呵呵，还有很多，如果需要请QQ联系我，2519067730I Matching QuestionsUse the following to answer questions 1-10. Choose the correct answer from the list below. Not all of the answers will

2、be used.a) uridineb) truec) DGd) thyminee) DHf) sugar-phosphate unitsg) covalenth) Archaeai) entropyj) a systemk) 3l) 2m) falsen) positiveo) negativeDNA is made from the building blocks adenine, guanine, cytosine, and _. The DNA backbone is made from repeating _. _ The number of hydrogen bonds forme

3、d between A and T. _ The number of hydrogen bonds formed between G and C. The fundamental groups of organisms include Eukarya, Bacteria, and _.The strongest bonds in molecules are _.It is that hydrogen bonds are usually stronger than covalent bonds.All matter within a defined region of space is reco

4、gnized as .The DG of a spontaneous reaction in specified conditions must be . is Gibbs free energy.II Multiple Choice11. The structure of DNA described by Watson and Crick included A) a double helix. B) the sugar phosphate backbone aligned in the center of the helix. C) the base pairs that are stack

5、ed on the inside of the double helix. D) a and b. E) a and c. 12.What did Watson and Crick suggest to be significant about the base pairing found in the helix? A)It allowed the DNA to twist in a helix. B)The DNA could be circular. C)It was a mechanism for copying. D)All of the above.E)None of the ab

6、ove. 13.Approximately what percentage of the human genome encodes for proteins? A)50%B)90%C)10%D)3%E)None of the above.14.What gives proteins such a dominant role in biochemistry? A)the variation in protein sizes B)the ability to act as a blueprint C)their ability to self-replicate D)their ability t

7、o spontaneously fold into complex three-dimensional structures E)All of the above. 15.If the whole chain is used in a non-overlapping frame, how many amino acids are defined by this DNA sequence: ATGTTTGGACTA? A) four B) two C) twelve D) six E) three 16.What is the H+ concentration in a urine sample

8、 that has a pH of 6? A)10-6 MB)10-8 MC)106 MD)10-14 ME)8 M17.Which of the following is considered as a noncovalent bond?A)electrostatic interactions D)All of the above. B)hydrogen bonds E)None of the above. C)van der Waals interactions 18.The energies for hydrogen bonds are approximately A)400 kJ/mo

9、l. D)200 kJ/mol. B)100240 kJ/mol. E)None of the above. C)420 kJ/mol. 19.What pairs of atoms in bases are involved in hydrogen bonds? A)NH and OH D)All of the above. B)NH and SH E)None of the above. C)OH and PO 20.Typical van der Waals energies are about A)420 kJ/mol. D)All of the above. B)24 kJ/mol.

10、 E)None of the above. C)200 kJ/mol. 21.What two properties of water are important for biological interactions? A)the polarity of water D)a and c B)the density of water E)b and c C)the cohesive properties of water 22.The First Law of Thermodynamics states A)diversity is the result of gradual evolutio

11、n. B)the total entropy of a system and its surroundings always increases for a spontaneous process. C)the total energy of a system and its surroundings is constant. D)light is both particle and wave. E)None of the above. 23.The Second Law of Thermodynamics states A)the total entropy of a system and

12、its surroundings always increases for a spontaneous process. B)temperatures will always decrease. C)the total energy of a system and its surroundings is constant. D)diversity is the result of gradual evolution. E)None of the above. 24.List atoms commonly found in biological molecules that are often

13、hydrogen-bond acceptors. A) carbon B) oxygen C) nitrogen D) b and c E) All of the above. 25.Enthalpy is defined as A)a spontaneous reaction. D)All of the above. B)the entropy of the system. E)None of the above. C)the heat content of a system. 26.If a particular reaction has a negative DG, is it like

14、ly to occur? A)Not unless energy is added to the system. B)Yes, if it is coupled to another reaction. C)Yes, it is spontaneous. D)No, it will never occur. E)Yes, if it takes place within a constrained area. 27.What happens to nonpolar molecules in water? A)They dissolve independently. D)All of the a

15、bove. B)They aggregate together. E)None of the above. C)They precipitate. 28.What is the A-/HA ratio when the weak acid is in a solution one pH unit above its pKa?A)1 : 1D)2 : 1B)1 : 10E)None of the above.C)10 : 129.Why does DNA denature when the pH is raised above 9?A)Protons dissociate from guanin

16、e bases disrupting the hydrogen bonding to the other strand.B)Protons bind to guanine residues giving them additional positive charges which disrupt the hydrogen bonding to the other strand.C)Protons bind to functional groups that serve as hydrogen-bond acceptors, thus disrupting the hydrgogen bondi

17、ng to the other strand.D)Protons dissociate from the phosphate groups in the backbone, which disrupts the hydrogen-bonding pattern between strands.E)None of the above.30.Stereochemistry can be easily depicted in a simple form using A)Ball-and-stick models. D)Fisher projections. B)ribbon diagrams. E)

18、None of the above. C)Space-filling models. 31.Which of the following is the Henderson-Hasselbach equation?A)D)B)E)None of the above.C)32.What are the primary chemical components present in a phosphate buffer at pH 7.4?A)H3PO4 and PO4-3D)H2PO4- and HPO4-2B)H2PO4- and PO4-3E)H3PO4 and HPO4-2C)HPO4-2 a

19、nd PO4-3Short-Answer Questions33. What are some of the medical implications of the human genome project? 34. What is the significance of hydrogen bonding in biochemical structures such as DNA? 35. What adaptation affected evolutionary diversity? 36. Describe resonance structures. 37. What is an elec

20、trostatic interaction? Give an example. 38. How is water able to be a solvent for so many biological molecules? 39. What is the net effect of many van der Waals interactions? 40. If most proteins are found surrounded by water in the cell, what type of functional groups would you expect to find on th

21、e surface of a water soluble protein? 41. How are electrostatic forces used in protein folding? 42. If the First Law of Thermodynamics is true, how can biological processes be carried out? 43. How can a cell exist if the Second Law of Thermodynamics is true? 44. Provide a simple example of entropy p

22、rocesses. 45. What does this equation mean:DG = DH system TDS system 0? 46. What is the significance of using DG in biochemistry? 47. What thermodynamic and free-energy changes participate in protein folding? 48. How do hydrophobic interactions aid in protein folding? 49. What are the enthalpy and e

23、ntropy changes that accompany the formation of DNA double helixes from complementary single strands of DNA?50. Describe the shape of methane. Matching QuestionsUse the following to answer questions 1-10:Choose the correct answer from the list below. Not all of the answers will be used.a) l-amino aci

24、dsb) waterc) protonsd) Zwitterionse) secondary structuref) tertiary structureg) Ramachandranh) cysteinei) extracellularj) histidinek) prolinel) Sangerm) d-amino acids _ are the chiral type of amino acids found in proteins. _ are another name for dipolar molecules. Disulfide bonds are formed by pairs

25、 of _? _ is the amino acid with a pKa near neutral pH. When a peptide bond is formed, _ is also made? Proteins with extensive disulfide links likely to be found _? _ disrupts the helix because its side chain contains a unique ring structure that restricts bond rotations. _ plot allows one to investi

26、gate the likely orientation of certain amino acid pairs. Alpha helices, sheets, and turns are referred to as _ of proteins. The overall structure of a protein is referred to as _.Fill in the Blank Questions The amino acid that contains a weakly acidic “phenolic” group is _. _ is a fibrous protein an

27、d is the primary component of wool and hair. Every third residue in the protein collagen is _. Disulfide bonds in proteins can be reduced to free sulfhydryl groups by reagents such as _. A protein is considered to be _ when it is converted into a randomly coiled structure without its normal activity

28、. _ is the major fibrous protein present in skin, bone, tendon, cartilage, and teeth. Collagen contains _, a modified amino acid. Agents such as _ and guanidine hydrochloride denature proteins by disrupting the noncovalent interactions. _ refers to the spatial arrangement of subunits and the nature

29、of their interactions The _ -sheet structure occurs when the two strands are oriented in opposite directions (N C).Multiple Choice Questions What determines a proteins function? A) structure B) gene sequence C) N-terminal amino acids D) None of the above.E) All of the above. Key properties of protei

30、ns include A) a wide range of functional groups. B) an ability to possess either rigid or flexible structures as dictated by functional requirements. C) the ability to interact with other proteins. D) a and b. E) All of the above. What charged group(s) are present in glycine at a pH of 7? A) NH3+ B)

31、 COO- C) NH2+ D) a and b E) a, b, and c At a pH of 12, what charged group(s) are present in glycine? A) -NH3+ B) -COO- C) -NH2+ D) a and b E) a, b, and c In what pH range is zwitterionic Alanine the predominate structure?A) 02 B) 914 C) 810 D) 24 E) 29 Which amino acids contain reactive aliphatic hy

32、droxyl groups? A) serine and methionine B) serine and threonine C) methionine and threonineD) cysteine and methionine E) cysteine and threonine Positively charged amino acids at a neutral pH are_. A) lys, arg, and his B) his, arg, and cys C) cys, arg, and metD) lys, arg, and pro E) arg, glu, and his

33、 _ is the N-terminus of the peptide Phe-Ala-Gly-Arg.A) Ala B) Phe C) Phe and Arg D) Arg E) None of the above. What is the approximate mass of a protein containing 200 amino acids? (Assume there are no other protein modifications.) A) 20,000 B) 11,000 C) 22,000 D) 222,000 E) None of the above. _ won

34、a Nobel Prize for his landmark work in sequencing the protein insulin. A) Pauling B) McClintock C) Gilbert D) Maxam E) Sanger Why is the peptide bond planar? A) Bulky side chains prevent free rotation around the bond. B) It contains partial double-bond character, preventing rotation. C) Hydrogen bon

35、ding between the NH and C=O groups limits movement. D) None of the above. E) All of the above. The configuration of most -carbon atoms of amino acids linked in a peptide bond is A) cis. B) circular. C) parallel. D) trans. E) perpendicular. What structure(s) did Pauling and Corey predict in 1951? A)

36、helix B) sheet C) turns D) a, b, and c E) a and b Which of the following protein(s) contain examples of helical character? A) keratin B) ferritin C) myosin D) tropomyosin E) All of the above. Where are and turns and loops often found? A) in a hydrophobic pocket B) on the interior cleftC) at the prot

37、ein interface with ligand D) on the surface of proteins E) None of the above. What are some of the modifications that proteins acquire? A) cleavage and trimming of the protein B) addition of carbohydrate groupsC) phosphorylation of certain groupsD) a, b, and c E) b and c Which of the following amino

38、 acid residues would most likely be buried in the interior of a water soluble, globular protein? A) Asp B) Ser C) Phe D) Lys E) GlnShort-Answer Questions How does a proteins amino acid sequence influence the tertiary structure? What is the advantage of having 20 different amino acids available to fo

39、rm proteins? What is the advantage of protein interaction and assembly with other proteins? What are the three aromatic amino acids? Which amino acid side chains are capable of ionization? How does the protein backbone add to structural stability? Why are all the theoretical combinations of phi and

40、psi not possible? Describe some of the features of an helix. What is the “hydrophobic effect” as it relates to protein structure? What is a protein domain? What are prions? In the ribonuclease experiments performed by Anfinson, what was the significance of the presence of the reducing agent mercapto

41、ethanol? What is the advantage of having certain regions of partially correct folded regions? Matching QuestionsUse the following to answer questions 1-10:Choose the correct answer from the list below. Not all of the answers will be used.a) HPLCb) specific activityc) MALDI-TOF mass spectrumd) zonal

42、centrifugatione) nascentf) SDSg) epitopeh) Svedbergi) immunoglobulinj) centrifugationk) overlap peptidesl) affinity chromatography The ratio of enzyme activity relative to total protein is called _. The first step in protein purification from a homogenate is usually _. _ is a type of purification ba

43、sed on the attraction of the protein for a particular chemical group. _ should be added prior to gel electrophoresis to denature the proteins. Sedimentation coefficients are described as _ units. Proteins with different sedimentation coefficients can be separated by _. In order to sequence a whole p

44、rotein, _ are used. _ proteins are used to describe the original, uncleaved protein. _ is another name for an antibody. _ is another name for an antigenic determinant. Fill in the Blank Questions Proteins can be separated from small molecules and ions through a semi-permeable membrane by _. Exclusio

45、n gel or gel-filtration chromatography separates molecules on the basis of _. _ is a chemical reagent that is often used to detect the presence of amino acids. In the Edman procedure for peptide sequence, phenyl isothiocyanate is used to selectively remove the _ residue as a PTH-derivative. Disulfid

46、e bonds in peptides and proteins are readily oxidized to cysteic acid residues by treatment with _. MALDI-TOF is the abbreviation for _. Automated peptide synthesis involves the activation of the carboxyl group of the incoming amino acid by _ and then reaction with the amino group of the growing pep

47、tide chain. Polypeptides can be fragmented into smaller peptides by cleavage with chymotrypsin, which hydrolyzes the peptide bond at the C-terminal side of _ residues. _ gels are often used as the media for electrophoretic techniques such as SDS-PAGE and isoelectric focusing. The mobility of protein

48、s in SDS-PAGE is inversely proportional to the _.Multiple Choice Questions When enzymes are purified, the assay is often based on A) light absorbance. B) temperature changes. C) catalytic activity. D) mRNA levels. E) pH. Proteins that are not catalysts are often assayed using A) antibody binding ass

49、ays. B) None of the above. C) catalytic activity. D) All of the above. E) amino acid analysis. What is the advantage of adding SDS to gel electrophoresis? A) SDS colors the proteins for visualization. B) SDS reduces disulfide bonds. C) SDS allows proteins to be separated on the basis of approximate

50、mass. D) None of the above. E) All of the above. Two-dimensional electrophoresis is a combination of what two techniques? A) isoelectric focusing and affinity chromatography B) ion-exchange chromatography and SDS-PAGE C) affinity chromatography and SDS-PAGE D) isoelectric focusing and SDS-PAGE E) is

51、oelectric focusing and ion-exchange chromatography Which of the following affect the sedimentation of a particle? A) mass B) shape C) the density of the solution D) All of the above.E) a and b Cyanogen bromide cleaves the peptide bond at A) the carboxyl side of Arg and Lys residues. B) the carboxyl

52、side of Met residues. C) the amino terminus. D) None of the above. E) All of the above. Trypsin cleaves the peptide bond at A) the carboxyl side of Arg and Lys residues. B) the carboxyl side of Met residues. C) the amino terminus. D) None of the above. E) All of the above. Which of the following tec

53、hniques can be used to determine the site of a disulfide bond? A) Edman degradation B) MALDI-TOF C) affinity chromatography D) SDS-PAGE E) diagonal electrophoresis What types of molecules can serve as antigens? A) proteins B) polysaccharides C) metal ions D) All of the above.E) a and b An ELISA can

54、be used for A) quantitative analysis. B) size analysis. C) absorbance measurements. D) All of the above.E) None of the above. A technique used to identify proteins after gel electrophoresis, which employs antibodies in the detection process. A) Southern Blot B) Southwestern Blot C) Northern Blot D)

55、Western Blot E) None of these. A technique that can be used to study protein location in cells. A) NMR spectroscopy B) Western blotting C) fluorescent microscopy D) ion-exchange chromatography E) X-ray crystallography The use of synthetic peptides includes A) use as antigens for making antibodies. B

56、) drugs. C) “hooks” used in purification. D) All of the above. E) a and c. Which technique cannot be used for quantitative analysis? A) X-ray crystallography B) ELISAC) absorbance spectroscopy D) All of the above.E) None of the above. Techniques that can be used to obtain information about protein s

57、hape are A) X-ray crystallography. B) NMR spectroscopy. C) SDS-PAGE. D) a and b. E) a, b, and c. Short-Answer Questions Why is an assay necessary for protein purification studies? How is lactic acid dehydrogenase assayed? How do gel-filtration and ion-exchange chromatography differ? How can a protei

58、ns isoelectric point be used in protein purification? What is the purpose of determining the specific activity, yield, and purification level of a protein purification protocol? What type of information can be obtained from ultracentrifugation? What is peptide-mass fingerprinting? Describe the Edman degradation method for protein-sequence analysis. How can the amino acid sequences be used to design a