课程名称︰生物化学 课程性质︰化学系五选三必修 课程教师︰陈平 开课学院：理学院 开课系所︰化学系 考试日期（年月日）︰2012/03/21 考试时限（分钟）：90mins 是否需发放奖励金：是 （如未明确表示，则不予发放） 试题 : Exam2 223 U0860 3/21/2012 (TotaL 112 pts, maximum 105 pts) Name(1pt):_____________ 学号(1pt):_____________ I. Multiple Choice (2x26 pts; There is only one correct answer) ___ 1. What are some of the protein modifications? A) cleavage and trimming of the protein B) addition of carbohydrate groups C) phosphorylation of certain groups D) B and C E)A, B and C ___2 The term “proteome” has been used to describe: A) the tertiary structure of a protein. B) the structure of a protein-synthesizing ribosome. C) the complement of proteins encoded by an organism's DNA D) regularities in protein structures. E) regions (domains) within proteins. ___3. For the study of a protein in detail, an effort is usually made to first; A) conjugate the protein to a known molecule. B) determine its amino acid composition. C) determine its molecular weight. D) determine its amino acid sequence. E) purify the protein. ___4. Which separation technique(s) is based on size/mass? A) dialysis B) size exclusion chromatography. C) SDS-PAGE. D) B and C. E) A, B, and C. ___5. Which separation technique(s) would you most likely use for purifying Arg-rich protein? A) size exclusion chromatography. B) cation exchange chromatography. C) anion exchange chromatography. D) dialysis. E) none of the above. ___6. What is the advantage of adding SDS to gel e1ectrophores? A) SDS colors the proteins for visualization. B) SDS reduces disulfide bonds. C) SDS allows proteins to be separated on the basis of approximate mass. D) None of the above. F) All of the above. ___7. In a mixture of the five proteins listed below, which should elute second in size-exclusion (gel filtration) chromatography? A) cytochromc c, Mr=13,000 B) imrnunoglobulin G, Mr=145,000 C) ribonuclease A, Mr=13,700 D) RNA polynierase, Mr=450,000 E) serum albumin, Mr=68,500 ____8. At the isoelectric pH of a tetrapeptide.: A) the amino and carboxyl termini are not charged. B) two internal amino acids of the tetrapeptide cannot have ionizable R groups. C) the total net charge is zero. D) there are four ionic charges. E) only the amino and carboxyl termini contribute charge. ____9. Two-dimensiornil electrophoresis is a combination of what two techniques? A) isoelectric focusing and affinity chromatography B) ion-exchange chromatography and SDS-PAGP C) affinity chromatography and SDS-PAGE D) isoelectric focusing and SDS-PAGE E) isoelectric focusing and ion-exchange chromatography ____10. Which of the following affect the sedimentation velocity of a partcle? A) mass B) shape C) the density of the solution D) A and C E) all of the above ___11. What types of molecules can serve as antigens? A) proteins B) polysaceharides C) metal ions D) A and B E) A, B, and C ___12. A monoclonal antibody differs from a polyclonal antibody in that monoclonal antibodies: A) are produced by cells from the same organism that produced the antigen. B) have only a single polypepticle chain that can recognize an antigen. C) are synthesized by a population of identical, or “cloned,’ cells. D) are labeled with chemicals that can be visualized. E) are synthesized only in living organisms. ____13. A technique used to identify proteins after gel electrophoresis, which employs antibodies in the detection process. A) Western Blot B) Southwestern Blot C) Northern Blot D) Southern Blot E) none of the above ____14. Regarding ELISA: A) indirect ELISA uses two antibodies that bind the same epitope B) sandwich ELISA uses two antibodies that bind different epitopes C) the antigen (or sample) is coated on the wells for indirect ELISA D) B and C E) A,B, andC ___15. Regarding solid phase peptide synthesis A) excess reagents may be used to drive the reactions to completion B) no purification is necessary for the intermediates C) protecting groups for the backbone amine and the side chains are the same D) A and B E) A, B, and C ___16. Regarding circular dichroism spectroscopy: A) measures the difference between left and right circularly polarized light B) probes the π and π* electronic transitions of the amide bond C) the spectrum is a collective measurement of the tertiary structure of the w hole molecule D) A and B E) B and C ___17. Technique(s) that can be used to obtain atomic resolution protein structures including hydrogen positions is (are) A) X-ray crystallography B) NMR spectroscopy C) fluorescent microscopy D) A and B E) A,B and C ___18. The difference between a ribonucleotide and a deoxyribonucleotide is: A) ribo- is a pyranose, deoxy- is a furanose. B) deoxy- has an —H instead of an —OH at C-2’. C) ribo- has an extra —OH at C-4’. D) ribo- has the β configuration at C-1'; deoxy- has α configuration. E) none of the above. ___19. A major component of RNA but not of DNA is: Al adenine. B) guanine. C) cytosine. D) uracil. E) thymine. ___20. In B-DNA each deoxyribose is in the C-2’endo conformation. This means which of the following A) the furanose ring is completely planar B) the 2’ carbon is in the same plane as the 5’ carbon C) the 2’ carbon is in the same plane as the furanose ring oxygen D) the 2’ carbon is on the same side of the furanose ring as the 5’ carbon E) the 2’ carbon is on opposite side of the fqranose ring from the 5’ carbon ___21. In nucleotides and nucleic acids, syn and anti conformations relate to: A) sugar stereoisorners. B) base stereoisomers. C) sugar pucker D) rotation around the phosphodiester bond. E) rotation around the sugar-base bond. ___22. For the oligoribonucleotide pACGUAC: A) the nucleotide at the 5 end is a pyrimidine. B) the nucleotide at the 3’ end has a phosphate on its 3’ hydroxyl. C) the nucleotide at the 5’ end has a phosphate on its 5’ hydroxyl. D) All of the above are true. E) None of the above is true. ___23. Which of the following deoxyoligonucleotides will hybridize with a DNA containing the sequence AGACTGGTC? A) TCTGACCAG B) GAGTCAACT C) CTCATTGAG D) GACCAGTCT E) TCTGGATCT ___24 In double-stranded DNA: A) the ends of both strands are at one end of the helix. and both 3' ends are at the other end of the heilx B) sequence rich in A-T pairs are denatures less readily than those rich in G-C pairs C) the stucture is compatible only with right-handed (never a left-handed) heilx. D) the two strands have complementary sequences E) the sequence of bases has no effect on the overall stucture ___25. Based on Chatgaff's rules. vhich of the following is true: A) A=G B) A=C C) A=U D) A+T=G+C E) A+G=T+C ___26. Triple-helical DNA structures can resuit from Hoogsteen (non Watson-Crick) interactions. These interactions are primarily: A) hydrogcn bonds involving the bases. B) hydrogen bonds involving deoxyribose. C) covalant bonds involving the bases. D) covalent bonds involving deoxyribose. E) hydrophobic interactions involving the bases. II.Fill in the blanks (5*2 pts; 10 pts total) 1.What characteristics of proteins are uses for protein purification? 1)___________________ 2)___________________ 3)___________________ 4)___________________ 2.Which cation is frequently observed in G-quardruplexes? III. Please circle the antigen binding region of the antibody in the structure below? (2pts) IV. Reaction products. (12 points) , 1. Please draw (including stereochemistry) the product for the reaction between one alanine ane two ninhydrin molecules (aldehyde 3 points, colored ninhydnn adduct 3 points;total 6 points) 2. Please draw the products for the reaction between cyanogen bromide and Ac-Met-His-NH2(2*3 pts) V. Draw the mechanism for coupling between Fmoc-Leu-OH and H-Trp-NH2: mediated by HBTU in the presence of DIEA (Fmoc-Leu-OH. 3 pts H-Trp-NH2 3 pts; HBTU, 3 pts,initial urea adduct, 3 pts activated ester,3 pts final diptide 3 pts; total 18 pts) VI. Draw the chemicaI structures, including stereochemistry, the four different nucleotides that constitute DNA. Also, please circle the hydrogen bond donors and acceptors forWatson-Crick base pairing (4x3 structure, 4x1 Watson-Crick: total 16 pts) ans: I. ECEEB CBCDE DCADD DBBDD ECDDE A II. 1. 1.affinity 2.size 3.solubility 4.charge 2. K+ IV 1. - Ｏ Ｏ ∥ ︱ Ｏ ／＼／﹨ //╲╱╲ ∥ ︱○︱ =N- ︱○︱ ／＼ ＼／＼∕ \／＼／ H ∥ ∥ Ｏ Ｏ 2. 　 Ｏ Ｏ /`~O + ∥ ∥ ︱ / H3N＼／＼NH2 ／＼N▲￣∥ : H Ｏ ＼//＼ \ N HN—// --

※ 发信站: 批踢踢实业坊(ptt.cc) ◆ From: 140.112.250.20 ※ 编辑: a3225737 来自: 140.112.250.20 (03/28 21:19)