1. The B-dna structure found in solution is a a right-handed double helix of antiparallel chains (11 bp/turn) B left-handed double helix of antiparallel chains (10 bp/turn) C right-handed double helix of antiparallel chains(10 bp/turn). D left-handed zig-zag helix of antiparallel chains(12 bp/turn) E right-handed double helix of parallel chains(10 bp/turn) 2. dna differs from rna in the following features a DNA is resistant to base catalyzed hydrolysis; Rna is hydrolyzed by oh b dNA residues are linked by 3 -->5 phospho lester bonds RNA is 2 -->5 linked c DNA has deoxyribose residues; RNA has ribose residues D DNA contains the a.c. g and t bases Rna contains a c.g. and u e All but the second choice are correct d ifferences 3. Because DNa is a highly charged polyanion, its stability to heat denaturation ("melting") a does not depend on hydrophobic interactions B c decreases with increasing [salt d is independent ofG +C content E increases with increasing pH 4. The total contour length of dna in a human cell is about b 1 mm C10 d 1 meter E 12 furlongs 5. Polyacrylamide and agarose gel electrophoresis separate nucleic acids based primarily on their a length B ratio of mass/charge C (G+C)(A+T)content. D organismal origi E content of N (buoyant density) 6. The number of supercoils in a covalently-closed, circular DNA can only be a at least one of the phospho ester chains is cleaved b both of the phosphodiester chains are cleaved c histones are bound to the dna d the salt concentration is increased >10 M
1. The B-DNA structure found in solution is a A right-handed double helix of antiparallel chains (11 bp/turn). B left-handed double helix of antiparallel chains (~10 bp/turn). C right-handed double helix of antiparallel chains (~10 bp/turn). D left-handed zig-zag helix of antiparallel chains (12 bp/turn). E right-handed double helix of parallel chains (~10 bp/turn). 2. DNA differs from RNA in the following features A DNA is resistant to base catalyzed hydrolysis; RNA is hydrolyzed by OH- . B DNA residues are linked by 3'-->5' phosphodiester bonds; RNA is 2'-->5' linked. C DNA has deoxyribose residues; RNA has ribose residues. D DNA contains the A, C, G and T bases; RNA contains A, C, G, and U. E All but the second choice are correct differences. 3. Because DNA is a highly charged polyanion, its stability to heat denaturation ("melting"): A does not depend on hydrophobic interactions. B increases with increasing [salt]. C decreases with increasing [salt]. D is independent of G + C content. E increases with increasing pH. 4. The total contour length of DNA in a human cell is about A 1 mm. B 1 mm. C 10 cm. D 1 meter. E 12 furlongs. 5. Polyacrylamide and agarose gel electrophoresis separate nucleic acids based primarily on their A length. B ratio of mass/charge. C (G+C)/(A+T) content. D organismal origin. E content of 15N (buoyant density). 6. The number of supercoils in a covalently-closed, circular DNA can only be changed if A at least one of the phosphodiester chains is cleaved. B both of the phosphodiester chains are cleaved. C histones are bound to the DNA. D the salt concentration is increased >1.0 M
E chemical reagents react with the backbone phosphates 7. Thymidine a is equal to the adenosine concentration in double-stranded DNA b is replaced by Uracil in RNA c normally forms 2 hydrogen bonds with adenosine D can participate in hydrophobic interactions due to its methyl group E All of the above are correct 8. The major and minor grooves of B-form DNA correspond to what features of A-form rNA? a minor and major grooves b deep and shallow grooves D phosphoribose backbones E Choices a) and d)are both correct 9. The glycosid ic bonds in DNA and rna A be hydrolyzed by o b are free to rotate over about 180 c are restricted to one of four possible orientations E stabilize Watson-Crick H-bonds 10. In solution, the grooves of nucleic acid helices a are filled with H2O and counterions(M*& m2t) B expose the H-bonding groups of the bases c expose the hydrophobic surfaces of the bases D are about equal in width E Choices a) and b)are both correct 11. When an aromatic molecule intercalates into the dna double helix the two adjacent base pairs are separated by about and the helix is unwound by about A342,36° B4.3?,36° C3.4?.26° D4.3?,26 E1.7?,10° 12. If your genomic DNA could be typed for a specific genetic defect a "I would not want to be tested ever b "I would want to be tested now C I might want to be tested later
E chemical reagents react with the backbone phosphates. 7. Thymidine A is equal to the adenosine concentration in double-stranded DNA. B is replaced by Uracil in RNA. C normally forms 2 hydrogen bonds with adenosine. D can participate in hydrophobic interactions due to its methyl group. E All of the above are correct. 8. The major and minor grooves of B-form DNA correspond to what features of A-form RNA? A minor and major grooves B deep and shallow grooves C deoxyribose backbones D phosphoribose backbones E Choices a) and d) are both correct. 9. The glycosidic bonds in DNA and RNA A can be hydrolyzed by OH- . B are free to rotate over about 180°. C are restricted to one of four possible orientations. D connect the sugar to the base. E stabilize Watson-Crick H-bonds. 10. In solution, the grooves of nucleic acid helices A are filled with H2O and counterions (M+ & M2+). B expose the H-bonding groups of the bases. C expose the hydrophobic surfaces of the bases. D are about equal in width. E Choices a) and b) are both correct. 11. When an aromatic molecule intercalates into the DNA double helix, the two adjacent base pairs are separated by about ______, and the helix is unwound by about _______. A 3.4?, 36° B 4.3?, 36° C 3.4?, 26° D 4.3?, 26° E 1.7?, 10° 12. If your genomic DNA could be typed for a specific genetic defect A "I would not want to be tested, ever." B "I would want to be tested now." C "I might want to be tested later
D I need much more information before decid ing E All four decisions are now being made by reasonable people ※<2 1. The a-amino acids have a carboxyl group with a pK around and an amino group with a pK near A1.and12.1 B6.5,and8.0. C3.and10.5 D9.0,and2.5 E 2.2 and 9.5 2. Which pair of amino acids absorbs the most UV light at 280 nm? a Thr h B Trp Tvr. C Cys Asp d Phe pro e None of the above 3. Which of the following is not a sensible grouping of amino acids based on their polarity properties? Ala Leu and val B Arg, His, and Lys C Phe, Trp, and Tyr D Asp, Ile, and Pro E Asn. Ser and Thr 4. The isoelectric point of an amino acid is defined as a the ph where the molecule carries no net electric charge. b the ph where the carboxyl group is uncharged c the pH where the amino group is uncharged d the ph of maximum electrolytic mobility E -logio(pKi+ pKj 5. When the amino acid alanine(the R-group is:-CH3)is added to a solution with a pH of7.3, alanine becomes A B C D an Isotope e an anion
D "I need much more information before deciding." E All four decisions are now being made by reasonable people. 5 ※<2> 1. The a-amino acids have a carboxyl group with a pK around ___ , and an amino group with a pK near ___. A 1, and 12.1 B 6.5, and 8.0. C 3, and 10.5. D 9.0, and 2.5. E 2.2 and 9.5. 2. Which pair of amino acids absorbs the most UV light at 280 nm? A Thr & His. B Trp & Tyr. C Cys & Asp. D Phe & Pro. E None of the above. 3. Which of the following is not a sensible grouping of amino acids based on their polarity properties? A Ala, Leu, and Val. B Arg, His, and Lys. C Phe, Trp, and Tyr. D Asp, Ile, and Pro. E Asn, Ser, and Thr. 4. The isoelectric point of an amino acid is defined as A the pH where the molecule carries no net electric charge. B the pH where the carboxyl group is uncharged. C the pH where the amino group is uncharged. D the pH of maximum electrolytic mobility. E -log10(pKi + pKj) 5. When the amino acid alanine (the R-group is: -CH3) is added to a solution with a pH of 7.3, alanine becomes: A a cation. B nonpolar. C a zwitterion. D an isotope. E an anion
6. Aspartic acid is similar to glutamic acid in the same way that a His is similar to pro b Ser is similar to Cys c GIn is similar to asn d Asn is similar to gin e Gly is similar to val 7. Alanine is similar to serine in the same way that a val is similar to Thr b Phe is similar to Tyr c Phe is similar to Trp d Ser is similar to Thr E Trp is similar to Pro 8. Glycine is similar to valine in the same way that a Ala is similar to leu b Thr is similar to met C Ala is similar to lle D Arg is similar to Lys e None of the above are valid similarities 9. A significant difference between His and Pro is that a the His side chain is aromatic, the pro side chain is aliphatIc b His is an a-amino acid Pro is an imino acid c the His side chain has a six-membered ring; Pro has a five-membered ring d the His side chain has a pK around ph=7; the pro side chain does not e All but the third choice are significant d ifferences 10. A significant difference between Phe and Tyr is that a the Phe side chain is aromatic, the Tyr side chain is aliphatic B Tyr is an a-amino acid; Phe is an imino acid c the Tyr side chain has an -OH group: the Phe side chain does not. d the Tyr side chain has a pK around pH=7; the Phe side chain does not e All but the third choice are significant differences ※<3> 1. The peptide bond in proteins a planar, but rotates to three preferred dihedral angles B nonpolar, but rotates to three preferred dihedral angles C nonpolar, and fixed in a trans conformation planar and usually found in a trans conformation. E not cleavable by hydrolysis
6. Aspartic acid is similar to glutamic acid in the same way that A His is similar to Pro. B Ser is similar to Cys. C Gln is similar to Asn. D Asn is similar to Gln. E Gly is similar to Val. 7. Alanine is similar to serine in the same way that A Val is similar to Thr. B Phe is similar to Tyr. C Phe is similar to Trp. D Ser is similar to Thr. E Trp is similar to Pro. 8. Glycine is similar to valine in the same way that A Ala is similar to Leu. B Thr is similar to Met. C Ala is similar to Ile. D Arg is similar to Lys. E None of the above are valid similarities. 9. A significant difference between His and Pro is that A the His side chain is aromatic, the Pro side chain is aliphatic. B His is an a-amino acid; Pro is an imino acid. C the His side chain has a six-membered ring; Pro has a five-membered ring. D the His side chain has a pK around pH = 7; the Pro side chain does not. E All but the third choice are significant differences. 10. A significant difference between Phe and Tyr is that A the Phe side chain is aromatic, the Tyr side chain is aliphatic. B Tyr is an a-amino acid; Phe is an imino acid. C the Tyr side chain has an -OH group; the Phe side chain does not. D the Tyr side chain has a pK around pH = 7; the Phe side chain does not. E All but the third choice are significant differences. 5 ※<3> 1. The peptide bond in proteins is A planar, but rotates to three preferred dihedral angles. B nonpolar, but rotates to three preferred dihedral angles. C nonpolar, and fixed in a trans conformation. D planar, and usually found in a trans conformation. E not cleavable by hydrolysis
2. The molecular formula for glycine is C2HsO2N. What would be the molecular formula for a linear oligomer made by linking ten glycine molecules together by condensation synthesis? A C20H5oO20N, B CoH3 OuN C C20H4OOIoN e None of the above 3. The resonance structures that can be drawn for the peptide bond indicate that the peptide bond a still isn 't completely understood by chemists B is stronger than an ordinary single bond c has partial double bond character d actually extends to the a-carbon e The second and third choices are both correct 4. The peptide hormone involved in controlling blood pressure is a testosterone b oxytocin d interferon B E glutathione 5. Aspartame, the synthetic sweetener(a k a NutraSweet ), is A b also secreted by the posterior pituitary gland in response to thirst c a glucose derivative D not digested (i.e. hydrolyzed) by humans is nearly 10,000-fold sweeter than sucrose, by weight ※<4> 1. The peptide, Val-Lys-Glu-Met-Ser-Trp-Arg-Ala, was digested with cyanogen bromide(CnBr) to produce a Val-Lys Glu-Met-Ser Trp-Arg-Ala B Val-Lys-Glu-Met-Ser-Trp Arg-Ala c Val-Lys-Glu-Met D Val-Lys-Glu Met-Ser-Trp-Arg-Ala E Val-Lys-Glu-Met-Ser Trp-Arg-Ala 2. The same peptide, Val-Lys-Glu-Met-Ser-Trp-Arg-Ala, was digested with
2. The molecular formula for glycine is C2H5O2N. What would be the molecular formula for a linear oligomer made by linking ten glycine molecules together by condensation synthesis? A C20H50O20N10. B C20H32O11N10. C C20H40O10N10. D C20H68O29N10. E None of the above. 3. The resonance structures that can be drawn for the peptide bond indicate that the peptide bond A still isn't completely understood by chemists. B is stronger than an ordinary single bond. C has partial double bond character. D actually extends to the a-carbon. E The second and third choices are both correct. 4. The peptide hormone involved in controlling blood pressure is: A testosterone. B oxytocin. C vasopressin. D interferon B. E glutathione. 5. Aspartame, the synthetic sweetener (a.k.a. NutraSweet), is A a dipeptide. B also secreted by the posterior pituitary gland in response to thirst. C a glucose derivative. D not digested (i.e. hydrolyzed) by humans. E is nearly 10,000-fold sweeter than sucrose, by weight. 5 ※<4> 1. The peptide, Val-Lys-Glu-Met-Ser-Trp-Arg-Ala, was digested with cyanogen bromide (CNBr) to produce A Val-Lys + Glu-Met-Ser + Trp-Arg-Ala. B Val-Lys-Glu-Met-Ser-Trp + Arg-Ala. C Val-Lys-Glu-Met + Ser-Trp-Arg-Ala. D Val-Lys-Glu + Met-Ser-Trp-Arg-Ala. E Val-Lys-Glu-Met-Ser + Trp-Arg-Ala. 2. The same peptide, Val-Lys-Glu-Met-Ser-Trp-Arg-Ala, was digested with