Section C - properties of nucleic acids1. The sequence 5-AGTCTGACT-3 in DNA is equivalent to which sequence in RNA?A 5-AGUCUGUGACU -3B 5 -UGTCTGUTC -3C 5 -UCAGUCUGA-3D 5- AGUCAGACU-32. Which of the following correctly describes A-DNA?A a right-handed antiparallel double helix with 10 bp/turn and bases lying perpendicular tothehelix axis.B a left-handed antiparallel double-helix with 12 bp/turn formed fromalternating pyrimidine-purinesequences.C a right-handed antiparallel double helix with 11 bp/turn and bases tilted with respect to the helix axis.D a globular structure formed by short intramolecular helices formed in a single-strand nucleic acid.3. Denaturation of double stranded DNA involves. Abreakage into short double-stranded fragments.B separation into single strands.C hydrolysis of the DNA backbone.D cleavage of the bases from the sugar-phosphate backbone.4. Which has the highest absorption per unit mass at a wavelength of 260 nm? Adouble-stranded DNA.B mononucleotides.C RNA.D protein.5. Type I DNA topoisomeraes . A change linking number by 士 2 B require ATP.C break one strand of a DNA double helix.D are the target of antibacterial drugs.Section D - Prokaryotic and eukaryotic chromatin structure1Which of the following is common to both E. coli and eukaryotic chromosomes? Athe DNA is circular.B the DNA is packaged into nucleosomes.C the DNA is contained in the nucleus.1D the DNA is negatively supercoiled.2A complex of 166 bp of DNA with the histone octamer plus histone HI is known as a . . .A nucleosome core.B solenoid.C 30 nm fiber.D chromatosome.3. In what region of the interphase chromosome does transcription take place? Athe telomere.B the centromere.C euchromatin.D heterochromatin.4. Which statement about CpG islands and methylation is not true? ACpG islands are particularly resistant to DNase I.B CpG methylation is responsible for the mutation of CpG to TpG in eukaryotes.C CpG islands occur around the promoters of active genes.D CpG methylation is associated with inactive chromatin.5. Which of the following is an example of highly-repetitive DNA? AAlu element.B histone gene cluster.C DNA minisatellites.D dispersed repetitive DNA.Section E - DNA replication1. The number of replicons in a typical mammalian cell is . . . A40-200.B400.C1000-2000.D50000-100000.2. In prokaryotes,the lagging strand primers are removed by . . . A3 to 5 exonuclease.B DNA ligase.C DNA polymerase I.D DNA polymerase III.3. The essential initiator protein at the E. coli origin of replication is . . . ADnaA.B DnaB.C DnaC.D DnaE.4. Prokaryotic plasmids can replicate in yeast cells if they contain a cloned yeast. . . AORC.B CDK.C ARS.D RNA.Section F - DNA damage, repair and recombination(此章不考)1. Per nucleotide incorporated, the spontaneous mutation frequency in E. coli is . . . A1 in 106.B1 in 108.C1 in 109.D1 in 1010.2. The action of hydroxyl radicals on DNA generates a significant amount of . . . Apyrimidine dimmers.B 8-oxoguanine.C O6- methylguanine.D 7-hydroxymethylguanine.3. In methyl-directed mismatch repair in E. coli, the daughter strand containing the mismatched base is nicked by . . .A MutH endonuclease.B UvrABC endonuclease.C AP endonuclease.D 3 to 5 exonuclease.4. The excision repair of UV-induced DNA damage is defective in individuals suffering from .A hereditary nonpolyposis colon cancer.B Crohns disease.C classical xeroderma pigmentosum.D xeroderma pigmentosum variant.Section K - Transcription in prokaryotes1. Which two of the following statements about transcription are correct? ARNA synthesis occurs in the 3 to 5 direction.B the RNA polymerase enzyme moves along the sense strand of the DNA in a 5 to 3direction.C the RNA polymerase enzyme moves along the template strand of the DNA in a 5 to 3 direction.D the transcribed RNA is complementary to the template strand.E the RNA polymerase adds ribonucleotides to the 5 end of the growing RNA chain.F the RNA polymerase adds deoxyribonucleotides to the 3 end of the growing RNA chain.2. Which one of the following statements about E. coli RNA polymerase is false? Athe holoenzyme includes the sigma factor.B the core enzyme includes the sigma factor.C it requires Mg2+ for its activity.D it requires Zn2+ for its activity.3. Which one of the following statements is incorrect?A there are two subunits in the E. coli RNA polymerase.B there is one subunit in the E. coli RNA polymerase.C E. coli has one sigma factor.D the subunit of E. coli RNA polymerase is inhibited by rifampicin.E the streptolydigins inhibit transcription elongation.F heparin is a polyanion, which binds to the subunit.4. Which one of the following statements about transcriptio