山东大学分子生物学相关资料.doc

Section A - Cells and macromolecules 1The glycosylation of secreted proteins takes place in the . . .A mitochondria. B peroxisomes. C endoplasmic reticulum. D nucleus. 2Which of the following is an example of a nucleoprotein?A keratin. B chromatin. C histone. D proteoglycan.3Which of the following is not a polysaccharide? A chitin. B amylopectin. C glycosaminoglycan.D glycerol. 4. Transmembrane proteinsA join two lipid bilayers together. B have intra- and extracellular domains. C are contained completely within the membrane. D are easily removed from the membrane.Section B - Protein structure1. Which of the following is an imino acid? A proline. B hydroxy lysine. C tryptophan. D histidine. 2 Protein family members in different species that carry out the same biochemical role are described as . . . A paralogs. B structural analogs. C heterologs. D orthologs. 3. Which of the following is not a protein secondary structure?A -helix.B triple helix. C double helix. D -pleated sheet. 4 In isoelectric focusing, proteins are separated .A in a pH gradient. B in a salt gradient. C in a density gradient. D in a temperature gradient.5Edman degradation sequences peptides . . . A using a cDNA sequence. B according to their masses. C From the C-terminus to the N-terminus. D from the N-terminus to the C-terminus. Section C - properties of nucleic acids1The sequence 5-AGTCTGACT-3 in DNA is equivalent to which sequence in RNA? A 5-AGUCUGUGACU -3 B 5 -UGTCTGUTC -3 C 5 -UCAGUCUGA-3 D 5- AGUCAGACU-3 2. Which of the following correctly describes A-DNA? A a right-handed antiparallel double helix with 10 bp/turn and bases lying perpendicular to the helix axis. B a left-handed antiparallel double-helix with 12 bp/turn formed from alternating pyrimidine-purine sequences. 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.A preakage 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?A double-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? A the DNA is circular. B the DNA is packaged into nucleosomes.C the DNA is contained in the nucleus. D the DNA is negatively supercoiled. 2A compl 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. 3In what region of the interphase chromosome does transcription take place? A the telomere. B the centromere. C euchromatin. D heterochromatin. 4 Which statement about CpG islands and methylation is not true? A CpG 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. 5Which of the following is an example of highly-repetitive DNA? A Alu element. B histone gene cluster. C DNA minisatellites. D dispersed repetitive DNA. Section E - DNA replication1The number of replicons in a typical mammalian cell is . . . A 40-200. B 400. C 1000-2000. D 50000-100000. 2. In prokaryotes,the lagging strand primers are removed by . . . A 3 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 . . . A DnaA. B DnaB. C DnaC. D DnaE. 4. Which phase would a cell enter if it was starved of mitogens before the R point? A G1. B S. C G2. D G0. 5. Which one of the following statements is true? A once the cell has passed the R point, cell division is inevitable. B the phosphorylation of Rb by a G1 cyclin-CDK complex is a critical requirement for entry into S phase . C phosphorylation of E2F by a G1 cyclin-CDK complex is a critical requirement for entry into S phase. D cyclin D1 and INK4 p16 are tumor suppressor proteins. 6. In eukaryotes, euchromatin replicates predominantly. A in early S-phase. B in mid S-phase. C in late S-phase. D in G2-phase. 7. Prokaryotic plasmids can replicate in yeast cells if they contain a cloned yeast. . . A ORC. B CDK. C ARS. D RNA. Section F - DNA damage, repair and recombination1. Per nucleotide incorporated, the spontaneous mutation frequency in E. coli is . . . A 1 in 106. B 1 in 108. C 1 in 109. D 1 in 1010. 2. The action of hydroxyl radicals on DNA generates a significant amount of . . . A pyrimidine 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. Illegitimate recombination is another name for . . . A site-specific recombination. B transposition.C homologous recombination.D translesion DNA synthesis. 5. 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 G - Gene manipulation1. The presence of a plasmid in a bacterial culture is usually determined by . . . A blue-white screening. B growth in the presence of an antibiotic. C a restriction enzyme digest. D agarose gel electrophoresis. 2. The enzyme alkaline phosphatase. . . A the take-up of a plasmid into a bacterium. B the expression of a gene in a bacterium.C the take-up of a bacteriophage into a bacterium.D the isolation of a plasmid from a bacterium. 3. Transformation is . . . A the take-up of a plasmid into a bacterium. B the expression of a gene in a bacterium.、 C the take-up of a bacteriophage into a bacterium. D the isolation of a plasmid from a bacterium. 4. T4 DNA ligase . . . A requires ATP. B joins double-stranded DNA fragments with an adjacent 3-phosphate and 5-OH. C requires NADH. D joins single-stranded DNA.5. In agarose gel electrophoresis . . . A DNA migrates towards the negative electrode. B supercoiled plamids migrate slower than their nicked counterparts. C larger molecules migrate faster than smaller molecules.D ethidium bromide can be used to visualize the DNA. Section H - Cloning vectors 1. Blue-white selection is used. . . A to test for the presence of a plasmid in bacteria. B to reveal the identity of a cloned DNA fragment. C to express the product of a cloned gene. D to test for the presence of a cloned insert in a plasmid. 2. A multiple cloning site . . . A contains many copies of a cloned gene. B allows flexibility in the choice of restriction enzymes for cloning. C allows flexibility in the choice of organism for cloning. D contains many copies of the same restriction enzyme site. 3. Infection of E. coli by bacteriophage is normally detected by . . . A resistance of the bacteria to an antibiotic. B the growth of single bacterial colonies on an agar plate. C the appearance of areas of lysed bacteria on an agar plate. D restriction digest of the bacterial DNA. 4. Which vector would be most appropriate for cloning a 150 kb fragment of DNA? A a plasmid. B a vector. C a BAC. D a YAC. 5. Which vector would you chqose to express a foreign gene in a plant? A a baculovirus vector. B a retroviral vector. C a Yep vector. D a T-DNA vector. Section I - Gene libraries and screening 1. Which two of the following statements about genomic libraries are false? A genomic libraries are made from cDNA. B genomic libraries must be representative if they are to contain all the genes in an organism. C genomic libraries must contain a minimum number of recombinants if they are to contain all the genes In an orgamsm. D the DNA must be fragmented to an appropriate size for the vector that is used. E genomic libraries made from eukaryotic DNA usually use plasmid vectors. 2. Which statement correctly describes sequential steps in cDNA cloning?A reverse transcription of Mrna second strand synthesis cDNA end modification ligation to vector. B mRNA preparation cDNA synthesis using reverse transcriptase second strand synthesis using terminal transferase, ligation to vector. C mRNA synthesis using RNA polymerase reverse transcription of mRNA, second strand synthesis, ligation to vector. D double stranded cDNA synthesis restriction enzyme digestion addition of linkers ligation to vector. 3. Which one of the following is not a valid method of screening a library? A hybridization of colony / plaque-lifted DNA using a nucleic acid probe. B using antibodies raised against the protein of interest to screen an expression library. C screening pools of clones from an expression library for biological activity. D hybridization of colony/plaque-lifted DNA using an antibody probe. Section J - Analysis and uses of cloned DNA 1. A linear DNA fragment is (100%) labeled at one end and has 3 restriction sites for EcoRI. If it is partially digested by EcoRI so that all possible fragments are produced how many of these fragments will be labeled and how many will not be labeled? A 4 labeled; 6 unlabeled. B 4 labeled; 4 unlabeled. C 3 labeled: 5 unlabeled. D 3 labeled; 3 unlabeled. 2. Which of the following are valid methods of labeling duplex DNA? A 5-end labeling with polynucleotide kinase. B 3-end labeling with polynucleotide kinase. C 3-end labeling with terminal transferase.D 5-end labeling with terminal transferase.E nick translation. 3. Which one of the following statements about nucleic acid sequencing is correct? A the Sanger method of DNA sequencing involves base specific cleavages using piperidine. B the Maxam and Gilbert method of DNA sequencing uses a DNA polymerase and chain terminating dideoxynucleotides. C enzymatic sequencing of RNA uses RNases A, T1, Phy M and B. cereus RNase. D enzymatic sequencing of DNA uses a primer which is extended by an RNA polymerase.E enzymatic sequencing of RNA uses RNases T1, U2, Phy M and B. cereus RNase. 4. Which one of the following statements about peR is false? A the PCR cycle involves denaturation of the template，annealing of the primers and polymerization of nucleotides. B PCR uses thermostable DNA polymerases. C ideally PCR primers should be of similar length and G+C content. D PCR optimization usually includes varying the magnesium concentration and the polymerization temperature. E if PCR was 100% efficient, one target molecule would amplify to 2n after n cycles. 5. Which two of the following statements about gene mapping techniques are true? A S1 nuclease mapping determines the nontranscribed regions of a gene. B primer extension determines the 3-end of a transcript. C gel retardation can show whether proteins can bind to and retard the migration of a DNA fragment through an agarose gel. D DNase I footprinting determines where on a DNA fragment a protein binds. E the function of DNA sequences in the promoter of a gene can be determined if they are ligated downstream of a reporter gene and then assayed for expression. 6. Which one of these statements about mutagenesis techniques is false? A exonuclease III removes one strand of DNA in a 5 to 3 direction from a recessed 5-end. B exonuclease III removes one strand of DNA in a 3 to 5 direction from a recessed 3-end.C mutagenic primers can be used in PCR to introduce base changes.D mutagenic primers can be used with a single stranded template and DNA polymerase to introduce base changes.E deletion mutants can be created using restriction enzymes. 7. Which one of these statements about the applications of gene cloning is false?A large amounts of recombinant protein can be produced by gene cloning.B DNA fingerprinting is used to detect proteins bound to DNA. C cloned genes can be used to detect carriers of disease-causing genes. D gene therapy attempts to correct a disorder by delivering a good copy of a gene to a patient.E genetically modified organisms have been used to produce clinically important proteins. Section K - Transcription in prokaryotes 1. Which two of the following statements about transcription are correct? A RNA 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 3 direction. 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? A the 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 transcription in E. coli is true? A the -10 sequence is always exactly 10 bp upstream from the transcription start site.B the initiating nucleotide is always a G. C the intervening sequence between the -35 and -10 sequences is conserved. D the sequence of the DNA after the site of transcription initiation is not important for transcription efficiency. E the distance between the -35 and -10 sequences is critical for transcription efficiency. 5. Which one of the following statements about transcription in E. coli is true? A loose binding of the RNA polymerase core enzyme to DNA is non-specific and unstable. B sigma factor dramatically increases the relative affinity of the enzyme for correct promoter sites.C almost all RNA start sites consist of a purine residue, with A being more common than G. D all promoters are inhibited by negative supercoiling. E terminators are often A-U hairpin structures. Section L - Regulation of transcription in prokaryotes 1. Which two of the following statements are correct? A the double stranded DNA sequence that has the upper strand sequence 5-GGATCGATCC-3 is a palindrome. B the double stranded DNA sequence that has the upper strand sequence 5-GGATCCTAGG-3 is apalindrome. C the Lac repressor inhibits binding of the polymerase to the lac promoter. D the lac operon is directly induced by lactose. E binding of Lac repressor to allolactose reduces its affinity for the lac operator.F IPTG is a natural inducer of the lac promoter. 2. Which one of the following statements about catabolite-regulated operons is false?A cAMP receptor protein (CRP) and catabolite activator protein (CAP) are different names for the same protein. B when glucose is present in the cell cAMP levels fall. C CRP binds to cAMP and as a result activates transcription.D CRP binds to DNA in the absence of cAMP. E CRP can bend DNA, resulting in activation of transcription. 3. Which one of the following statements about the trp operon is true? A the RNA product of the trp operon is very stable. B the Trp repressor is a product of the trp operon. C the Trp repressor， like the Lac repressor, is a tetramer of identical subunits. D the Trp repressor binds to tryptophan. E tryptophan activates expression from the trp operon. F the trp operon is only regulated by the Trp represso4. Which two of the following statements about attenuation at the trp operon are true? A attenuation is rho-dependent. B deletion of the attenuator sequence results in an increase in both basal and activated levels of tran- scription from th trp promoter. C the attenuator lies upstream of the trp operator sequence. D attenuation does not require tight coupling between transcription and translation. E pausing of a ribosome at two tryptophan codons in the leader peptide when tryptophan is in short supply causes attenuation. F a hairpin structure called the pnti-terminator stops formation of the terminator hairpin, resulting in transcriptional read-through into the trpE gene, when tryptophan is scarce.5. Which two of the following statements about sigma factors are false? A the E. co