107年 - 107 長庚大學_碩士班招生考試試題_生命醫學研究所碩士班：分子生物學#126156

1. When a repressor binds to the operator site on the DNA it normally______.(A) terminates transcription that has already been initiated.(B) inhibits the initiation of transcription.(C) reduces the rate of transcription.(D) has no effect on transcription.

2. Posttranslational regulation occurs after a protein has been synthesized, and can occur by______. (A) covalent modification. (B) allosteric regulation. (C) feedback inhibition. (D) allosteric regulation and covalent modification are both means of regulation after translation is complete.

3. Which of the following can lead to transition mutations? (A) A small insertion or deletion. (B) Incorporation of a base analog that exhibits different base-pairing properties from the base it replaces. (C) Chemical modification of an existing base in the DNA so that in the next round of replication it will pair differently from the unmodified base. (D) Incorporation of a base analog that exhibits different base-pairing properties from the base it replaces and chemical modification of an existing base in the DNA so that in the next round of replication it will pair differently from the unmodified base.

4. Which of the following types of mutation may play an important role in driving evolution because they are often nonlethal and, therefore, remain in the gene pool? (A) nonsense (B) frameshift (C) missense (D) deletion

5. The process in which one or more nucleic acid molecules are rearranged or combined to produce a new nucleotide sequence is called________. (A) recombination. (B) transformation. (C) conjugation. (D) transduction.

6. When a eukaryotic gene is cloned into a bacterium, the advantage of a complementary DNA (CDNA) gene being used instead of fragments of genomic DNA is that_____.(A) the promoter and terminator are found in the cDNA gene but not in the genomic fragment. (B) the cDNA is made with the nucleotides found in the prokaryote but not in the eukaryote. (C) the introns have been removed from the cDNA gene but not from the genomic fragment. (D) there is no advantage to using a cDNA gene rather than a genomic fragment.

7. DNA microarray technology is used to measure the_____.(A) DNA content of cells.(B) levels of specific proteins expressed by cells.(C) levels of specific RNAs expressed by cells.(D) genetic complexity of cells of interest.

8. Which of the following best describes the basis for separation of DNA fragments during agarose gel
electrophoresis?(A) The fragments with the highest percentage of G and C will migrate fastest.(B) The fragments with the highest percentage of A and T will migrate fastest.(C) The largest fragments will migrate fastest.(D) The smallest fragments will migrate fastest.

9. T4 DNA Ligase is used to?(A) Ligate 2 proteins together.(B) Ligate 2 RNAs together.(C) Ligate 2 ends of DNA together.(D) None of the above

10. "Reverse Transcription" describes which process?(A) mRNA to Protein(B) Folded protein to unfolded protein(C) DNA to mRNA(D) mRNA to DNA

11. Which of the following experimental techniques can NOT be used to detect RNA levels?(A) Western blot(B) Northern blot(C) RT-PCR(D) RNase protection assay

12. Which of the following type of RNA is transcribed by RNA pol II?(A) tRNA(B) rRNA(C) snRNA(D) mRNA

13. You perform a PCR reaction and find that there is an extra band in addition to the band of the expected size. Which of the following changes to the protocol has the best chance to eliminate the extra band? (A) Raising the annealing temperature (B) Increasing the time of the denaturation step (C) Shortening the time of the elongation step (D) Decreasing the number of cycles performed

14. Mutations in which of the following regions of a gene is most likely to cause disruption of gene function?(A) 3'UTR(B) 5'UTR(C) Polyadenylation signal(D) Coding sequence

15. Which of the following techniques can NOT be used to test interaction between two proteins?(A) Yeast two-hybrid(B) Immunoprecipitation(C) Southern blot(D) Fluorescence resonance energy transfer

16. Which of the following statement describes an epigenetic mechanism of regulating gene expression?(A) Regulation of mRNA abundance by miRNAs(B) Activation of transcription through increasing histone acetylation(C) Blocking access of RNA polymerase II to a promoter by a co-repressor(D) Targeting of a protein for degradation with ubiquitination

17. Which description is correct?(A) DNA polymerase can synthesize DNA in both the 3'5' and 5'→3' directions.(B) DNA replication in E. coli is initiated at multiple sites.(C) DNA replication in eukaryotes is initiated at a unique site.(D) DNA ligase cannot link two single-stranded DNA fragments.

18. There are three types of RNA polymerases in eukaryotes. Which description is NOT correct?(A) RNA polymerase I synthesize 5S rRNA.(B) RNA polymerase II synthesizes mRNA.(C) RNA polymerase II synthesizes snRNA.(D) RNA polymerase III synthesizes tRNA.

19. Functions of RNA polymerase includes____________.(A) Searching for promoter sites.(B) Unwinding short stretches of DNA.(C) Detecting termination signals.(D) All of the above.

20. Most genes in higher eukaryotes are composed of exons and introns. The introns must be excised in a process called RNA splicing. Which description is correct? (A) Yeast has no RNA splicing. (B) The consensus sequence at the 5' splice site is AG. (C) The 5' and 3' splice sites and the branch site are essential for RNA splicing. (D) Six snRNAs-designated U1, U2, U3, U4, U5, U6-are essential for RNA splicing.

21. Which description is not correct about tRNA molecules?(A) All are single-stranded RNAs.(B) About half of the nucleotides are base-paired.(C) They contain a lot of unusual bases.(D) The 3' terminal residues are usually CAA.

22. Ribosome biogenesis is the process of making ribosomes, it take place in the______.(A) Nucleoplasm.(B) Nucleolus.(C) Cytoplasm.(D) None of the above.

23. The lac operon is a common regulatory unit in prokaryotes. Which description is NOT correct?(A) When glucose is present, the lac operon is turned off.(B) When lactose is absent, the lac operon is turned off.(C) When lactose is present, the lac operon is turned on.(D) IPTG induces the lac operon by binding to the promoter.

24. Gene expression can be controlled at post-transcriptional levels. Which description is NOT correct?(A) The 5' capping protects the mRNA from degradation by exonuclease.(B) The mRNA splicing occurs only when transcription is fully completed.(C) The 3' polyadenylation has effects on mRNA stability.(D) RNA interference functions in the cytoplasm.

25. Select the correct statement about enhancers.(A) They are proteins that promote transcription of RNA.(B) They stimulate the binding of repressor to DNA.(C) They bind protein factors and stimulate transcription.(D) They are nonpromoter protein elements.

26. Which of the following techniques is most useful in determining if RNA polymerase has initiated transcription from the lac DNA template? (A) Southern analysis (B) DNA fingerprinting (C) run-off transcription assay (D) DNA sequencing

27. Which of the following is NOT present in the core RNA polymerase?(A)β(B) β'(C) σ(D) None of the above.

28. Which of the following approaches would you use to loosen the interaction of the histones with DNA in an extract that you have prepared? (A) methylate the DNA (B) methylate the histone (C) acetylate the histones (D) phosphorylate the histones

29. One method used by researchers to demonstrate the existence of nucleosome free DNA regions is ________.(A) RNA Polymerase Run-off experiments. (B) Nuclear Run on experiments. (C) Reporter gene experiments. (D) DNase hypersensitivity experiments.

30. You need to design PCR primers to amplify following gene, what will your PCR primers look like?
5'ATCGACCTAGATCGCAGCTCGTAGTCGATGTCA........GCTAGCTGTGCTAGCTGATGCTAAATCGATCGAT-3'(A) Forward: 5'-ATCGACCTAGATCGCAGC-3' Reverse: 5'-GATGCTAAATCGATCGAT-3'(B) Forward: 5'-ATCGACCTAGATCGCAGC-3' Reverse: 5'-ATCGATCGATTTAGCATGA-3'(C) Forward: 5'-GCTGCGATCTAGGTCGAT-3' Reverse: 5'-GATGCTAAATCGATCGAT-3'(D) Forward: 5'-GCTGCGATCTAGGTCGAT-3' Reverse: 5'-ATCGATCGATTTAGCATGA-3

31. Which of the following is NOT true ? (A) The coding sequence (CDS) is the actual region of DNA that is translated to form proteins. (B) An open reading frame (ORF) is the DNA sequence between translation start codon and stop codon. (C) In eukaryotic cell, the ORF may longer than CDS because ORF may contain introns as well. (D) There are three possible ways of translating nucleotide sequence into amino acid sequence according to the genetic code. These are called reading frames.

32. Which of the following is NOT true? (A) Because DNA polymerases polymerize DNA only in the 5'-to-3' direction, synthesis of the lagging strand at a replication fork must occur discontinuously through a backstitching mechanism that produces short DNA fragments. (B) When the replication fork reaches an end of a linear chromosome: there is no place to produce the RNA primer needed to start the last Okazaki fragment at the very tip of a linear DNA molecule. (C) In human, telomeres consist of many tandem repeats of a short sequence that contains a block of GGGTTA, extending for about 10,000 nucleotides. (D) The telomerase synthesizes a new copy of the repeat, using a loop-back protruding single-stranded DNA template from another strand.

33. Which of the following is NOT true about proteasome? (A) Proteasome contains abundant ATP-dependent proteases. (B) Present in many copies dispersed throughout the cytosol and the nucleus. (C) Each proteasome consists of a central hollow cylinder formed from multiple protein subunits. (D) The proteasomes act on proteins that have been specifically marked for destruction by the covalent attachment of multiple copies of selectin.

34. Which of the following assay can be used to detect sequence-specific DNA binding protein?(A) Gel-Mobility Shift Assay(B) DNA Affinity Chromatography(C) Chromatin Immunoprecipitation(D) All of the above

35. Approximately what fraction of the human genome are exons of all genes?(A) 1%(B) 10%(C) 25%(D) 50%

36. 2. BamHI has a restriction site of G↓GATCC while Hpal has a restriction site of GTT ACC. Based upon this, BamHI produces____________ and Hpal produces__________.(A) a 5'overhang; a 3'overhang (B) a 5'overhang; blunt ends (C) a 3'overhang; a 5'overhang (D) a 3'overhang; blunt ends 

37. The histone core of a nucleosome is consisted of_______.(A) one copy each of histones H1, H3 and H4(B) two copies each of H1, H3 and H4,(C) one copy each of H2A, H2B, H3 and H4(D) two copies each of H2A, H2B, H3 and H4.

38. Which of the following exonuclease activities is present in DNA polymerase I?(A) 3'exonuclease that degrades double stranded DNA(B) 3'exonuclease that degrades hairpin DNA(C) 5'exonuclease that degrades single stranded DNA(D) 5'exonuclease that removes RNA from a DNA-RNA duplex

39. Which of the following the represents the correct sequence of events for the Holiday model of homologous recombination? (A) nicking, strand invasion, branch migration, ligation, crossed strand breakage, rejoining (B) nicking, strand invasion, branch migration, crossed strand breakage, ligation, rejoining (C) nicking, strand invasion, ligation, branch migration, crossed strand breakage, rejoining (D) nicking, strand invasion, ligation, branch migration, isomerization, crossed strand breakage, rejoining

40. In order for lysogeny to occur, the enzyme________must insert the phage DNA into a specific site in the bacterial chromosome.(A) ligase(B) lysogenase(C) helicase(D) integrase