所屬科目：研究所、轉學考(插大)◆分子生物學
1. Which chemical bonds contribute to the thermodynamic stability of the DNA double helix and the specificity of base pairing? (A) Covalent bonds. (B) Van der Waals bonds. (C) Hydrogen bonds. (D) Ionic bonds. (E) Hydrophobic bonds.
2. Which process takes place during the anaphase of mitosis? (A) Bivalent attachment. (B) Condensation of chromosomes. (C) Cytokinesis. (D) Proteolysis of cohesion. (E) Re-formation of nuclear envelope.
3. Which of the following statements is correct regarding DNA replication? (A) Okazaki fragments are formed on the leading strand. (B) Initiation of DNA synthesis requires an RNA primer. (C) DNA helicases remove supercoils at the replication fork. (D) DNA polymerase I mainly functions in prokaryotic DNA replication. (E) DNA ligases stabilize the separated strands.
4. During DNA replication, the ssDNA-binding proteins (SSBs): (A) are typically found more on the leading strand than on the lagging strand. (B) prevent the folding of the single-stranded DNA. (C) cover the bases to prevent base-pairing. (D) interact with ssDNA in a sequence-dependent manner. (E) form a lot of hydrogen bonds with the phosphate backbone.
5. Which histone is NOT a component of nucleosome core particle? (A) H1. (B) H2A. (C) H2B. (D) H3. (E) H4.
6. Which kind of DNA damage occurs most frequently under normal physiological conditions? (A) Alkylation. (B) Acetylation. (C) Methylation. (D) Deamination. (E) Formation of thymine dimer.
7. Which statement is correct regarding the function of the enzyme involved in the RecBCD pathway in Escherichia coli? (A) RecBCD recognizes Holliday junctions. (B) RuvC induces double-strand breaks. (C) RecA facilitates strand invasion. (D) Rad51 catalyzes the resolution of Holliday junctions. (E) RuvAB generates single strands for invasion.
8. Exchange of genetic material between cells by direct cell-to-cell contact is called: (A) conjugation. (B) injection. (C) infection. (D) transformation. (E) transduction.
9. Which eukaryotic RNA polymerase transcribes tRNA genes? (A) RNA polymerase I. (B) RNA polymerase II. (C) RNA polymerase III. (D) RNA polymerase IV. (E) RNA polymerase V.
10. Which of the following types of noncoding RNA mainly functions in the processing and chemical modification of ribosomal RNAs (rRNAs)? (A) Small interfering RNAs (siRNAs). (B) Small nuclear RNAs (snRNAs). (C) Small nucleolar RNAs (snoRNAs). (D) Piwi-interacting RNAs (piRNAs). (E) Small rDNA-derived RNAs (srRNAs).
11. How does Rho-independent termination work? (A) RNA polymerase recognizes an RNA element (rut site) and stops transcription. (B) RNA forms a stem-loop structure that disrupts the elongation complex. (C) A poly-A signal sequence recruits poly-A polymerase and signals termination. (D) A repressor facilitates detachment of RNA polymerase from the RNA-DNA duplex. (E) RNase H hydrolyzes the phosphodiester bonds of RNA in the RNA-DNA duplex.
12. Among the three binding sites for tRNA in ribosomes, the P-site: (A) is the binding site for the aminoacylated-tRNA. (B) is the binding site for the tRNA that is released. (C) holds the tRNA linked to the growing polypeptide chain. (D) is the first location to which the t-RNA binds during the protein synthesis process. (E) moves the tRNA to the E-site when a stop codon is reached.
13. Polysome profiling involves mRNAs with different numbers of associated ribosomes separated by: (A) reverse phase chromatography. (B) ion exchange chromatography. (C) mass spectrometry. (D) sucrose gradient centrifugation. (E) sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).
14. Which consensus sequence is involved in the initiation of translation in prokaryotes? (A) Shine-Dalgarno sequence. (B) Kozak sequence. (C) Okazaki sequence. (D) -35 element. (E) TATA element.
15. During the RNA editing process, deamination of cytosine results in its conversion to: (A) adenine. (B) guanine. (C) inosine. (D) thymine. (E) uracil.
16. Which region of tRNA is responsible for base pairing between tRNA and mRNA? (A) Acceptor stem. (B) Variable loop. (C) Anticodon loop. (D) D loop. (E) YU loop.
17. How does nonsense suppression work? (A) Point mutation of the nucleotide close to the nonsense codon. (B) RNA editing on the nonsense codon. (C) Insertion of a nucleotide during the gene replication. (D) Mutation of a tRNA so that it can bind with the nonsense codon. (E) Mutation of a release factor so that it cannot terminate translation.
18. What is the inducer of the lac operon and binds to the Lac repressor? (A) Lactose. (B) Glucose. (C) IPTG. (D) X-gal. (E) GABA.
19. The first codon of mRNA translated by a ribosome is typically: (A) UGA. (B) GUA. (C) AGU. (D) AUG. (E) AAA.
20. Which of the following statements is correct regarding imprinting? (A) Imprinting follows the rules of Mendelian inheritance. (B) Histone acetylation is responsible for imprinting. (C) Maintenance methyltransferase is involved in the imprinting process. (D) Sickle cell disorder is a disorder associated with imprinting. (E) Maintenance of the lysogenic state via cell division is an example of imprinting.
21. The λ repressor encoded by the cI gene can act as a repressor or an activator. How does the λ repressor act as an activator to stimulate transcription of the cI gene? (A) It binds to OR2 and contacts RNA polymerase at PRM to stimulate transcription. (B) It binds to OR3 and contacts RNA polymerase at PR to stimulate transcription. (C) It binds to OL2 and contacts RNA polymerase at PLM to stimulate transcription. (D) It binds to OL3 and contacts RNA polymerase at PL to stimulate transcription. (E) It binds to ORE and contacts RNA polymerase at PRE to stimulate transcription.
22. Which of the following nucleotides is hydrolyzed in both transcription and in translation elongation? (A) ATP. (B) CTP. (C) GTP. (D) TTP. (E) UTP.
23. Which of the following do NOT typically interact with an elongating RNA polymerase II? (A) Histone-modifying enzymes. (B) Chromatin remodeling complexes. (C) Mediator complexes. (D) Capping enzymes. (E) Histone chaperones.
24. An enhancer: (A) is a trans-acting sequence that stimulates transcription. (B) cannot activate a promoter upstream from this same enhancer. (C) can be located at any distance from a promoter. (D) activates a promoter via an insulator between the enhancer and the promoter. (E) directly interacts with RNA polymerase II to stimulate transcription.
25. Which enzyme is generally linked to transcriptional activation in eukaryotes? (A) Histone methyltransferase. (B) Histone acetyltransferase. (C) Histone phosphorylase. (D) Histone demethylase. (E) Histone deacetylase.
26. Which enzyme is responsible for transcriptional silencing in eukaryotes? (A) DNA methylase. (B) DNA acetylase. (C) DNA polymerase. (D) DNA ligase. (E) DNA endonuclease.
27. The five RNAs (U1, U2, U4, U5, and U6) identified in the spliceosome are: (A) small nucleolar RNAs (snoRNAs). (B) small nuclear RNAs (snRNAs). (C) small interfering RNAs (siRNAs). (D) long non-coding RNAs (lncRNAs). (E) small rDNA-derived RNAs (srRNAs).
28. Which of the following statements is correct regarding DNA transposition? (A) Autonomous transposons cannot move in the absence of nonautonomous transposons. (B) Virus-like retrotransposition involves target-site-primed reverse transcription. (C) RNA-mediated transposition involves insertion of RNA into a new target site. (D) Transposase cleaves the 5' ends of the element DNA and leaves the 3' terminating strands uncut. These strands are called the nontransferred strands. (E) Replicative transposition results in cointegration with 2 copies of transposon.
29. Which of the following features is true regarding telomerase? (A) It carries its own DNA template. (B) It adds a repeat sequence to the 5' end of telomeres. (C) Its activity is high in somatic cells and low in most cancer cells. (D) It relocates after polymerization reaches the end of the template. (E) It shortens the length of telomeres and leads to disastrous results.
30. During the embryonic development, homeotic genes: (A) determine the dorsal-ventral polarity. (B) control the number of body segments. (C) encode morphogens that establish gradients. (D) are usually expressed by the mother during oogenesis. (E) are defined by mutations that convert one anatomical structure into another.
31. Which of the following components are usually absent in the processed pseudogene that arises from integration of reverse-transcribed mRNAs? (A) Exon. (B) Intron. (C) Poly-A tail. (D) Promoter. (E) 3' untranslated region.
32. Which of the following mutation types may lead to frameshift mutation? (A) Point mutation. (B) Insertion. (C) Deletion. (D) Substitution. (E) Missense mutation.
33. Which of the following features are true regarding tyrosine recombinases? (A) They introduce double-strand breaks. (B) They introduce Holliday junctions. (C) They cleave all four DNA strands before strand exchange. (D) They break and rejoin one pair of DNA strands at a time. (E) They include the Cre recombinase that recognizes the loxP site.
34. Which of the following statements are correct regarding RNA splicing? (A) Release of group I introns is catalyzed by spliceosomes. (B) An intron is spliced out through two transesterification reactions. (C) The 5' splice site is recognized by the U1 snRNP. (D) Group II introns are the most commonly used for eukaryotic genes. (E) Group I introns release a linear intron.
35. Which statements are correct regarding the expression of the lac operon? (A) Genes in the lac operon are expressed at high levels when both lactose and glucose are present at high levels. (B) The site bound by the lac repressor is called the lac operator. (C) The lac repressor is expressed regardless of whether or not lactose is present. (D) The lac operon is not transcribed when neither the activator nor the suppressor binds its site on DNA. (E) Catabolite activator protein (CAP) binds to the CAP site when glucose is absent.
36. Which steps take place during the establishment and maintenance of lysogeny? (A) The N and cro genes are transcribed, but the cII and cIII genes are not transcribed. (B) The CII protein binds a site upstream from PRE. (C) The repressor protein stimulates transcription of the cI gene and binds OR and OL. (D) The Cro protein binds OR and stimulates transcription of the cro and cII genes. (E) The Q protein helps the RNA polymerase to transcribe through TR'.
37. Which rRNAs are included in the eukaryotic ribosomes? (A) 5S rRNA. (B) 16S rRNA. (C) 18S rRNA. (D) 23S rRNA. (E) 28S rRNA.
38. Which are correct regarding riboswitches that regulate translation initiation? (A) These riboswitches are typically found within the 3' untranslated region. (B) Each riboswitch is made up of an aptamer and an expression platform. (C) The aptamer undergoes structural changes in response to the changes in the expression platform. (D) The ribosome-binding site is typically found in the expression platform. (E) The ligand-binding site is typically found in the aptamer.
39. Which of the following statements are correct regarding RNA silencing? (A) Small interfering RNAs (siRNAs) are derived from hairpin precursor RNAs. (B) MicroRNAs (miRNAs) are derived from double-stranded RNAs. (C) Both siRNAs and miRNAs are generated by the enzyme called Dicer. (D) The small RNA complement to the target mRNA is called the passenger RNA. (E) RNA-dependent RNA polymerase can enhance the efficiency of RNA silencing.
40. Synthetic biology is defined as a field of science that involves redesigning organisms for useful purposes using the concept of forward engineering. According to this definition, which of the following studies are considered as synthetic biology? (A) Biosynthesis of artemisinic acid in yeasts. (B) Production of p53 mice to analyze the effect of p53 on tumor formation. (C) Design of light-sensing gene regulatory circuits in Escherichia coli. (D) Establishment of an Arabidopsis T-DNA insertional mutant collection. (E) Synthesis of a minimal bacterial genome.
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