Download 大碩102研究所全真模擬考試試題

大碩102研究所全真模擬考試試題
科
目：分子生物(生化所)
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考試日期：2012/11/24
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I、選擇題(每題2分，80%)
1. In the DNA Double Helix, complementary base pairs are held together by :
(A) N-glycosidic bonds
(B) hydrogen bonds
(C) ionic bonds
(D) peptide bonds
2. A DNA strand has the sequence A-C-A-G-C-C-G-T-A. What would be its complementary strand ?
(A) A-C-A-G-C-C-G-T-A
(B) U-G-U-C-G-G-C-A-U
(C) G-T-G-A-T-T-A-C-G
(D)
T-G-T-C-G-G-C-A-T
3. Every polypeptide chain formed in translation starts with the amino acid:
(A) methionine
(B) lysine
(C) serine
(D) alanine
(E) glycine
4. The Quaternary structure of a protein is :
(A) its structure resulting from interactions between amino acid side chains.
(B) its structure resulting from the union of more than one protein molecule, called subunit proteins.
(C) its structure resulting from hydrogen bonds between the C=O and N-H groups of different amino acids.
(D) its amino acid sequence
5. All of the following conditions promote the denaturation of DNA except
(A) low ionic strength solutions.
(B) high pH.
(C) organic solvents.
(D) high temperature.
(E) extremely low temperature.
6. Which of the following is not a stop codon ?
(A) GUA
(B) UAA
(C) UAG
(D) UGA
7. Infectious self-reproducing agents consisting only of protein, with no nucleic acids (hypothesized in 1982
by Nobel Laureate Stanley B. Prusiner) are called :
(A) exteins
(B) proteomes
(C) proteinoids
(D) Prions
8. Select the correct statement about nucleosome
(A) contains only DNA and nonhistone proteins
(B) has a core of histones with DNA wound around it
(C) is fully responsible for DNA packaging into chromosomes
(D) surround nuclear pores
(E) all nuclear DNA is in regularly spaced nucleosomes
(E) RNaseP
大碩102研究所全真模擬考試試題
科
目：分子生物(生化所)
共
9. In DNA base pairs, A-T pairs are joined by
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H bonds,
whereas G-C pairs are joined by H bonds.
(A) three-----two
(B) two-----three
(C) two-----two
(D) three-----three
(E) none of the
above
10. Put the following steps of E. coli primosome assembly in the correct order.
(1) Primase binds.
(2) DnaA binds to oriC at dnaA boxes.
(3) DnaB binds to the open complex.
(4) DnaA, RNA polymcrase, and HU protein melt the DNA.
(A) 2, 4, 1, 3
(B) 2, 4, 3, 1
(C) 3, 4, 1, 2
(D) 4, 1, 2, 3
(E) 4, 2, 1, 3
11. Which of the following subunits of the DNA polymerase III holoenzyme is referred to as the “sliding
clamp”?
(A) α
(B) β
(C) γ
(D) τ
(E) θ
12. The series of three consecutive mRNA bases coding for one specific amino acid in a protein is called a:
(A) codon
(B) intron
(C) exon
(D) transposon
13. Prokaryotes use 70S ribosomes which consist of :
(A) a (small) 30S and a (large) 50S subunit
40S and a (large) 30S subunit
(B) a (small) 40S and a (large) 60S subunit
(D) a (small) 10S and a (large) 60S subunit
14. The Shine-Dalgarno sequence can be found in
(A) mRNA.
(B) tRNA.
(C) a (small)
(C) SS rRNA.
.
(D) 16S rRNA.
(E) 30S ribosome.
15. Which of the following processes occurs post-transcriptionally?
(A) Cap addition
(B) adenosine deamination
(C) Poly(A) addition
(D) promoter clearance
(E)
unwinding
16. A guanine triphosphate nucleotide that binds to the 5’ end of the mRNA thus increasing the stability of
the synthesized RNA and enhancing translation efficiency is called a :
(A) poly-A-tail
(B) Cap
(C) leader
(D) trailer
(E) telomere
17. An RNA molecule that can catalyze either its own cleavage (self-splicing) or the cleavage of other RNA
molecules is :
(A) An inducer
(B) A ribozyme
(C) A spliceosome
(D) A chaperone enzyme.
大碩102研究所全真模擬考試試題
科
目：分子生物(生化所)
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18. Which of the following molecules serves as a primer for reverse transcriptase during retroviral
replication?
(A) host snRNA
(B) host tRNA
(C) host ribosomal DNA
(D) viral RNA
(E) viral protein
19. Sections of DNA within a gene that do not encode part of the protein that the gene produces are called :
(A) Exons
(B) Transposons
(C) Introns
(D) Intein
(E) operator
20. Please put the following steps of mRNA Cap synthesis in the correct order.
(1) N7 of the capping guanine is methylated.
(2) The terminal phosphate is removed from the pre-mRNA.
(3) A capping GMP is added to the pre-mRNA.
(4) The 2’-O-methyl group of the penultimate nucleotide is methylated.
(A) 1, 2, 3, 4
(B) 1, 4, 3, 2
(C) 2, 4, 1, 3
(D) 2, 3, 1, 4
(E) 4, 3, 2, 1
21. In DNA, mutations at G-C sequences occur quite frequently since 5-methyl cytosine easily deaminates to
form :
(A) Cytosine
(B) Adenine
(C) Guanine
(D) Uracil
(E) Thymine
22. Which of the following statements is not true concerning DNA replication in E. coli?
(A) DNA replication is semiconservative.
multiple origins of replication.
(B) DNA replication is semidiscontinuous.
(D) DNA replication is RNA dependent.
(C) There arc
(E) DNA replication requires
topoisomerase.
23. Which of the following mammalian cell DNA polymerases is not correctly matched with its function?
(A) DNA Pol ε—DNA repair
(B) DNA Pol δ—ligation of DNA strands
(C) DNA Pol γ—elongation of both strands
(D) DNA Pol β—DNA repair
(E) DNA Pol α—priming DNA synthesis
24. An enzyme (used by all retroviruses) that transcribes genetic information of the virus from RNA into
DNA, is :
(A) Reverse transcriptase
(B) RNA polymerase
(C) Restriction nuclease
(D) Methylase
25. Which of the following is the best definition of translation?
(A) a process by which pre-mRNA is transformed into mature mRNA
(B) the process by which pre-mRNA is translated by ribozymes to produce proteins
大碩102研究所全真模擬考試試題
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目：分子生物(生化所)
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(C) a process by which a gene is converted into mRNA
(D) a process by which a gene is converted into a protein
(E) the process by which ribosomes read the genetic message to produce a protein
26. The enzyme responsible for initiating the unwinding of double-stranded DNA (eliminating supercoiling)
by nicking a single strand of the DNA molecule is :
(A) Gyrase
(B) Ligase
(C) Topoisomerase I
(D) Helicase
(E) N-glycosylase
27. Predict the effect of the addition of excess acetyltansferase to in vitro transcription assay.
(A) It will likely loosen the interaction of histone with DNA.
(B) It will lead to a tighter association of histone with DNA, resulting in reduced transcription.
(C) It will have no effect on the interaction of DNA with histones.
(D) There will be a complete repression of transcription.
(E) None of the choices are correct.
28. If Hershey and Chase found S35 in progeny phages rather than P32, their experiment would have
demonstrated that
(A) proteins contain phosphorus.
(B) DNA contains sulfur.
phage protein enters the host cell.
(E) None of the above.
(C) phage DNA enters the host cell.
(D)
29. The enzyme (made of proteins and RNA) that elongates chromosomes by adding TTAGGG sequences to
the end of existing chromosomes is :
(A) Exonuclease
(B) Endonuclease
(C) Telomerase
(D) Amylase
30. Which of the following agents causes DNA damage by forming pyrimidinc dimers?
(A) X-rays
(B) γ-radiation
(C) UV radiation
(D) alkylating agents
(E) ethidium bromide
31. Which of following codons would not be recognized by release factors during translation?
(A) AUG
(B) UAG
(C) UAA
(D) UGA
(E) none of the above.
32. Which of the following is true about the action of CAP at the lac promoter?
(A) CAP monomer binds directly to the promoter then stimulates polymerase to bind.
(B) CAP blocks the aCTD of RNA polymerase.
(C) CAP-AMP blocks recruitment of polymerase to the promoter.
(D) Binding of the CAP-cAMP to the lac activator-binding site recruits RNA polymerase.
(E) None of the above choices is correct.
大碩102研究所全真模擬考試試題
科
目：分子生物(生化所)
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33. Which of the following repair mechanisms is a damage bypass mechanism, not an actual repair
mechanism?
(A) DNA photolyase
(B) base excision repair
(C) nonhomologous end joining
(D) mismatch repair
(E) recombination repair
34. In the Meselson and Stahl experiment, what percentage of the DNA is labeled with light nitrogen after
three generations of replication?
(A) 25%
(B) 50%
(C) 75%
(D) 100%
(E) None of the above.
35. The poly(A) tail of eukaryotic mRNA is approximately
(A) 1000
(B) 250
(C) 100
(D) 25
nucleotides in length
(E) 5
36. Please put the following steps of Cap synthesis in the correct order.
(1) N7 of the capping guanine is methylated.
(2) The terminal phosphate is removed from the pre-mRNA.
(3) A capping GMP is added to the pre-mRNA.
(4) The 2’-O-methyl group of the penultimate nucleotide is methylated.
(A) 1, 2, 3, 4
(B) 1, 4, 3, 2
(C) 2, 4, 1,3
(D) 2, 3, 1,4
(E) 4, 3, 2, 1
37. Choose a right statement on Telomerase or Telomere
(A) Telomerase was first observed in Tetrahymena micronuclei extracts.
(B) Telomerase is a unique enzyme in that it is composed of only RNA.
(C) Without telomeres, linear eukaryotic chromosomes would get shorter and shorter with each round of
DNA replication
(D) All organisms must protect their telomeres from nucleases and double strand break repair enzymes.
38. EF-Tu is an important protein in cells whose function is to
(A) properly fold proteins.
(B) ensure proper ribosome assembly.
(C) escort aminoacyl-tRNA to the ribosome.
(D) protect rRNA from degradation by RNases.
(E) stabilize mRNA within the ribosome.
39. Cells in G0 phase
(A) can be stimulated to enter S phase
dividing tissues
(B) have the tetraploid amount of DNA
(D) must accumulate division potential before entering M phase
(C) occur in rapidly
大碩102研究所全真模擬考試試題
科
目：分子生物(生化所)
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40. Which of the following techniques can not be used to quantify the level of gene expression?
(A) Northern blotting
(B) Southern blotting
(C) S1 mapping
(D) Nuclear run-off
RNase protection
II、問答題(20%)
1. List three major differences between DNA and RNA structures. (6%)
2. Describe two ways how DNA polymerases control the fidelity of replication. (4%)
3. Please list three differences of mRNA between E. coli and Homo sapiens. (5%)
4. Which DNA polymerase provides the priming function in eukaryotes? Which DNA polymerases are
replicases in mammals? What are the functions of MCM, Cdc6, PCNA, RFC and FEN1? (5%)
(E)