Bacteriology 303- Exam 4- Spring 05 B

Bacteriology 303- Exam 4- Spring 05 B - EXAM4,html \ i _ A...

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Unformatted text preview: EXAM4,html \ i _ A ' y . PageloflO t Bacteriology 303 University of Wisconsin-Madison . Fourth Examination May 5, 2005 The following sequence of nucleotide bases lies‘within the encoding region of the gene for tetracycline ' t ' S h loco * 1. Reading left to right, what is the sequence of the first five nucleotide bases in the DNA complementary to the strand of DNA illustrated? ' A. CUGUU} ' >B. CATTC ' - 17"“ C. CAGAA , , . _ a - D. GUCUU E. GTCTT . .2. Transcribing the DNA strand from left to right_(disregard polarity), What is the mRNA nucleotide sequence transcribed from the segment of DNA above? . - ' - ' - A. GUCUUUAGAAUG V B; GTCTTTAGAATG - . v ' , _ = g} C. CAGAAAUCUUAC ' ‘ D. GUAAGAUUUCUG E. none of the above 3. During translation, the amino acid sequence encoded by the DNA sequence illustrated above would be ' - ' ' ' A. cys-arg-glu-arg ' , ‘: - A B. gly-met—ser—phe - C. val-phe-arg-met , ' . - v . D. trp-val-arg-phe E. met-arg-phe-val 4. If DNA base #104 was changed from A to G, the amino acid encoded by the corresponding RNA codon would be ' q , ' . A. arg _ ' . B. cys ' , I _ , . C. glu ' -. ' - - - ' D. ser "My ' E."fi0fié’0f’the’ab3vefi 7'7"" 7 "W’W’WWW’iVW‘ 5. The situation described in-question 4 is an example of (a) http://www.bact.wisc.edu/Bact3 03/Exam4. * v . ' 5/6/2005 ~ I ‘ . a EXAM4.html . . W " 3 . Page2of10 A. point mutation B. silent mutation - . :- C. degeneracy of the genetic code ' - fl? D. all of the above . ' E. none of the above 6. Ifthe base C were inserted between ’base 105 and base 106 the third amino acid encoded by this sequence would be A. arg ' ' ' B. glu ‘ , . C. met K D. phe E. none of the above ' 7. The situation described in question 6 is an example of (a) A. . base substitution B. missense (terminator) mutation ~ . , C. frame shift mutation ' - ' ' ' a ‘ D. misreading of the genetic code - . . . - ‘ : _ E. degeneracy of the genetic code ‘ ' ' l 8. What is the most likely phenotypic consequence of a point mutation (eg. base substitution)in a bacterial gene that encodes for a particular enzyme? ’ - ‘ A. No enzyme is produced. . p B. An enzyme is produced with no change in primary structure or activity. C. A truncated (shortened ) protein is produced which lacks enzymatic activity. -' ' D D. The enzyme produced has an altered primary structure and may or may not show any alteration in activity. ‘ _ . 3 ' E. The enzyme produced exhibits no change in primary structure but has altered activity. 9. Which of the following is the most likely event to occur during transcription and translation of a gene '- that has undergone a frame-shift mutation early in the encoding Sequence for a specific protein? A. Transcription of the entire gene is blocked because RNA polymerase cannot bind to its promoter in the gene. - - - ‘ 'B. Translation is blocked because ribosomes cannot bind-to the transcript (mRNA) of the gene. I . C. Transcription is halted at the point of the mutation. - ' . f - D. TranscriptiOn is halted downstream of the point of the mutation. . E. A complete transcript (mRNA) of the gene is produced, but an error (terminator or stop codon) encountered during translation trunCates (shortens) the protein. ' i - 10. In the Lederberg and Tatum experiment which provided the first evidence of genetic exchange in I bacteria, thepurpose in using triple auxotrophs of the mating strains of E. coli was to ' 5 A. minimize the development of revertants which would be indistinguishable from recombinants _ ’ B. distinguish conjugation from transformation _ I . A. C. distinguish transduction from transformation ' - - ' D. . prove that conjugation required cell—to—cell contact a _ , prove thatjhegatesrofmuteninnwhich,inrrolved asinglebaSe change,,(i.e.,-a, substitinnmutation).-.An.V W--. were equal to the rates of reversion , ll. In. the Zinder and Lederberg U-tube experiment, DNAase was added to the U¥tube‘to inhibit the ' http://www.bact.wisc.edu/Bact303/Exam4‘ ’ ' . - 5/6/2005 ' EXAM4hth ' Page 3 of 10 bacterial process of A. translation . , ' _ _ B. transformatiOn . C. lysogeny ' a D. conjugation ' E. transduction 12. What was the outcome of the Griffith experiment when killed encapsulated cells of Streptococcus pneumoniae were mixed with living nonencapsulated cells, then injected into mice? ' A. Mice were not killed and living nonencapsulated cells were recovered. B. Mice were killed and living nonencapsulated cells were recovered. C. Mice were killed and living encapsulated cells were recovered. ‘ l D. Mice were not killed and no bacteria could be recovered. - ' E. none of the above 13. The genetic acquisition of multiple drug resistance in Shigella as a result of conjugation with E. coli is an example of ‘ ' I .A. lysogenc conversion B. natural selection _ _ C. genetic reversion ‘ ' ‘ ' .' I. D. vertical evolution ‘ - - ~ _ . _ ' if E. horizontal evolution -‘ ' l4. Similarities between bacteriophage lambda DNA and the F factor in E. coli include A. They are genetic elements that are replicated in the bacterial host. B. They may contain genes removed from the bacterial chromosome. C. They may integrate into the bacterial chromosome. » D. They may be transferred horizontally from a donor to recipient during the processes of genetic exchange, _ E. all of the above 15. During the, process of restricted (specialized) transduction A. lysogenic bacteriophages are required B. only genes linked to the prophage DNA are transferred from a donor to recipient I El/W C. the prophage makes an imperfect excision from the bacterial chromosome before replicating and lysing the host cell ‘ a D. two of the above E. all of the above . 16. The F factor may be considered an episome because , A. it can exist free in the cytoplasm or it may integrate into the bacterial chromosome . B. it may be substituted with genes which encode drug resistance ' I C. it encodes for the genetic information involved in its own transfer ' -‘ 4 D. it is a self-replicating genetic factor ' . - ' B. it encodes for dispensable genetic information ‘ A. insertion elements onvthe F fifefior V—i . K _ B. transmissible plasmids with genes that encode drug resistance ' C. transposons that move from place to place on the bacterial chromosome ' 17. Resistance transfer factors (RTFs) in bacterjaiarem _ 7 7 7 , W 7 WV , W ,, We, ,- mm- ‘http://www.baCt.wisc.edu/Bact3'03/Exam4 ' p . i ' 5/6/2005 EXAM4.html ‘ " r _ p - ' Page4 of 10 D. chromosomal genes for the “synthesis of antibiotics E. genetic factors that prevent the transfer of drug resistance among mating strains ' 18. The penicillin enrichment (penicillin selection) technique is useful when isolating auxotrophic mutants (for example 317—) because penicillin . A. acts as a mutagen and thereby increases the rate of mutation toward trp auxotrophy B. does not affect eukaryotic cells ' . . ~ C. does not affectE. 0011' under the conditions of the experiment ' ‘ - D. kills the growing wild-type bacteria, not the nongrowing mutantsin the population E. causes lysis of the wild—type Which release tryptophan that allows the trp- mutants to grow 19. Which one of the following strains of E. 6011' would be able to conjugate with ' - . E. 6011' F— met — arg— B I — to produce a recombinant that grows on minimal medium supplemented with Vitamin B1? ' A. F+ met+ arg+ BI - . ‘ - B. F+met+ arg+ B] + a 4 ~ I . p. ’ C. Hfr met - arg— B] '+ . ’ D. Hfr met+ arg+ BI - ' E. none of the above ‘ 20. Which one of the following strains of E. coli would be able to conjugate with E. coli F- 1717‘. leu-' Lac - to produce a recombinant that grows on minimal medium with lactose as a sole source of carbon? A. _ F + trp+ Zeu— Lac.+ B. F+ tr'p— leu+ Lac+ . . . p C. Hfrlrp+leu+Lac— , - . v . fl - ' ~ . D. Hfr trp+ leu+_ Lac+ t .- ' - ' D E. Hfr Zr'p— leu— Lac+ 21. T 719— mutants (tryptophan auxotrophs) can be isolated from the wild type (er+) by A. direct plating on medium containing tryptophan ‘ . B. direct plating on medium without tryptophan - ‘ a C. replica plating from a medium without tryptophan to-a medium with tryptophan - D D. replica plating from a medium with tryptophan to a medium without tryptophan ‘ ' ' a E. two of the above ‘ , -~ . ' 22. Trp+ revertants (prototrophs) could be isolated from a population of trp- mutants by A. direct plating on medium containing tryptophan , > ' B. direct plating on medium without tryptophan . ‘ " x C. penicillin, enrichment in a medium which contains tryptophan . .D. penicillin enrichment in a medium lacking tryptophan E. two of the above ‘ ' 23. The following experiment was done: 2 x108 cells of strain A of a bacterium requiring the amino ’ acid proline and the vitamin biotin were mixed with 2 x 108 cells of strain B which requires the amino acids methionine and leucine. After 30 minutes of incubation, the mixture was spread at various dilutions onto plates of minimal medium (containing glucose as the only organic substance). After rdvéffii’g'lifificfibatianil 1707601Ofiiésvfiefé'obtaifiéd’bn’ the platéi’cbhfaifiiifigwailO‘lidilutiOn, and’24'661'oni'esm ' on the plate containing a 10‘2 dilution and no colonies at a 10'3 dilution. Which of the following conclusions from the experiment is correct? > http://www.bact.wisc.edu/Bact3 O3/Exam4 ’ * . * 5/6/2005 r, ' p i. . ' ' r r p I I » Page 5 of 10 . A. Genetic recombination has not occurred between the two strains of bacteria. . B. The rate of genetic recombination between the two strains of bacteria is approximately 10'5 I C. The rate of mutation to proline auxotrophy is 10'7 V ' i >) D. The rate of reversion to methionine prototrophy is '10‘4 E. none of the above Questions 24—27 refer to the following set of experimental data. 5 X 108 cells of each of two strains of Salmonella thimurizmz, one which is 6315- his— and SMr, and the other which is arg— met — and SMs, are mixed in a tube. After 30 minutes, the mixture is plated onto various media and the following results after growth are noted: ‘ ' Minimal medium (glucose plus inorganic salts): no colonies Minimal medium plus Arg: 100 colonies . ' Minimal medium plus His: 10 colonies Minimal medium plus Arg and SM: no colonies - Minimal medium plus Arg, Met and SM: 100 colonies Arg = arginine Cys = cysteine His = histidine Met = methiOnine . SM = streptomycin (r = resistant; s = sensitive) Yes . . - . _ i ' ' ' ‘ N. no ' ' v ' I . __ can't tell ' ' _ Has genetic recombination taken place between the two strains of bacteria? .. yes_ . fi ca'n'ttell I ' _ ' fir was‘! 26.‘ What mutation. in one strain of the bacteria is indicated by the results of this experiment? 0310.“ m, g .. «rise {4 A. streptomycin resistance (SMs-—.---> SMr) ' ’ I \‘5‘ B. arginineauxotrophy (arg+-----> arg-) . C. histidine auxotrophy (his+—---—> his-) . . . D. all of the above ‘ ' > - fl E. none of the above " “ - 27. What reversion in one strain of bacteria is indicated by the results of the experiment? A. streptomycin sensitivity (SMr—----> SMs) B. arginine prototrophy (arg ---- -—> arg+)' ‘ C. methionine prototrophy (met - ----> met +) ‘ . y ' / D. all of the above ‘ ‘ C, E. none of the above 28. An environmental scientist wants to determine if two chemicals, IX and Y, are possible mutagens. The Ames Test is employed using a his— strain of Salmonella Whimurizmz. The following results are http://www.bact.wisc.edu/Bact303/Exam4 _ . 5/6/2005 EXAM4.html Page 6 of 10 obtained: NUMBER OF REVERTANT (his+)‘ COLONIES Chemical Control Plate Test Plate X 247 230 ' Y 32 208 The conclusion from these results is: A. X is a possible mutagen; Y is probably not a mutagen . _ B. X is probably not a mutagen; Y probably is a mutage'n v i ’ » ' B C. both X and Y are probable mutagens D. neither X nor Y are mutagens none of the abOve 29. Suppose the tetracycline-resistant (Tor) gene from Shigella and the the ampicillin-resistant (Ampr) gene of S. aureus were transformed into a strain of E. coli which is sensitive to the two antibiotics. In _, order to determine if the transformation was successful, what medium should be used to detect the transformants? A. minimal medium with no supplements . B. minimal medium plus ampicillin _ ‘ - ' I C. minimal medium plus tetracycline .' D. minimal medium plus ampicillin and tetracycline E. none of the above ’30. A bacterial geneticist mixes 109 cells of E. coli strain A which requires lysine and is ampicillin sensitive with 109 cells of strain B which requires phenylalanine and tyrosine and is ampicillin resistant. ‘ In order to detect whether genetic recombination had occurred between the two strains it would be best to grow the mixture of cells in _ A. minimal glucose medium plus ampicillin ‘ . _ - B. minimal glucose medium plus lysine and phenylalanine ‘ - C. minimal glucose medium plus lysine and tyrosine ' ' ' V D. minimal glucose medium plus phenylalanine, tyrosine and ampicillin E. minimal glucose medium with no supplements ' 31. In order to obtain a lysine revertant from strain A (above) the culture should be plated on _ A. minimal glucose medium plus ampicillin ' l B. minimal glucose medium plus lysine and phenylalanine , V C. minimal glucose medium plus phenylalanine and tyrosine ' F D. minimal glucose medium plus lysine and ampicillin E. minimal glucose medium with no supplements '32. 109 cells of each of two strains of Bacillus subzilis, one which is cys- his-5 and PCI, and the other which is arg- met - and PCs, are mixed in a tube; After 30 minutes, the mixture is plated onto various media and the following results after growth are noted: ' Minimal medium (glucose plus inorganic salts): no colonies h/Iiniifialifemuifi plifi’arvgzil0’5’coloniesm "w v P” Minimal medium plus his: .11 colonies . Minimal medium plus arg and PC: no colonies Minimal medium plus arg, met and PC: 104 colonies http://WWW.bact:wisc.edu/Bact3 03/Exam4 5/6/2005 EXAMzmmir ‘ W . ,' 7, 7-7 Page7of10 . . ‘ arg =. arginine cys = cysteine his = histidine met = methionine PC = penicillin (r = resistant; s = sensitive) . I The results of the experiment suggest that ' A. Genetic recombination did not take place between the two strains of bacteria. B. The rate of reversion to cysteine prototrophy (cys+) is 10'8 C. The rate of reversion to methionine prototrophy (met+) is 10'7' _ I r D. The frequency of mutation from PCs to PCr is approximately 10'7 E. all of the above ‘ ‘ ' 33. Viruses are classified (taxonomically) by the following criteria: A. - type of nucleic acid. I ' V , I B. rib'osomal size ' i - ' . _ C. type of energy producing metabolism . ' . V .. D.' whether or not their genome is enclosed in a nuclear membrane E. all of the above ' ’ ’ 3.4. The term "host range" of a virus refers to ' ' ‘ . ' 1 A. whether the virus infects specifically plants, animals or bacteria ‘ B. whether the virus infects certain species of animals, but not others V _‘ ' C. Whether the virus infects only specific genera or bacteria ' ' ‘ C D. whether then virus infects only certain types of cells within a plant or animal ' E. all of the above 35. ' Replication of virulent animal viruses and lytic-bacteriophages in their respective host cells differs most strikingly at this step. ' A. attachment * a B. penetration _ - ' p s , . ~ g C. synthesis of early proteins ' v ' ' r ' ' . ~ D. synthesis of "late proteins E. assembly of coat proteins 36. The tail and related structures of a bacteriophage such as T2 or lambda A. are composed of proteins distinct from cap‘somere proteins . p _ B. are involved in attachment and penetration of viral DNA H I ' C. may package the enzyme lysozyme for involvement in infection - ' D; are examples of late proteins produced during a lytic infection E. all of the above 37. Which of the following statements concerning reproduction of a double-stranded DNA phage such as T4 is not true? ' ' ' '. i A. the viral DNA encodes the information necessary for its own replication . . B. replication of the viral genome utilizes the host cell DNA polymerase ' _ TV ‘ ""Gf theihostcellprovides ribosomes andenergy’for translatijon’ofviral’proteins f" ” "’ W” " ”""’*’ ’ D. late proteins produced during the infection cycle include the enzyme lysozyme E. the release of viruses occurs during host cell lysis http://www.bact.wisc.edu/Bact303/Exam4 5/6/2005 EXAM4.hha1 ’ r ' 7 Page 8 '0in 3 8. During replication of a lytic phage in a susceptible bacterial cell, the early proteins translated from early phage mRNA are concerned with ' ' - A. attachment of the phage to its host cell B. entry of the phage nucleic acid into the host cell I ' . . “a . » C. replication of the phage nucleic acid C,» D. phage assembly E. lysis of the host cell 39. During the replication of a lysogenic phage‘ in its specific. host cell, the late proteins are involved in A. integration of prophage DNA into host DNA 1 B. excision of prophage DNA from host DNA I 4 p y ' C. replication of the phage nucleic acid ' V ' ' . " D. phage assembly and escape from its host cell = " E. two of the above ‘ The obvious similarity between lysogeny of E. coli by phage lambda and transformation of an ' 'iiiiimal cell by Herpes virus is I A. virus DNA is incorporated into host cell DNA 1 - , . B. a DNA copy of the viral RNA is incorporated into host cell DNA . . ‘ I V C. host cells are lysed ' ' D. host cells exhibit loss of contact inhibition E. two of the above ' 41. The similarity between lysOgenic‘conversion of a bacterial cell and transformation of an animal cell ‘ is . A. the cells express a new phenotype ‘ ' . ' H 1 ' ' B. DNA is transferred between cells of different phenotypes ' ’ ' - 4 C. the cells lose the ability to divide and undergo a programmed cell death D. protein synthesis is blocked in the cells I ‘ E. Viability of the cells is'dependent on the presence of a virus With virulent (lytic) single stranded RNA viruses the most typical type of replication involves the ' production of a replicative form consisting of double-stranded RNA. Iftheviral RNAserve's as' mRNA it is designated as +RNA and the complementary strand is designated as I V , ‘ ' ‘ -RNA. Ifthe +RNA serves as messenger and the viral genome is single stranded +RNA what is the ’ function of the -RNA? ' _ ‘ ' - A. template for translation of viral early proteins V , ‘_ ' B. template for translation of viral late proteins . y ’ _ C C. template for replication of +RNA ' ' ' "u D. incorporation into viral capsid E. two of the above - Virulent single stranded —RNA Viruses also produce a replicative form consisting of double-stranded RNA. During viral replication what is the function of the +RNA molecule? ' A. template for translation of viral proteins - _ B. template for replication of +RNA -' I ' ' ‘ ' ' template far production 9.f.3:/: (dleNA, . ' ' ' D. incorporation into viral capsid ' E. all of the above ' http://www.bact.wisc.edu/Bact3 O3/Exam4 ' ' _ - 5/6/2005 7 EXAM4.html 44. Oncogenic viruses are . A. viruses that can transform normal animal cells into tumor cells B. dsRNA viruses that infeCt both plant and animal cells C. viruses theat cause progressive neurological diseases such as multiple sclerosis D. defective viruses that can replicate their nucleic acid in a host cell but which do not encode their own protein coat - y . . E. viruses which can switch between latent and virulent (lytic) infections depending upon the immune status of their host 45. Retroviruses are ssRNA-cOntaining viruses that . A. have evolved from plant cells but which are able to infect animal cells B. encode for a replicase enzyme (vRNAp) that copies +RNA into ~RNA (T ' C. contain atranscriptase enzyme in their core that copies —RNA into +RNA D. utilize an enzyme derived from the host to copy -RNA into +RNA . E. utilize a reverse transcriptase enzyme to copy their RNA genome into a moleCule of dsDNA 46. Proteins in the core of the'HIV nucleocapsid, encoded by the HIV pol genes include A. GP120 ‘ B. CD4 ‘ - C. nucleOcapsid proteinspl7 and p24 D. reverse transcriptase, integrase and protease ' E. none of the above ' 47. What is the primary receptor on T cells for attachment and and entry of HIV ? A. GP'lZO ' ‘ B. GP4O C. CD4 D. CD8 F. HBEGF receptor 48. During the replication cycle of HIV in an infected cell A. reverse transcriptase is involved in the synthesis of provirus DNA B. viral proteins are incorporated into the host cell membrane C. viral mRNA is trancribed using the host cell RNA polymerase D. viral proteins are translated from viral mRNA messages E. all of the above 49. How does HIV infection lead to immunodeficiency in the host? A. TH cells are killed and lysed during viral replication. B. TH cells displaying- GP120 on their surfaces merge with uninfected cells forming multinucleate merged cells called syncytia, which are non functional. . - C. Infected T cells bearing viral proteins are killed by standard antiviral activities of the immune system. \ D. Uninfected T-cell cells which have bound soluble GP120 are attacked by the immune system. B. all of the above . prevents viral entry into susceptible cells - B. prevents uncoating of the viral nucleocapsid following infection of a susceptible cell C. prevents replication of viral nucleic acid in infected cells V http://www.bact.wisc.edu/Bact3 O3/Exam4 Page 9 of 10 ‘ What is the actigngfggmmé}iQthQIOQ;9l11l¥951§91i9%fi0n? W 7477444 ~ v 7 ~* ‘ 4 L7 5/6/2005 I . ’EXAM4hnn1 D. prevents transcription of Viral DNA in infected'cells E. prevents translation of Viral proteins in infected cells http://www.bact.wisc.edu/Bact3 03/Exam4 , Page ‘10, oflO 5/6/2005 rm.a.. ‘ A ...
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Bacteriology 303- Exam 4- Spring 05 B - EXAM4,html \ i _ A...

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