Ch 8 micro

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XQWCat
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176678
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Ch 8 micro
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2012-11-17 23:28:26
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ch 8 micro test 2
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  1. A gene is best defined asA) A segment of DNA.B) Three nucleotides that code for an amino acid.C) A sequence of nucleotides in DNA that codes for a functional product.D) A sequence of nucleotides in RNA that codes for a functional product.E) A transcribed unit of DNA.
    C
  2. Which of the following pairs is mismatched?A) DNA polymerase – makes a molecule of DNA from a DNA templateB) RNA polymerase – makes a molecule of RNA from an RNA templateC) DNA ligase – joins segments of DNAD) Transposase – insertion of DNA segments into DNAE) DNA gyrase – coils and twists DNA
    B
  3. Which of the following statements is false?A) DNA polymerase joins nucleotides in one direction only.B) The leading strand of DNA is made continuously.C) The lagging strand of DNA is started by an RNA primer.D) DNA replication proceeds in one direction around the bacterial chromosome.E) Multiple replication forks are possible on a bacterial chromosome.
    D
  4. DNA is constructed ofA) A single strand of nucleotides with internal hydrogen bonding.B) Nucleotides bonded A–C and G–T.C) Two strands of nucleotides running antiparallel.D) Two strands of identical nucleotides with hydrogen bonds between them.E) None of the above.
    C
  5. Which of the following is NOT a product of transcription?A) A new strand of DNA  B) rRNA  C) tRNA  D) mRNA  E) None of the above
    A
  6. Which of the following statements about bacteriocins is false?
    A) The genes coding for them are on plasmids.B) They cause food-poisoning symptoms.C) Nisin is a bacteriocin used as a food preservative.D) They can be used to identify certain bacteria.E) Bacteriocins kill bacteria.
    B
  7. An enzyme produced in response to the presence of a substrate is calledA) An inducible enzyme.B) A repressible enzyme.C) A restriction enzyme.D) An operator.E) A promoter.
    A
  8. When glucose is high, cAMP is ________ : CAP ________ bind the lac operator, and RNA polymerase ________ bind the lac promoter. A)   low, doesn’t, doesn’tB)   high, does, doesC)   low, doesn’t, doesn’tD)   high, doesn’t, doesE)   low, does, does
    C
  9. Transformation is the transfer of DNA from a donor to a recipient cellA) By a bacteriophage. B) As naked DNA in solution.C) By cell-to-cell contact.D) By crossing over.E) By sexual reproduction.
    B
  10. Genetic change in bacteria can be brought about byA) Mutation.B) Conjugation.C) Transduction.D) Transformation.E) All of the above.
    E
  11. Which of the following statements is false regarding a bacterium that is R+?A) It possesses a plasmid.B) R+ can be transferred to a cell of the same species.C) It is resistant to certain drugs and heavy metals.D) It is F+.E) R+ can be transferred to a different species.
    D
  12. The initial effect of ionizing radiation on a cell is that it causesA) DNA to break.B) Bonding between adjacent thymines.C) Base substitutions.D) The formation of highly reactive ions.E) The cells to get hot.
    D
  13. According to the operon model, for the synthesis of an inducible enzyme to occur, theA) End-product must not be in excess.B) Substrate must bind to the enzyme.C) Substrate must bind to the repressor.D) Repressor must bind to the operator.E) Repressor must not be synthesized.
    C
  14. Synthesis of a repressible enzyme is stopped byA) The allosteric transition.B) The substrate binding to the repressor.C) The corepressor binding to the operator.D) The corepressor-repressor binding to the operator.E) The end-product binding to the promoter.
    D
  15. The damage caused by ultraviolet radiation isA) Never repaired. B) Repaired during transcription.C) Repaired during translation.D) Cut out and replaced.E) Repaired by DNA replication.
    D
  16. Conjugation differs from reproduction because conjugationA) Replicates DNA.B) Transfers DNA vertically, to new cells.C) Transfers DNA horizontally, to cells in the same generation.D) Transcribes DNA to RNA.E) Copies RNA to make DNA.
    C
  17. The necessary ingredients for DNA synthesis can be mixed together in a test tube. The DNA polymerase is from Thermus aquaticus, and the template is from a human cell. The DNA synthesized would be most similar toA) Human DNA.B) T. aquaticus DNA.C) A mixture of human and T. aquaticus DNA.D) Human RNA.E) T. aquaticus RNA.
    A
  18. The mechanism by which the presence of glucose inhibits the arabinose operon isA) Catabolite repression.B) Translation.C) DNA polymerase.D) Repression.E) Induction.
    A
  19.  The mechanism by which the presence of arabinose controls the arabinose operon isA) Catabolite repression.B) Translation.C) DNA polymerase.D) Repression.E) Induction.
    E
  20. If you knew the sequence of nucleotides within a gene, which one of the following could you determine with the most accuracy?A) The primary structure of the proteinB) The secondary structure of the proteinC) The tertiary structure of the proteinD) The quaternary structure of the proteinE) Can't tell
    A
  21. An enzyme that makes covalent bonds between nucleotide sequences in DNA is
    A) RNA polymerase.B) DNA ligase.C) Restriction enzyme.D) Transposase.E) DNA polymerase.
    B
  22. An enzyme that copies DNA to make a molecule of RNA isA) RNA polymerase.B) DNA ligase.C) Restriction enzyme.D) Transposase.E) DNA polymerase.
    A
  23. An enzyme that cuts double-stranded DNA at specific nucleotide sequences.A) RNA polymeraseB) DNA ligaseC) Restriction enzymeD) TransposaseE) DNA polymerase
    C
  24. Repair of damaged DNA might be viewed as a race between an endonuclease andA) DNA ligase.B) DNA polymerase.C) Helicase.D) Methylase.E) Primase.
    D
  25. The cancer gene ras produces mRNA containing an extra exon that includes a number of UAA codons. Cancer cells produce ras mRNA missing this exon. This mistake most likely is due to a mistake byA) A chemical mutagen.B) DNA polymerase.C) Photolyases.D) snRNPs.E) UV radiation
    D
  26. In transcription,A) DNA is changed to RNA.B) DNA is copied to RNA.C) DNA is replicated.D) RNA is copied to DNA.E) Proteins are made.
    B
  27. Assume the two E.coli strains shown below are allowed to conjugate.Hfr:  pro+, arg+, his+, lys+, met+, ampicillin-sensitive
    F:  pro-, arg-, his-, lys-, met-, ampicillin-resistantWhat supplements would you add to glucose minimal salts agar to select for a recombinant cell that is lys+, arg+, amp-resistant?A) Ampicillin, lysine, arginineB) Lysine arginineC) Ampicillin, proline, histidine, methionineD) Proline, histidine, methionineE) Ampicillin, prolein, histidine, lysine
    C
  28. Protein synthesis in eukaryotes is similar to the process in prokaryotes in that both eukaryotes and prokaryotesA) Have exons.B) Have introns.C) Require snRNPS.D) Use methionine as the “start” amino acid.E) Use codons to arrange amino acids.
    E
  29. Transfer of DNA from a donor to a recipient cell by a bacteriophage
    a) conjugation 
    b) transcription 
    c) transduction 
    d) transformation 
    e) translation
    c
  30. Transfer of DNA from a donor to a recipient as naked DNA in solution. 
    a) conjugation  b) transcription  c) transduction  d) transformation e) translation
    d
  31. Feedback inhibition differs from repression because feedback inhibition
    a) is less precise
    b) is slower acting
    c) stops the action of preexisting enzymes
    d) stops the synthesis of new enzymes
    e) all of the above
    c
  32. Bacteria can acquire antibiotic resistance by all of the following except
    a) mutation
    b) insertion of transposons
    c) conjugation
    d) snRNPs
    e) trasnformation
    d
  33. Suppose you inoculate three flasks of minimal salts broth with E coli.  Flask A contains glucose.  Flask B contains glucose and lactose.  Flask C contains lactose.  After a few hours of incubation, you test the flasks for the presence of B-galactosidase.  Which flask(s) do you predict will have this enzyme? 
    a) A  b) B  c) C  d) A and B  e)  B and C
    c
  34. Plasmids differ from transposons in that plasmids
    a) become inserted into chromosomes
    b) are self-replicated outside the chromosome
    c) move from chromosome to chromosome
    d) carry genes for antibiotic resistance
    e) none of the above
    b
  35. Mechanism by which the presence of glucose inhibits the lac-operon
    a) catabolite repression 
    b) DNA polymerase 
    c) induction 
    d) repression 
    e) translation
    a
  36. Mechanism by which the presence of glucose controls the lac-operon  a) catabolite repression  b) DNA polymerase  c) induction  d) repression  e) translation
    c
  37. Two offspring cells are most likely to inherit which one of the following from the parent cell? 
    a) a change in a nucleotide in mRNA
    b) a change in a nucleotide in tRNA
    c) a change in a nucleotide in rRNA
    d) a change in a nucleotide in DNA
    e) a change in a protein
    d
  38. Which of the following is not a method of horizontal gene transfer?
    a) binary fission
    b) conjugation
    c) integration of a transposon
    d) transduction
    e) transformation
    a

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