Chapter 8 Microbial Genetics

Microbiology An Introduction, 11e (Tortora/Case)Chapter 8 Microbial Genetics8. 1 Multiple ChoiceQuestions1) A cistron is best defined as A) a segment of deoxyribonucleic acid. B) three nucleotides that code for an amino acid. C) a ecological succession of nucleotides in deoxyribonucleic acid that codes for a structural product. D) a sequence of nucleotides in RNA that codes for a functional product. E) a transcribed unit of deoxyribonucleic acid. assist C acquirement anamnesis2) Which of the following pairs is incongruous? A) desoxyribonucleic acid polymerase makes a molecule of DNA from a DNA template B) RNA polymerase makes a molecule of RNA from an RNA template C) DNA ligase joins segments of DNA D) transposase insertion of DNA segments into DNA E) DNA gyrase coils and twists DNA process B cleverness Recall3) Which of the following statements is fictitious? A) DNA polymerase joins nucleotides in adept style only. B) The leading strand of DNA is made continuousl y. C) The lagging strand of DNA is started by an RNA primer. D) DNA replication proceeds in one heraldic bearing around the bacteriuml chromosome. E) Multiple replication forks atomic number 18 possible on a bacterial chromosome. serve up D accomplishment intellectual4) DNA is constructed of A) a single strand of nucleotides with internal hydrogen bonding. B) ii complementary strands of nucleotides bonded AC and GT. C) two strands of nucleotides running antiparallel. D) two strands of identical nucleotides with hydrogen bonds amidst them. E) None of the resolves is correct. adjudicate C aptitude Understanding5) Which of the following is NOT a product of transcription? A) a new strand of DNA B) rRNA C) transfer RNA D) mRNA E) None of the answers are correct all of these are products of transcription. solvent A Skill Understanding6) Which of the following statements about bacteriocins is FALSE? A) The genes coding for them are on plasmids. B) They cause food-poisoning symp toms. C) Nisin is a bacteriocin used as a food preservative. D) They crumb be used to identify certain bacteria. E) Bacteriocins kill bacteria. resoluteness B Skill Understanding lick 8. 17) In Figure 8. 1, which colonies are streptomycin-resistant and leucine-requiring? A) 1, 2, 3, and 9 B) 3 and 9 C) 4, 6, and 8 D) 4 and 8 E) 5 and 6 Answer D Skill Analysis control board 8. 1 Culture 1 F+, leucine+, histidine+ Culture 2 F-, leucine-, histidine-8) In Table 8. 1, what ordain be the response of conjugation between cultures 1 and 2? A) 1 will remain the alike(p) 2 will become F+, leucine-, histidine- B) 1 will become F-, leu+, his+ will become F+, leu-, his- C) 1 will become F-, leu-, his- 2 will remain the same D) 1 will remain the same 2 will become F+, leu+, his+ E) 1 will remain the same 2 will become F+ and recombination may fall Answer A Skill Analysis9) In Table 8. 1, if culture 1 mutates to Hfr, what will be the result of conjugation between the two cultures? A) They w ill twain remain the same. B) 1 will become F+, leu+, his+ 2 will become F+, leu+, his+ C) 1 will remain the same recombination will occur in 2 D) 1 will become F-, leu+, his+ 2 will become Hfr, leu+, his+ E) The answer butt endnot be placed based on the in fundamental law provided. Answer C Skill Analysis10) An enzyme produced in response to the presence of a substrate is called a(n) A) inducible enzyme. B) repressible enzyme. C) restriction enzyme. D) operator. E) promoter. Answer A Skill Recall11) When glucose is high, cAMP is _____ crest _____ take the lac operator, and RNA polymerase _____ bind the lac promoter. A) high does does B) low does not does not C) high does not does D) low does not does E) None of the answers is correct. Answer B Skill Understanding12) Transformation is the transfer of DNA from a donor to a recipient cell A) by a bacteriophage. B) as naked DNA in solution. C) by cell-to-cell contact. D) by crossing over. E) by sexual reproduction. Answer B Skill Recall13) Genetic change in bacteria can be brought about by A) mutation. B) conjugation. C) transduction. D) transformation. E) All of the answers are correct. Answer E Skill Understanding14) Which of the following statements regarding a bacterium that is R+ is FALSE? 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. Answer D Skill Understanding15) The initial effect of ionizing radiation on a cell is that it causes A) DNA to break. B) bonding between adjacent thymines. C) base substitutions. D) the formation of highly reactive ions. E) the cells to get hot. Answer D Skill Recall16) According to the operon model, for the price reduction of an inducible enzyme to occur, the A) end-product moldiness 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. Answer C Skill Understanding17) Synthesis of a repressible enzyme is stopped by the A) allosteric transition.B) substrate binding to the repressor. C) corepressor binding to the operator. D) corepressor-repressor complex binding to the operator. E) end product binding to the promoter. Answer D Skill Understanding Figure 8. 2REPLICATION FORK18) In Figure 8. 2, if base 4 is thymine, what is base 4? A) adenine B) thymine C) cytosine D) guanine E) uracil Answer A Skill Analysis19) In Figure 8. 2, if base 4 is thymine, what is base 11? A) adenine B) thymine C) cytosine D) guanine E) uracil Answer B Skill Analysis20) In Figure 8. 2, base 2 is attached to A) ribose. B) phosphate. C) deoxyribose. D) thymine. E) The answer cannot be jogd based on the information provided. Answer C Skill Recall21) The damage caused by ultraviolet radiation is A) never repaired. B) repaired during transcription. C) repaired during translation. D) cut out and replaced. E) r epaired by DNA replication. Answer D Skill Recall Table 8. 2 Codon on mRNA and corresponding amino acid UUA leucine UAA nonsense GCA alanine AAU sparagine AAG lysine UGC cysteine GUU valine UCG, UCU serine 22) Refer to Table 8. 2. If the sequence of amino acids encoded by a strand of DNA is serine-alanine-lysine-leucine, what is the order of bases in the sense strand of DNA? A) 3 UGUGCAAAGUUA B) 3 AGACGTTTCAAT C) 3 TCTCGTTTGTTA D) 5 TGTGCTTTCTTA E) 5 AGAGCTTTGAAT Answer B Skill Analysis23) Refer to Table 8. 2. If the sequence of amino acids encoded by a strand of DNA is serine-alanine-lysine-leucine, the coding for the antisense strand of DNA is A) 5 ACAGTTTCAAT. B) 5 TCTGCAAAGTTA. C) 3 UGUGCAAAGUUA. D) 3 UCUCGAAAGUUA. E) 3 TCACGUUUCAAU. Answer B Skill Analysis24) Refer to Table 8. 2 The anticodon for valine is A) GUU. B) CUU. C) CTT. D) CAA. E) GTA. Answer D Skill Understanding25) Refer to Table 8. 2. What is the sequence of amino acids encoded by the following sequence of bases in a strand of DNA? 3 ATTACGCTTTGC A) leucine-arginine-lysine-alanine B) asparagine-arginine-lysine-alanine C) asparagine-cysteine-valine-serine D) Translation would stop at the first codon. E) The answer cannot be determined based on the information provided. Answer D Skill Analysis26) Refer to Table 8. 2. If a frameshift mutation occurred in the sequence of bases shown below, what would be the sequence of amino acids coded for? ATTACGCTTTGC A) leucine-arginine-lysine-alanine B) asparagine-arginine-lysine-alanine C) asparagine-cysteine-valine-serine D) Translation would stop at the first codon. E) The answer cannot be determined based on the information provided. Answer E Skill Understanding 27) In Figure 8. 3, if compound C reacts with the allosteric site of enzyme A, this would exemplify A) a mutation. B) repression. C) feedback inhibition. D) competitive inhibition. E) transcription. Answer C Skill Understanding28) In Figure 8. 3, if enzyme A is a repressible enzyme, compound C would A) always be in excess. B) bind to the enzyme. C) bind to the corepressor. D) bind to RNA polymerase. E) bind to gene a. Answer C Skill Understanding29) In Figure 8. 3, if enzyme A is an inducible enzyme, A) compound C would bind to the repressor. B) compound A would bind to the repressor. C) compound B would bind to enzyme A. D) compound A would react with enzyme B. E) compound C would react with gene a. Answer B Skill Understanding30) Conjugation differs from reproduction because conjugation A) 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. Answer C Skill Understanding31) 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 military personnel cell. The DNA synthesized would be most similar to A) human DNA. B) T. aquaticus DNA. C) a mixture of hu man and T. aquaticus DNA. D) human RNA. E) T. aquaticus RNA. Answer A Skill Understanding Table 8. 3 Amino Acids Encoded by the Human p53 Gene pic32) base on the information in Table 8. 3, prostate cancer is probably the result of which kind of mutation? A) analog B) frameshift C) missense D) nonsense E) None of the answers is correct. Answer D Skill Analysis Figure 8. 433) In Figure 8. 4, the antibiotic chloramphenicol binds the 50S ribosome as shown. From this information you can conclude that chloramphenicol A) prevents transcription in eukaryotes. B) prevents translation in eukaryotes. C) prevents transcription in prokaryotes. D) prevents translation in prokaryotes. E) prevents mRNA-ribosome binding. Answer D Skill Analysis34) The mechanism by which the presence of glucose inhibits the arabinose operon is A) catabolite repression. B) translation. C) DNA polymerase. D) repression. E) induction. Answer A Skill Recall35) The mechanism by which the presence of arabinose controls th e arabinose operon is A) catabolite repression. B) translation. C) DNA polymerase. D) repression. E) induction. Answer E Skill Recall36) 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 protein B) the secondary structure of the protein C) the tertiary structure of the protein D) the quaternary structure of the protein E) The answer cannot be determined based on the information provided. Answer A Skill Understanding37) An enzyme that makes covalent bonds between nucleotide sequences in DNA is A) RNA polymerase. B) DNA ligase C) DNA helicase. D) transposase. E) DNA polymerase. Answer B Skill Recall38) An enzyme that copies DNA to make a molecule of RNA is A) RNA polymerase. B) DNA ligase. C) DNA helicase. D) transposase. E) DNA polymerase. Answer A Skill Recall39) An enzyme that catalyzes the cutting and resealing of DNA, and is translated from insertion sequences, is A) RNA po lymerase. B) DNA ligase.C) DNA helicase. D) transposase. E) DNA polymerase. Answer D Skill Recall40) Repair of modify DNA might be viewed as a race between an endonuclease and A) DNA ligase. B) DNA polymerase. C) helicase. D) methylase. E) primase. Answer D Skill Understanding41) 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 delinquent to a mistake by A) a chemical mutagen. B) DNA polymerase. C) photolyases. D) snRNPs. E) UV radiation. Answer D Skill Understanding Figure 8. 542) In Figure 8. 5, which model of the lac operon correctly shows RNA polymerase, lactose, and repressor protein when the structural genes are being transcribed? A) a B) b C) c D) d E) e Answer D Skill Analysis43) The miRNAs in a cell A) are found in prokaryotic cells. B) are a part of the prokaryotic ribosome. C) are a part of the eukaryotic ribosome. D) allow different cells to prod uce different proteins. E) are responsible for inducing operons. Answer D Skill Recall44) Assume the two E. coli strains shown below are allowed to conjugate. Hfrpro+, arg+, his+, lys+, met+, ampicillin-sensitiveFpro-, arg-, his-, lys-, met-, ampicillin-resistant What supplements would you add to glucose minimal salts agar to select for a recombinant cell that is lys+, arg+, amp-resistant? A) ampicillin, lysine, arginine B) lysine, arginine C) ampicillin, proline, histidine, methionine D) proline, histidine, methionine E) ampicillin, prolein, histidine, lysine Answer C Skill Analysis45) Protein synthesis in eukaryotes is similar to the process in prokaryotes in that both eukaryotes and prokaryotes A) have exons. B) have introns. C) require snRNPS. D) use methionine as the start amino acid. E) use codons to determine polypeptide sequences. Answer E Skill Understanding 8. 2True/FalseQuestions1) Recombination will always alter a cells genotype. Answer TRUE Skill Understanding2) Open-re ading frames are segments of DNA in which both start and stop codons are found. Answer TRUE Skill Understanding3) Bacteria typically contain multiple chromosomes. Answer FALSE Skill Recall4) Mutations that are harmful to cells occur more frequently than those that benefit cells. Answer TRUE Skill Recall5) The miRNAs in a cell inhibit protein synthesis by forming complementary bonds with rRNA. Answer FALSE Skill Recall6) Some organisms may contain multiple genomes. Answer FALSE Skill Recall7) Both base substitution and frameshift mutations can result in the formation of premature stop codons. Answer TRUE Skill Recall8) In the Ames test, any colonies that form on the control should be the result of spontaneous mutations. Answer TRUE Skill Recall9) Transposition results in the formation of base substitution mutations in a cells DNA. Answer FALSE Skill Recall 10) Cell-to-cell contact is required for transduction to occur. Answer FALSE Skill Understanding 8. 3Essay Questions1) What is th e survival value of the semiconservative replication of DNA?2) Scientists are concerned that bacteria will be resistant to all antibiotics within the next decade. Using your knowledge of genetics, describe how bacterial populations can develop drug resistance in such a short time frame.3) Explain why the following statement is false Sexual reproduction is the only mechanism for genetic change.4) why must the cultures used in the Ames test be auxotrophic? Explain the necessity of using a strain that is mutated in this experiment.5) What is the survival value of the degeneracy of the genetic code?