Micro Chapter 14

25 July 2022
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question
15. Regulation of gene expression serves to do all of the following except A. conserve energy and raw materials. B. maintain balance between the amounts of various cell proteins. C. adjust the activity of existing proteins in the cell. D. adapt to long-term environmental change.
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C. adjust the activity of existing proteins in the cell.
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16. In two component regulatory systems, the response regulator typically receives a ____________ from the sensor kinase when it has been activated. A. pyruvate group B. phosphoryl group C. acetyl group D. methyl group
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B. phosphoryl group
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17. While standard two-component regulatory systems typically act to control gene transcription, phosphorelay systems can act either to control gene transcription or to control A. translation. B. protein activity. C. DNA replication. D. all of the choices.
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B. protein activity.
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18. The sensor kinase for the OmpF: OmpC two-component regulatory system is A. the OmpK protein. B. the EnvZ protein. C. the MicF RNA. D. none of the choices.
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B. the EnvZ protein.
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19. The E. coli lac operon has ________ operator sequences. A. one B. two C. three D. four
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C. three
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20. So-called two-component regulatory systems A. include a sensor kinase and a response regulator. B. play a key role in regulating sporulation in Bacillus. C. play a key role in regulating the OmpF and OmpC porin proteins in E. coli. D. all of the choices
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D. all of the choices
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21. If Escherichia coli is cultured in broth containing both glucose and lactose, it A. uses glucose preferentially until the supply is exhausted, then uses lactose. B. uses lactose preferentially until the supply is exhausted, then uses glucose. C. uses glucose and lactose simultaneously. D. uses only the glucose (it cannot use lactose as a source of carbon).
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A. uses glucose preferentially until the supply is exhausted, then uses lactose.
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22. __________ activate repressor proteins thereby decreasing the synthesis of certain enzymes. A. Inducers B. Corepressors C. Effectors D. Modulators
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B. Corepressors
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23. __________ alter repressor proteins thereby increasing the rate of transcription initiation. A. Inducers B. Corepressors C. Effectors D. Modulators
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A. Inducers
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24. ______________ is used to control transcription of some anabolic pathways involved in amino acid biosynthesis. A. Attenuation B. Catabolite repression C. Induction D. All of the choices
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A. Attenuation
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25. When a repressor binds to the operator site on the DNA it normally A. inhibits the initiation of transcription. B. reduces the rate of transcription. C. terminates transcription that has already been initiated. D. has no effect on transcription.
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A. inhibits the initiation of transcription.
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26. Enzymes that are expressed at a constant level all the time are said to be: A. inducible. B. repressible. C. constitutive. D. attenuated.
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C. constitutive.
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27. Which of the following is not a regulatory mechanism used to control the tryptophan operon in Escherichia coli? A. repression B. catabolite repression C. attenuation D. all of the choices
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B. catabolite repression
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28. Which of the following is not a regulatory mechanism used to control the lactose operon in Escherichia coli? A. induction B. catabolite repression C. attenuation D. all of the choices
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C. attenuation
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29. The site on the DNA to which a repressor protein binds is the __________. A. operon B. operator C. promoter D. regulator
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B. operator
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30. When bound to the DNA, the repressor protein usually prevents attachment of the RNA polymerase to the __________. A. operon B. operator C. promoter D. regulator
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C. promoter
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31. The __________ is a factor-independent termination site found in the leader region of certain operons, which, under the influence of ribosome behavior, controls the continued transcription of that operon. A. modulator B. operator C. attenuator D. terminator
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C. attenuator
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32. What is the key factor determining whether or not attenuation will occur when transcription of the E. coli trp operon has been initiated? A. The activity level of adenyl cyclase. B. The trp operon repressor. C. The level of tryptophan in the environment. D. The level of trp-tRNA that is charged with tryptophan.
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D. The level of trp-tRNA that is charged with tryptophan.
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33. With the E. coli trp operon where both repression and attenuation occur, the extent of regulation achieved by repression is _____________ the extent of regulation achieved by attenuation. A. the same as B. less than C. greater than D. repression is not used in the regulation of the E. coli trp operon
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C. greater than
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34. The terminator versus anti-terminator function of the T box-based riboswitch used by Gram-positive bacteria to regulate amino acid-related genes is determined by A. the binding of the appropriate uncharged tRNA. B. the rate of leader peptide synthesis. C. the binding of the T box binding protein. D. the utilization of the appropriate sigma factor by RNA polymerase.
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A. the binding of the appropriate uncharged tRNA.
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35. Most E. coli antisense RNAs work with a protein called ______ to regulate their target mRNAs. A. CAP B. MicF C. Hfq D. none of the choices
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C. Hfq
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36. Riboswitches that can block the initiation of translation because of a conformational change that occurs in the leader sequence of an mRNA when the appropriate regulatory effector binds the mRNA achieve that blockage of translation initiation by the occlusion of A. the promoter. B. the attenuator. C. the Shine-Delgarno sequence. D. the AUG start codon.
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C. the Shine-Delgarno sequence.
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37. Posttranslational regulation occurs after a protein has been synthesized, and can occur by A. allosteric regulation. B. feedback inhibition. C. covalent modification. D. allosteric regulation and covalent modification are both means of regulation after translation is complete.
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D. allosteric regulation and covalent modification are both means of regulation after translation is complete.
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38. What term describes a set of genes that is controlled by a common regulatory protein? A. codon B. regulon C. transcription D. operon
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B. regulon
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39. In some circumstances, when two different carbon sources are available, growth will occur first using one carbon source, then after a short lag period, growth will resume using the second carbon source. This process is called __________ growth. A. biphasic B. bimorphic C. diauxic D. dimorphic
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C. diauxic
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40. The activity of adenyl cyclase is influenced by A. the phosphotransferase system. B. the presence of lactose in the environment. C. homoserine lactones. D. none of the choices.
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A. the phosphotransferase system.
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41. An operon network that is under the control of a common regulatory protein while each operon is still also under the control of its own unique regulatory protein is most specifically referred to as a A. regulon. B. webulon. C. modulon. D. complexon.
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C. modulon.
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42. The standard or housekeeping sigma factor used most often by E. coli RNA polymerase under normal growth conditions is called sigma ___. A. 70 B. 32 C. S D. E
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A. 70
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43. Acylhomoserine lactones used in quorum sensing regulate their own synthesis by a(n) ____________ system. A. riboswitch B. antisense C. catabolite repression D. autoinduction
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D. autoinduction
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44. During sporulation in Bacillus subtilis, the response regulator that positively controls many genes needed for sporulation and negatively controls genes not needed during sporulation is A. SpoOB. B. SpoOA. C. SpoOF. D. SpoOC.
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B. SpoOA.
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45. During the early stages of sporulation in Bacillus subtilis, ________ is active in the forespore and ________ is active in the mother cell. A. E; F B. K; F C. F; K D. F; E
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D. F; E
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46. During sporulation in Bacillus subtilis, inactive precursor forms of new sigma factors are activated at the appropriate time by A. proteolysis. B. phosphorylation. C. RNA binding. D. chaperone re-folding.
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A. proteolysis.
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47. The sensing of starvation that leads to sporulation in Bacillus subtilis is accomplished by a(n) A. small RNA. B. sensor kinase. C. response regulator. D. quorum regulatory effector.
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B. sensor kinase.
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48. Cell-to-cell communication by quorum sensing has been shown to be important in the regulation of genes needed for A. virulence. B. biofilm production. C. plasmid transfer. D. all of the choices.
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D. all of the choices.
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49. When the Catabolite Activator Protein binds to its binding site in DNA, it A. displaces repressors. B. bends the DNA. C. promotes the assembly of other transcription factors at the promoter. D. eliminates the need for a sigma factor on the part of RNA polymerase.
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B. bends the DNA.