Please help me with 34-51 it\'s molecular biology 34. In E. coli cells growing a
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Question
Please help me with 34-51 it's molecular biology
34. In E. coli cells growing at 37 degrees Celsius, the sigma 32 gene is_________, this is an example of gene regulation at the ___________level.
A. transcribed but not translated/transcriptional
B. transcribed and translated but not processed/post-transcriptional
C. transcribed and translated but the protein is destroyed by proteases/post-translational
35. Sigma 32 helps RNAP bind and transcribe the promoters of heat shock proteins and heat-stable protease genes. Why E. coli needs these proteins when growing at 42 degrees Celsius?
A. To destroy heat-denatured proteins that cannot be salvaged by the chaperonins
B. To stabilize sigma 70, the typical GTF of bacteria
C. To refold proteins denatured at these conditions
D. For two of these reasons
E. For all these reasons
36. If Sigma 70 could bind the unusual -10 promoter element (i.e. 5CCCCATNT3) and not the normal -10 promoter element (i.e. 5TATAAAT3), which of the following genes would have been expressed?
A. Mostly the normal housekeeping genes
B. Mostly the heat-shock induced proteins
C. About equal amounts of normal house-keeping proteins and heat-shock proteins
Regulation by allostery only
37. The regulator merR regulates transcription of the bmr gene promoter as a repressor by ________. Only the best answer will be scored.
A. binding DNA and not altering the conformation of DNA
B. binding DNA and altering the conformation of the RNAP
C. binding mercury ions and altering the conformation of itself (MerR)
D. binding mercury ions and DNA and altering the conformation of DNA
38. Since merR does not affect RNAP or sigma, the regulation is through _________.
A. cooperative DNA binding
B. allosteric changes of merR but not RNAP
C. allosteric changes of promoter DNA but not merR
D. allosteric changes of merR and the promoter DNA
39. NtrC binding of the UAS of the glnA gene involves all the following except that it_________.
A. is somewhat similar to enhancer binding by eukaryotic activators
B. must involve DNA bending/looping for regulator-RNAP interactions
C. involves recruitment of RNAP/sigma54 and cooperative DNA binding by the three proteins
D. allosteric changes of the RNAP and the core promoter DNA (formation of the open complex)
Dual function regulators, signal integration and combinatorial control
40. A dual function regulator may activate and repress the expression of the same or different genes. Which of the following is a dual function regulator?
A. lac repressor and CRP
B. CRP and merR
C. MerR and araC
D. araC and NtrC
41. When E. coli grows in the absence of glucose (and lactose) but in the presence arabinose, all the following may take place in the araBAD operon promoter except______________.
A. araC binds arabinose, araC-arabinose complex bind certain operators and activate transcription
B. cAMP-CRP complex binds DNA and activates transcription of the araBAD operon C. araC binds certain operators and shut down the promoter
D. cAMP becomes available in the cell
42. Which of the following regulators (as per the information available in the textbook), is capable of combinatorial control?
A. NtrC and MerR
B. MerR and CRP
C. CRP and araC
D. lac repressor
E. CRP
Bacteriophage lambda life cycle: Many layers of regulations
43. _______ is a lysogen and ______ is a prophage.
A. A host bacterium that has a prophage integrated into its chromosome/ a bacteriophage genome that is integrated into a chromosome of a cell
B. A transcriptional regulator that favors lysogenic cycle/ a phage genome just injected into the cytoplasm of a cell
C. A temperate phage (capable of lysogenic infection)/ a newly assembled bacteriophage inside a host cell
44. The lifestyle of the temperate phage such as bacteriophage lambda (BPL) is somewhat similar to the lifestyle of the human __________.
A. adenovirus (HAV)
B. papilloma virus (HPV)
C. herpes simplex virus (HSV)
D. immunodeficiency virus (HIV)
45. Which of the following is/are lytic cycle of the bacteriophage lambda (BPL) infection?
A. The prophage DNA removed itself away from the chromosome of the lysogenic host, replicated phage DNA and produced many phages
B. The phage DNA replicated, new phages are produced and the host bacterium is killed
C. The phage DNA is integrated to bacterial genome, the host bacterium survived
D. Two of these
E. None of these
46. If the lambda repressor bound to all the six operators (OR1, OR2 and OR3; and OL1, OL2 and OL3) and the operator-bound lambda repressors interact with each other ___________.
A. the phage is having a lytic cycle
B. the phage is having a lysogenic cycle
C. all the promoters of the virus are shut down
D. the phage is having a lytic cycle and all the promoters are turned on
E. the phage is having a lysogenic cycle and all the promoters are turned of
47. If lambda repressor is bound to OR1 and OR2 but not OR3, all the following take place except _______.
A. the promoter PR is repressed
B. the promoter PRM is activated
C. lambda repressor mRNA are synthesized
D. cro mRNA and cro proteins are synthesized
48. When the phage DNA enters the host, host RNAP binds the BPL promoters PR and PL and produces_______.
A. Cro and CII mRNA from the PR promoter
B. CIII mRNA from the PL promoter
C. CI mRNA from PRM promoter
D. two of these
E. none of these
49. If CIII and CII proteins of BPL are made in the infected cell, _________
A. CIII protein would destroy CII protein and the virus would certainly choose the lytic cycle
B. CII protein would bind and activate the PRE promoter and transcribe CI mRNA
C. CII would bind and activate the PRM promoter and transcribe cro mRNA
D. CIII would bind/activate PL promoter and help transcribe CIII mRNA
50. Suppose a BPL injected its genome inside a E. coli cell, and the RNAP initially bound to remoter PR and made sufficient amounts of cro mRNA. Excess cro protein would cause all the following except_________ and the virus would choose the lytic cycle.
A. bind operator OR3
B. shut down the promoter PRM
C. activate the synthesis of CI mRNA
D. prevent the synthesis of lambda repressor (CI) mRNA
E. operators OR1, OR2, OL1 and OL2 remain unoccupied
51. If CII protein binds and activates the promoter PI, __________ mRNA (and protein) will be synthesized, and the protein will ____________.
A. int/ insert the phage genome inside the host chromosome via CSSR
B. xis/ remove the provirus genome from the host cell chromosome
C. int/ remove the provirus genome from the host chromosome
Explanation / Answer
43. _______ is a lysogen and ______ is a prophage.
Ans) Option C. A temperate phage (capable of lysogenic infection)/ a newly assembled bacteriophage inside a host cell.
34. In E. coli cells growing at 37 degrees Celsius, the sigma 32 gene is_________, this is an example of gene regulation at the ___________level.
Ans) Option A. transcribed but not translated/transcriptional.
45. Which of the following is/are lytic cycle of the bacteriophage lambda (BPL) infection?
Ans) D. Two of these
{A. The prophage DNA removed itself away from the chromosome of the lysogenic host, replicated phage DNA and produced many phages
B. The phage DNA replicated, new phages are produced and the host bacterium is killed.} These statesments are true.
46. If the lambda repressor bound to all the six operators (OR1, OR2 and OR3; and OL1, OL2 and OL3) and the operator-bound lambda repressors interact with each other ___________.
Ans) B. the phage is having a lysogenic cycle.
47. If lambda repressor is bound to OR1 and OR2 but not OR3, all the following take place except _______.
Ans) B. the promoter PRM is activated