OIOIOITest Bank forChapter 16: Control of Gene Expression in BacteriaMultiple-Choice Questions31. The trp operon is known to operate by both negative repressible regulation of operator and attenuation. Which of the following does NOT support the reason as to why dual control exists to regulate the operon?Short-Answer QuestionsTest Bank forChapter 16: Control of Gene Expression in BacteriaMultiple-Choice Questions1. Which of the following statement about regulation of gene expression is correct?a. An inducible gene is transcribed when a specific substance is absent. b. A gene is any DNA sequence that is transcribed into an mRNA molecule only. c. All genes are transcribed at all times as long as they have a functional promoter.d. The regulation of gene expression is the same in both eukaryotes and prokaryotes.e. The regulation of gene expression is critical for the control of life processes in all organisms.Answer: eSection: 16.1Comprehension 2. Which of the following generally get transcribed constitutively?a. Regulatory geneb. Structural genec. Operator elementd. Promoter elemente. OperonAnswer: bSection: 16.1Comprehension 3. Which of the following types of eukaryotic gene regulation is at the level of DNA?a. Alternation of chromatin structureb. mRNA processingc. RNA interferenced. mRNA stabilitye. Post-translational modificationAnswer: aSection: 16.1Comprehension 4. Which of the following DNA binding motifs are composed of three alpha helices?a. Zinc-fingerb. Leucine-zipperc. Homeodomaind. Helix-turn-helixe. Helix-loop-helixAnswer: cSection: 16.1Comprehension 5. Proteins with DNA binding motifs predominantly bind to the ____________ of DNA.a. major groovesb. minor groovesc. paired nitrogenous basesd. phosphate groupse. deoxyribose sugarAnswer: aSection: 16.1Comprehension 6. Which of the following statements about DNA binding protein is NOT true?a. Specific amino acids within the motif form hydrogen bonds with DNA.b. These proteins can affect the expression of a gene.c. Most DNA binding proteins bind dynamically.d. Some of these proteins incorporate metal ion such as zinc.e. Once bound, most of DNA binding proteins remain on DNA permanently.Answer: eSection: 16.1Comprehension Question7. Which of the following statements about gene regulation concerning operon is INCORRECT?a. A repressible gene is controlled by a regulatory protein that inhibits transcription. b. For a gene under negative repressible control, a small molecule is required to prevent the gene's repressor from binding to DNA. c. For a gene under positive repressible control, the normal state is transcription of a gene, stimulated by a transcriptional activator. d. A regulator gene has its own promoter and is transcribed into an independent mRNA.e. Presence of operon where genes of related functions are clustered is common in bacteria, but not in eukaryotes.Answer: bSection: 16.2Comprehension8. When binding of the inducer to the repressor causes a conformational change, which then prevents the repressor from binding to DNA, the repressor is called a(n) __________ protein.a. coactivatorb. allostericc. structurald. operatinge. responsiveAnswer: bSection: 16.2Comprehension 9. The________ is a type of regulator protein that binds to a region of DNA in the promoter of agene called the operator and prevents transcription from taking place. a. inducerb. repressorc. activatord. inactivatore. terminatorAnswer: bSection: 16.2Comprehension 10. An example of a gene product encoded by a regulatory gene isa. beta-galactosidase enzyme.b. allolactose.c. repressor protein.d. an operator.e. a terminator.Answer: cSection: 16.2Comprehension11. E. coli lac operon control by CAP isa. negative inducible. b. negative repressible.c. positive inducible.d. positive repressible.e. regulated by riboswitches.Answer: cSection: 16.2Application 12. An operon is controlled by a repressor. When the repressor binds to a small molecule, it bindsto DNA near the operon. The operon is constitutively expressed if a mutation prevents the repressor from binding to the small molecule. The type of control illustrated isa. negative inducible. b. negative repressible.c. positive inducible.d. positive repressible.e. catabolite repression.Answer: bSection: 16.2Comprehension 13. An operon is controlled by a repressor. When the repressor binds to a small molecule, it is released from binding to DNA near the operon. The operon is never expressed if a mutation prevents the repressor from binding to the small molecule. The type of control illustrated isa. negative inducible.b. negative repressible.c. positive inducible.d. positive repressible.e. attenuation.Answer: aSection: 16.2Comprehension 14. What is the function of allolactose in regulation of the lac operon?a. Inducerb. Repressorc. Activatord. Promotere. Regulatory proteinAnswer: aSection: 16.2Comprehension 15. What is the function of cAMP in regulation of the lac operon?a. It activates a repressor protein.b. It activates an activator protein.c. It inactivates a repressor protein.d. It inactivates an activator protein.e. It causes attenuation.Answer: bSection: 16.2Comprehension 16. In the absence of tryptophan, what happens to the genes within the trp operon?a. The regulator without tryptophan-binding prevents the genes from being transcribed.b. The regulator falls off the operator and structural genes get transcribed.c. Lack of tryptophan increases the level of cAMP high, which leads to activation of CAP protein and gene expression.d. The active repressor binds to the operator and genes do not get transcribed.e. The active activator binds to the operator and transcription of structural gene takes place. Answer: bSection: 16.2Application 17. When a structural gene is under positive inducible control, what would be the result of a mutation that eliminates the activator protein? a. The structural gene to be constitutively expressed due to the lack of inducible control. b. The transcription of structural gene will not be affected, as an activator is not required.c. The mutation will lead to activation of a repressor upon the lack of an activator protein, which will block transcription.d. d. As the transcription will require an activator protein, the transcription will be turned off.e. e. More cAMP will be produced in a cell to compensate for the lack of an activator protein.Answer: dSection: 16.2Application 18. When a structural gene is under negative inducible control, what would be the result of a mutation