2. The promoter (P) is the start site of transcription through the binding of RNA polymerase before actual mRNA production. Mutated promoters (P) cannot bind RNA polymerase, so no mRNA is made. In the table below, make predictions about the expression of ß-galactosidase and permease for different partial diploid (F') genotypes. Do this to mark where there is no E. coli growth on two different types of media - one without lactose, and one with. Use a - enzyme produced, and a + to mark where the enzyme is made. The first genotype has all wild-type alleles, and has b- filled in as an example. Genotype I+P+O+Z+Y+ I+P+OcZ+Y- I-P*O*Z*Y*+ I+P+O+Z-Y/IPO*Z*Y* IP OCZ+Y/IPO+Z-Y* ISP+O+Z+Y/I+P+O+*Z-Y* Lactose absent B-galactosidase + Permease + Lactose present B-galactosidase Permease

2. The promoter (P) is the start site of transcription through the binding of RNA polymerase before actual mRNA production. Mutated promoters (P) cannot bind RNA polymerase, so no mRNA is made. In the table below, make predictions about the expression of ß-galactosidase and permease for different partial diploid (F') genotypes. Do this to mark where there is no E. coli growth on two different types of media - one without lactose, and one with. Use a - enzyme produced, and a + to mark where the enzyme is made. The first genotype has all wild-type alleles, and has b- filled in as an example. Genotype I+P+O+Z+Y+ I+P+OcZ+Y- I-POZY+ I+P+O+Z-Y/IPOZY* IP OCZ+Y/IPO+Z-Y* ISP+O+Z+Y/I+P+O+Z-Y Lactose absent B-galactosidase + Permease + Lactose present B-galactosidase Permease

Biology: The Dynamic Science (MindTap Course List)

4th Edition

ISBN:9781305389892

Author:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Publisher:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Chapter16: Regulation Of Gene Expression

Section: Chapter Questions

Problem 2TYK: For the E. coli lac operon, when lactose is present: a. and glucose is absent, cAMP binds and...

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10. Modify the diagrams below to reflect the activation and repression of lac operon. Use arrows, lines, X's, etc. to illustrate control of gene expression.S a. Activation lactose lactose CAP lac I repressor allolactose b. Repression CAP allolactose lac I repressor CAMP с CAMP с promoter operator +1 RNA Pol +1 RNA Pol promoter operator lac Z lac Z lac Y lac Y lac A lac A DNA DNA
12a. In what condition is the LacZ gene transcribed? ANSWER (in one sentence) 12b. Fill in the following table about the Lac operon (LacZ gene) Environmental Condition + Glucose and + Lactose Glucose and + Lactose - Glucose and - Lactose + Glucose and - Lactose Q 2 Body" W #3 E D Which proteins bind to the LacZ promoter? ANSWER ANSWER ANSWER ANSWER $ 4 A R F B % 5 I T MacBook Pro A U 6 G Y & 7 H Is LacZ transcribed? (Yes or No) ANSWER ANSWER ANSWER ANSWER |||| U 8 K
The trp operon is: **(for additional information review the CogBooks Module, answer explained on CogBooks): In the absence of tryptophan, the trp repressor dissociates from the operator, and RNA synthesis proceeds. promoter operator trpE| trpD trpC trpB trpA RNA polymerase repressor When tryptophan is present, the trp repressor binds the operator, and RNA synthesis is blocked. promoter operator trpE trpD trpC trpB trpA RNA polymerase; repressor tryptophan Both negative inducible and positive repressible Positive inducible Negative Repressible O Negative inducible
that best fits the phrase below (1-20) Cis-acting B Post-transcriptional modification Post-translational modification Reactive (R) group Trans-acting C Operon Nuclear localizationsignal Double-stranded RIA Shine-Dalgarno sequence Kozak sequence E site on ribosome Ps p riboeE8R3) A site on ribosome Constitutive F Allosteric transition Inducer ll ol g Repressor T G H. Nonsense codon Frameshift mutation W Chaperones Found upstream of AUG codons in bacteria, this binds the 3' end of the 16S rRNA of the 30S ribosomal subunit Addition of chemical groups to amino acids in a polypeptide Hidigel elnw eesel Poly (A) polymerase enzyme uses ATP as substrate to add a string of A nucleotides on to the 3'-OH of MRNA Jeiheg 1ot eninoaso uoy nielgxe 10 anoitamusas Tuoy elsta otehgo1qqs eedW 4 Is produced when both strands of DNA encoding a gene are transcribed simultaneously A class of proteins that arrest incorrectly or incompletely folded proteins 6. Occurs when allolactose binds Lacl protein causing…
O The lac operon in E.coli encodes enzymes necessary for the breakdown of lactose. For each enzyme (lac Z and lac Y), indicate with a + or-whether or not it is made when there is no lactose or when there is lactose. B-galactosidase (lac Z) No Lactose Permease (lac Y) Lactose Lactose No Lactose Genotype PP0 Z Y/I P*O*Z•Y* I'POCZ Y*/I P* O©Z*Y° P O Z'Y/I P'OʻZ'Y* PP O ZY*/IP*O*Z*Y* IP OCZ Y /I P*O*Z•Y* IPO ZY*/I* P*O©Z*Y• I'PO*Z Y*/IP'O*Z*Y°
1) A. What is the difference between a repressible vs, an inducible operon? B. Using diagrams and words, describe how the Lac Operon is regulated by different levels of lactose and glucose. Be sure to show what’s happening at the molecular level, including the roles of lactose, glucose the repressor protein, cAMP and CAP.
1. Complete the following table based on your lac operon simulations. Absence of lactose Presence of lactose B-galactosidase permease B-galactosidase permease I*P*O*Z*Y* Mututed ISP+O*ZY* I'P*O°Z*Y* I*P*O°ZY
. a. How many ribosomes are required (at a minimum)for the translation of trpE and trpC from a singletranscript of the trp operon?b. How would you expect deletion of the two tryptophan codons in the RNA leader to affect theexpression of the trpE and trpC genes?
High levels of glucose in the environment result in low levels of transcription of the lac operon. The reason for this is O glucose binds to the Lac Repressor to cause it to bind to the operator site (lac O) glucose lowers the levels of CAMP, which is necessary to activate the CAP protein O giucose raises the levels of CAMP, which binds to the CAP protein to cause transcription repression O glucose prevents lactose from binding to the Lac Repressor O glucose lowers the levels of the CAP protein, which is necessary to stimulate transcription of the lac operon
To characterize the promoter of the gadA operon you made a series of deletion mutants removing pieces of the promoter to see what would happen. The results are found below: gad promoter gada gadX gadz 450 +1 lacz activity transcription start site pH 2.0 pH 7.0 A gad promoter beta-galactosidase (lacZ) +++ 450 gad promoter beta galactosidase (lacZ) +++ +++ 300 +1 gad promoter beta galactosidase (lacZ) 150 D gad beta galactosidase (lacz) -450 150 E gad promoter beta-galactosidase (lacZ) -450 -300 Based on these results, what can you conclude about the gad promoter? O a. The promoter is only regulated by repression Ob. The promoter is regulated by a mix of activation and repression O c. The promoter is only regulated by activation O d. The promoter has multiple operators and multiple enhancers
Indicate whether each of the following statements about the lac operon are true or false: Bacteria with a lac phenotype are unable to use lactose because of some defect in expressing the genes A constitutive Lac+ phenotype could mean either that the production of repressor is defective or that the operator sequence is defective The lacl gene is next to, but is not part of, the lac 1. TRUE operon 2. FALSE Bacteria with a lac* phenotype cannot grow on media containing lactose as the only sugar The structural genes of the lac operon are each transcribed as a separate MRNA Expression of the Lac Repressor from the lacl promoter is regulated by lactose
2. The lac operon controls the inducible expression of genes involved in lactose utilization. Several naturally occurring mutations have been discovered that affect how the lac operon operates. Consider the following mutations: I-= a mutation in the repressor protein that cannot bind the operator Is = a mutation in the repressor protein that cannot be removed from the operator Oc= a mutation in the operator that cannot bind the repressor Detail the functionality of the lac operon with following genotypes and cellular conditions (Note if there is no superscript, there is no mutation) Genotype I, O I, OC IS, O I, O Is, Oc Lactose present No No Yes Yes No Repressed (yes/no) N VAS ves NO Constitutive (yes/no) NO NO YES Yes NO Inducible (yes/no) Yes yes NO NO YUS