Question

In: Biology

An E. coli merodiploid has the following genotype: lacI+ lacOc lacZ- lacY+ lacA-/ F’ lacI- lacO+...

An E. coli merodiploid has the following genotype:

lacI⁺ lacO^c lacZ^- lacY⁺ lacA^-/ F’ lacI^- lacO⁺ lacZ⁺ lacY^- lacA⁺

What is this strain’s phenotype in the absence (-) or presence (+) of IPTG?

A.

- IPTG: LacZ⁺ LacY^- LacA⁺ + IPTG: LacZ⁺ LacY⁺ LacA⁺

B.

- IPTG: LacZ^- LacY^- LacA^- + IPTG: LacZ⁺ LacY⁺ LacA⁺

C.

- IPTG: LacZ⁺ LacY^- LacA⁺ + IPTG: LacZ⁺ LacY⁺ LacA⁺

D.

- IPTG: LacZ^- LacY⁺ LacA^- + IPTG: LacZ⁺ LacY⁺ LacA⁺

E.

- IPTG: LacZ^- LacY⁺ LacA^- + IPTG: LacZ^- LacY⁺ LacA^-

Expert Solution

lac repressor inhibits the expression of lac operon by binding to the operator of the lac operon, lac repressor is inhibited by inducer so lac operon is expressed if inducer is present.

IPTG is an inducer of the lac operon.

the cell has two operons one in the chromosome and the other in the plasmid.

lacI+ lacOc lacZ- lacY+ lacA- this operon is in the chromosome, from this operon lac repressor encoded by the lac I gene is produced, so the cell will have functional lac repressor, and this operon has constitutive lac operator, lac repressor cannot bind to constitutive lac operator, so this lac operon is expressed always in the cell even if the inducer is absent. from this operon lac Y is expressed other two genes, lac Z and lac A are mutated.

lacI- lacO+ lacZ+ lacY- lacA+ this operon is present on the plasmid this operon is inhibited by the functional repressor produced from the operon in the chromosome, so this operon can be expressed only in the presence of inducer, if IPTG is present this lac operon is expressed.from this operon lac A and lac Z are produced if IPTG is present.

D.- IPTG: LacZ- LacY+ LacA- + IPTG: LacZ+ LacY+ LacA+

gladiator answered 2 years ago

An E. Coli strain has the following lac genotype: Lacl+ lacP+ lacOc lacZ- / lacl- lacP+...

An E. Coli strain has the following lac genotype: Lacl+ lacP+ lacOc lacZ- / lacl- lacP+ lacO + lacZ + If lactose is PRESENT, what would the level of Beta-galactose be? 1- High 2- Low

The E. coli LacZ will be used as a reporter gene and the expression of the...

The E. coli LacZ will be used as a reporter gene and the expression of the LacZ gene product will be detected by the enzymatic cleavage of the compound X-gal producing blue staining within the embryo. Why was an E. coli LacZ gene used as a reporter gene? Why is there a Drosophila weak basal promoter located on the P[lacZ] enhancer-trap element? The E. coli LacZ will be used as a reporter gene and the expression of the LacZ gene...

3. Describe a method to isolate E. coli mutants that do not transcribe lacZ?

For each E coli genotype and condition in the following table, choose which sets of functional...

For each E coli genotype and condition in the following table, choose which sets of functional proteins will or will not be produced. All grown in media with no/low glucose. IS indicates a super-repressor (it can’t bind to lactose/inducers). OC indicates a constitutive operon (no repressor can bind to this region of DNA). I- ; Z- ; Y-each indicate an allele that does not produce a functional protein. P- indicates a mutation in the promoter region such that RNA polymerase...

“Lactose repressor protein (LacI) utilizes an allosteric mechanism to regulate transcription in E. coli, and the...

“Lactose repressor protein (LacI) utilizes an allosteric mechanism to regulate transcription in E. coli, and the transition between inducer- and operator-bound states has been simulated by targeted molecular dynamics (TMD). The side chains of amino acids 149 and 193 interact and were predicted by TMD simulation to play a critical role in the early stages of the LacI conformational change. D149 contacts IPTG directly, and variations at this site provide the opportunity to dissect its role in inducer binding and...

1)A mutant E. coli was constructed containing a nonpolar null mutation in the lacZ gene. The...

1)A mutant E. coli was constructed containing a nonpolar null mutation in the lacZ gene. The null mutation resulted in a nonfunctional LacZ product. In the presence of lactose, would this mutant E. coli be induced to make Lac permease (LacY)? Why or why not? 2)What is the difference between a repressor and aporepressor?

I remember the professor telling the class LacZ and LacY both are not inducible. Maybe one...

I remember the professor telling the class LacZ and LacY both are not inducible. Maybe one of them is but not both. Please help explain. For each of the E. coli strains containing the lac operon alleles listed, indicate whether the strain is inducible, constitutive, or unable to express ?-galactosidase and permease. Provide an explanation for your prediction C. I+ O+ Z- Y+ / I? O^c Z+ Y?

Which of the following statements is TRUE? E. coli sigma factors all recognize one E. coli...

Which of the following statements is TRUE? E. coli sigma factors all recognize one E. coli gene Prokaryotic mRNAs contain sequences for sigma factor binding mRNA in both E. coli and humans are translated with the same translation machinery E. coli sigma factors all bind to the core RNA polymerase mRNA always contains the nucleotide sequence encoding just one protein

Can you please explain what the roles of LacY, LacZ, Operators, IPTG, and Lac Repressors in lactose...

Can you please explain what the roles of LacY, LacZ, Operators, IPTG, and Lac Repressors in lactose metabolism

Which genotype will allow the bacteria to make ß-galactosidase (lacZ) in the absence of lactose? (superscripts...

Which genotype will allow the bacteria to make ß-galactosidase (lacZ) in the absence of lactose? (superscripts don't work in this panopto quiz, so check the lecture slide itself) 1) O+Z+/F’O+Z+ 2) O+Z-/F’OCZ+ 3) O+Z+/F’OCZ- B) 1Which genotype will allow the bacteria to make ß-galactosidase (lacZ) in the absence of lactose? 1) I+O+Z+/F’I+O+Z+ 2)I-O+Z-/F’I+O+Z+ 3) I+O+Z-/F’I-O+Z+ 4) I-O+Z+/F’I-O+Z+