The map of the lac operon is:POZYThe promoter (P) region is the start site of transcription through the binding of the RNApolymerase molecule before actual MRNA production. Mutationally altered promoters (P') cannotbìnd the RNA polymerase molecule. Certain predictions can be made about the effect of Pmutations. Use your knowledge of the lactose system to complete the table below. Insert a "+"where enzyme is produced and a "-" where enzyme is not produced. Indicate whether the partialdiploid strain is lac* (able to grow on lactose-only medium) or lac( cannot grow in lactose medium).B-GalactosidasePermeasePhenotype(Lac orNumberGenotypeNo Lactose LactoseNo Lactose LactoseLac)P*O*Z*Y#Examplelac+I*p*O*z*Y*aIp*o+z*Y*I*p*oCz*YCI*p*o+z*Y

The lac operon is a catabolic operon and is expressed in the presence of the inducer lactose.

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Biochemistry

P*O*Z*Y# Example lac+ I*p*o+z*Y* FP*0*Z*Y* IP*o*z*Y* -P#O*Z¥Y* I*p*oCz*Y C I*p*o+z*Y

POZY# Example lac+ Ipo+zY FP0ZY* IPozY -P#OZ¥Y IpoCzY C Ipo+zY

Biology (MindTap Course List)

11th Edition

ISBN:9781337392938

Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg

Publisher:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg

Chapter14: Gene Regulation

Section: Chapter Questions

Problem 9TYU: A mutation that inactivates the repressor gene of the lac operon results in (a) the continuous...

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INTERPRET DATA Develop a simple hypothesis that would explain the behavior of each of the following types of mutants in E. coli. Mutant a: The map position of this mutation is in the trp operon. The mutant cells are constitutive; that is, they produce all the enzymes coded for by the trp operon, even if large amounts of tryptophan are present in the growth medium. Mutant b: The map position of this mutation is in the trp operon. The mutant cells do not produce any enzymes coded for by the trp operon under any conditions. Mutant c: The map position of this mutation is some distance from the trp operon. The mutant cells are constitutive; that is, they produce all the enzymes coded for by the trp operon, even if the growth medium contains large amounts of tryptophan.
A number of mutations affect the expression of the lac operon in E. coli. Consider each genotype below and complete the table using “+” to indicate that the gene is expressed, and “−” to indicate that gene is not expressed.
As diagrammed below, some amino acid biosynthetic operons have stem loop structures in the mRNA. These structures play a role in the regulation of the operon by which of the following mechanisms? Translation stop codon- Attenuator loop. mRNA 5' 3' DNA attenuator trpE O Catabolite repressor protein can bind and prevent the hairpins from forming thus allowing translation to occur. O The leader sequence shown contains codons for the amino acid. When these are low, the ribosome stalls, allowing a hairpin between the two middle regions to form so that the rest of the message can be translated. In the presence of large amounts of the amino acid, the hairpin will wind around the amino acid and prevent further translation. O A repressor protein made of that amino acid will bind to the region and prevent translation when large amounts of the amino acid are present. O The uridine-rich region has codons for that amino acid; when present, this region will be a terminator region. The hairpins allow…
Supply the words “off" or “on" in the blanks below: In an inducible operon, transcription is normally and must be turned In a repressible operon, transcription is normally and must be turned Briefly describe the overall function of the structural genes in the lac operon. Briefly describe the overall function of the structural genes in the trp operon. For the following descriptions of the bacterial lac operon, determine if lactose is present (P) or absent (A). The repressor is bound to the operator. The repressor is inactive. RNA polymerase transcribes the structural genes. Allolactose is bound to the repressor For the following descriptions of the bacterial trp operon, determine if tryptophan levels are high (H) or low (L). The repressor is bound to the operator. The repressor is inactive. RNA polymerase transcribes the structural genes. Tryptophan is bound to the repressor.
Lactose permease is encoded by the lacY gene of the lac operon.Suppose a mutation occurred at codon 64 that changed the normalglycine codon into a valine codon. The mutant lactose permease isunable to function. However, a second mutation, which changescodon 50 from an alanine codon to a threonine codon, is able torestore function. Is each of the following terms appropriate or inappropriate to describe this second mutation?A. ReversionB. Intragenic suppressorC. Intergenic suppressorD. Missense mutation
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
The diagram below represents the tryptophan operon with the trp leader mRNA transcript enlarged to represent the AUG translation start codon, two consecutive tryptophan amino acid codons (UGGUGG), and 4 regions (1, 2, 3, and 4) that base pair to form different hairpin-loop structures in the MRNA leader region. Suppose a mutant bacteria has region 4 of the trp operon attenuator region mutated so that it cannot base pair normally. Would the bacteria grow in the absence of the amino acid tryptophan? (hint: in order for bacteria to grow in absence of tryptophan it should be able to synthesize its own tryptophan) Lead&r region trpE trpD trpC trpB trpA DNA 5' 3' Transcription trp leader sequence MRNA UGGUGG 1 (tryptophan codons) AUG UUUUUU No There is insutficient information to answer the question. O Yes
The diagram below represents the tryptophan operon with the trp leader mRNA transcript enlarged to represent the AUG translation start codon, two consecutive tryptophan amino acid codons (UGGUGG), and 4 regions (1, 2, 3, and 4) that base pair to form different hairpin-loop structures in the mRNA leader region. Suppose a mutant bacteria has region 3 of the trp operon attenuator region mutated so that it cannot base pair normally. Would the bacteria grow in the absence of the amino acid tryptophan? (hint: in order for bacteria to grow in absence of tryptophan it should be able to synthesize its own tryptophan) Leader region trpE trpD trpC trpB trpA DNA 5' 3' Transcription trp leader sequence MRNA AUG UGGUGG UUUUUU 1 2 3 (tryptophan codons) There is insufficient information to answer the question. Yes No O O
Please complete the table representing the regulation of the lactose operon. Please highlight any data that provides evidence of trans regulation.
Given the Table below concerning the lac operon, match the letter with what would be occurring for each scenario. Repressor is bound to the operator, cAMP complex is bound and transcription is prevented. Allolactose is bound to the repressor, cAMP complex is bound, and transcription is prevalent. Allolactose is bound to the repressor, cAMP complex is not assembled, and transcription is slow Repressor is bound to the operator, cAMP complex is not assembled, and transcription is prevented.
A constitutive mutation in the lac operon may be of several types. [Note that constitutive means that the structural genes are always expressed, even if lactose is absent.] Name two types of constitutive mutations. Group of answer choices LacY- and LacI- LacOc and LacZ- LacZ- and LacI- LacY- and LacA- LacI- and LacOc
The dlagram below represents the tryptophan operon with the trp leader MRNA transcript enlarged to represent the AUG transiation start codon, two consecutive tryptophan amino acld codons (UGGUGG), and 4 regions (1, 2, 3, and 4) that base pair to form different hairpin-loop structures in the MRNA leader region. What would happen in this MRNA leader region when cells encounter very low levels of tryptophan in Its environment? Leader region trpE trpD trpC trpB trpA DNA 5' 3' Transcription trp leader sequence mRNA UGGUGG (tryptophan codons) AUG UUUUUU 1 3 4. The translating ribosome would stall at the two tryptophan codons, causing the formation of a hairpin-loop botween regions 3 and 4 to promote transcription of the trp operon. The translating ribosome would stall at the two tryptophan codons causing formation of hairpin-loop between regions 2 and 3, which functions as an anti-lerminator of transcription The translating ribosome would stall at the two tryptophan codons causing formation…