1. The B-galactosidase gene of the lac operon is expressed at high level when which combination of following conditions is met? A. Select one answer for each of the following. Lactose concentration low high Lac Repressor Protein Inactive Active CAMP concentration low high Catabolite Activator Protein (CAP) Inactive Active B. Describe a mutation in a noncoding regulatory element that would result in constitutively high ß-galactosidase expression in the presence of both low glucose and low lactose. Explain its effect on gene regulation.

1. The B-galactosidase gene of the lac operon is expressed at high level when which combination of following conditions is met? A. Select one answer for each of the following. Lactose concentration low high Lac Repressor Protein Inactive Active CAMP concentration low high Catabolite Activator Protein (CAP) Inactive Active B. Describe a mutation in a noncoding regulatory element that would result in constitutively high ß-galactosidase expression in the presence of both low glucose and low lactose. Explain its effect on gene regulation.

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Description: 1. The B-galactosidase gene of the lac operon is expressed at high level when which combinationof following conditions is met?A. Select one answer for each of the following.Lactose concentrationlowhighLac Repressor ProteinInactiveActiveCAMP concentr

Biology 2e

2nd Edition

ISBN:9781947172517

Author:Matthew Douglas, Jung Choi, Mary Ann Clark

Publisher:Matthew Douglas, Jung Choi, Mary Ann Clark

Chapter16: Gene Expression

Section: Chapter Questions

Problem 9RQ: The a/a operon is an inducible operon that controls the production of the sugar arabinose. When...

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4) Suppose you have an E. coli in which the gene that codes for the lac repressor protein has been mutated in such a way that the protein produced can bind to both lactose and DNA (at its specific binding site in the lac operon promoter) simultaneously. What effect, if any, would this have on regulation of expression of the lac operon? Briefly (1 sentence) explain why you would predict the effect or lack of effect this mutation would have.
One of the main lessons of this chapter is that severalbacterial genes are often transcribed from a singlepromoter into a large multigene (polycistronic) transcript. The region of DNA containing the set of genesthat are cotranscribed, along with all of the regulatoryelements that control the expression of these genes, iscalled an operon.a. Which of the mechanisms in the following listcould explain differences in the levels of themRNAs for different operons?b. Which of the mechanisms in the following listcould explain differences in the levels of theprotein products of different genes in the sameoperon?i. Different promoters might have different DNAsequences.ii. Different promoters might be recognized bydifferent types of RNA polymerase.iii. The secondary structures of mRNAs might differ so as to influence the rate at which they aredegraded by ribonucleases.PROBLEMSProblems 575a. Why did the mating with a nonlysogenic recipientresult in phage growth and release, but the infectionof a…
You are growing E. coli in a laboratory in order to study their operons. The growth media you are using contains lactose, no glucose and no tryptophan. Using your knowledge of operons and their regulation, answer the following questions I really need a in depth epxplantion for the queshtions to make sure i understand the answers a.What effect does lactose have on the bacterial cell’s lac operon? b.What does the absence of glucose do to the bacterial cell? c.You now add tryptophan to the cell. What would happen to the bacterial cell and its trp operon? d.What kind of regulation does lactose provide to an operon’s repressor?
Suppose that you have isolated a mutant strain of E. coli inwhich the lac operon is constitutively expressed. To understandthe nature of this defect, you create a merozygote in which themutant strain contains an F′ factor with a normal lac operonand a normal lacI gene. You then compare the mutant strain andthe merozygote with regard to their β-galactosidase activities inthe presence and absence of lactose. You obtain the followingresults:
IPTG can be used in the laboratory as a synthetic inducer of the lac operon, instead of lactose. Based on your knowledge of the regulation of the lac operon, predict with explanation whether these gene products (B-galactosidase, lactose Permease) will be produced. a IPOZY IPOZY b. IP'O'Z'Y/IPOZY" +IPTG B-galactosidase -IPTG Permease B-galactosidase Permease Only typed answer. Will upvote you immediately. Please help
. 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?
F’ lac I- O+ Z+/ lac I+ Oc Z- the genotype indicated would lead to what type of expression of β‐galactosidase with respect to lactose inducibility of the lac operon. A. Constitutive B. Cannot be determined C. Inducible D. Uninducible
Explain why (a) inactivation of the O2 or O3 sequence of the lac operon causes only a twofold loss in repression, and (b) inactivation of both O2 and O3 reduces repression ∼70-fold.
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
Match each description with the appropriate label (allo)Lactose binds to the lac repressor, causing it to release from the promoter CAP binds CAMP to stimulate transcripti of the lac operon ✓ [Choose ] positive control of an inducible gene negative control of an inducible gene [Choose]
Consider this strain of E. coli with lac operon alleles: IS pt o* z* y+ /T p* oCz- Y+ In a written response, briefly explain if beta-galactosidase AND permease will be expressed, and if so, will they be inducible or constitutive.
Describe the mechanism by which cAMP receptorprotein (CRP), the regulatory protein for catabolite repression, functions. Use the lactose operon as an example.