Please answer item number 8 and 9. Answer as Directed. Below is the model of a lac operon.lac Zlac Ipromoter operatorсlac Ylac ADNA1. What are structural genes? Are the lac structural genes transcribed in the absence oflactose?2. What is the role of the promoter and operator sites in the operon?3. Is the repressor protein bound to the operator site in the absence of lactose? In itsabsence?4. Under what nutritional circumstances (high or low glucose) is CAP bound to cAMP?5. In the absence of lactose and the presence of glucose in the bacterial growth media,what proteins are bound to the lac control region? Is the operon being transcribed then?6. In the presence of lactose and the presence of glucose in the bacterial growth media,what proteins are bound to the lac regulatory region? Is the operon being transcribedthen?7. In the presence of lactose and the absence of glucose in the bacterial growth media,what proteins are bound to the lac control region?8. Why is it adaptive for a bacterium to not express the genes that encode for that lactoseutilization proteins when lactose is not available or when glucose is present?9. Why is it adaptive for the structural genes for using lactose to be under the control of asingle promoter, i.e., synthesize a polycistronic message rather than threemonocistronic message?

Bacteria are able to adapt to their environment by regulating the expression of genes that encode…

8. Why is it adaptive for a bacterium to not express the genes that encode for that lactose utilization proteins when lactose is not available or when glucose is present? 9. Why is it adaptive for the structural genes for using lactose to be under the control of a single promoter, i.e., synthesize a polycistronic message rather than three monocistronic message?

8. Why is it adaptive for a bacterium to not express the genes that encode for that lactose utilization proteins when lactose is not available or when glucose is present? 9. Why is it adaptive for the structural genes for using lactose to be under the control of a single promoter, i.e., synthesize a polycistronic message rather than three monocistronic message?

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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Plz answer ASAP. I will thumb up You are studying the regulation of the lactose operon in Escherichia coli, by measuring expression of the lacZ gene (i.e production of beta-galactosidase).(a) You identify several loss-of-function mutations in which lacZ is never expressed, in the presence and absence of glucose and lactose. What components of the lac operon could be mutated to produce this phenotype? List all possibilities.
Please help me iwht this question explain how the regulation of the Lac Operon incorporate both negative and positive regulation?
Choose correct option and do explain plz. 1. The protein complex that helps RNA polymerase to cross nucleosomes during extension is:a. SWI-SNFb. poly A polymerasac. TFIISd. FACT 2. The polydenylation is carried out by:a. primaseb. polymers poly ac. a reverse transcriptased. adenylyltransferase 3. The lactose operon produces a polycistronic mRNA that includes four genes: Lacl, LacZ, LacY and LacA. True or false?
PREDICT Compare the types of bacterial genes associated with inducible operons, those associated with repressible operons, and those that are constitutive. Predict the category into which each of the following would most likely fit: (a) a gene that codes for RNA polymerase, (b) a gene that codes for an enzyme required to break down maltose, and (c) a gene that codes for an enzyme used in the synthesis of adenine.
For the E. coli lac operon, when lactose is present: a. and glucose is absent, cAMP binds and activates catabolicactivator protein (CAP). b. and glucose is absent, the level of cAMP decreases. c. activated CAP binds the repressor protein to remove it from the operator gene. d. the cell prefers lactose over glucose. e. RNA polymerase cannot bind to the promoter.
The a/a operon is an inducible operon that controls the production of the sugar arabinose. When arabinose is present in a bacterium it binds to the protein AraC, and the complex binds to the initiator site to promote transcription. In this scenario, AraC is a(n). activator inducer repressor operator
Using the lac operon as a model, explain the role of inducers, repressors, and inducer exclusion.
. Recall that the trp operon has a special leader sequence (trpL) between the operator and the structural genes that offers attenuation as a mechanism for regulation of gene expression. (A) Draw a diagram of a trpL region of the operon when tryptophan is abundant in the cell.Label the following features: the DNA, 5’ and 3’ polarity of the RNA, the regions 1, 2, 3,and 4 and poly-U of the RNA, the pair of Trp codons (UGG), the ribosome, and RNA-Pol,along with any stem-loop structure that would form under these conditions (B) In the above example, will the rest of the trp operon genes be expressed? Briefly describe your reasoning why or why not (C) The trp codons in region 1 of the trpL gene have mutated to cysteines (UGG to UGC). What will be the effect on attenuation gene regulation of the trp operon? Brieflyexplain your reasoning.
Tonly in cell biology the Lac operon in bacteria encodes proteins required to import and digest the disaccharide lactose in the absence of glucose. Lac operon is highly expressed only when two conditions are met: glucose must be absent and lactose must be present. Bacteria solves this issue by employing both an activator and a repressor for the same operon. But how? A Bacteria can turn on Lac operon even if the repressor is bound to the operator region. B When the two conditions are met repressor will not be present, activator will be active. Thus the operon will be ON. C Operon is always on when the repressor is not bound. D Operon will be off when the activator is bound and repressor is not. E Activators itself inhibit repressors from binding to operators.
Regulation of Genes and Their products 1. Given the following genotypes, explain how the mutation (identified by a (-) superscript) wil affect E. coll grown in lactose medium. Will the lac operon be on or off? Will there be a complete set of gene products from the lac operon? What will be the implication of the missing gene product, if ever? Will the cell be able to survive in the lactose medium or not? a. I+p+o+z- y+ b. i- p+o+z+y+ c. i+p+o- z+y+ d. i+p- o+z+y+ 2. In terms of the trp operon, differentiate between two normal bacterial cultures, one grown in a medium supplied with tryptophan and the other medium without tryptophan. 3. Experiments show that mutations at gene E lead to non-repressible transcription of trp genes. Why?
Two closely linked open reading frames (ORFs) have been identified on the E. coli chromosome and they are predicted to encode genes sugX sugY which is involved in the catabolism (utilization) of a non-glucose sugar. In the figure below, the top line (with the big arrow) is the coding strand, and the bottom line is the non-coding (template) strand of the operon. Since the RNA sequence would be the “same” as the coding strand, please label (show the location of), in relation to the ORFs, the promoter(s) and 4 other genetic elements in this region that may be involved in the transcription and translation of sugX and sugY as well as the regulation of their expression. (Note: genetic elements are the regions of DNA or RNA.) If you are not comfortable with the coding strand of the DNA, feel free to draw the mRNA strand underneath and label the relevant features on the RNA strand, but the RNA strand must be aligned with the DNA strands in position and scale. Leader(s)/antileader(s) and…
1c In context with transcription of prokaryotic genes briefly describe the effect the lac repressor protein has on transcription of the lac operon when it is bound to its binding site and the lac operon promoter, and how it accomplishes the effect.