9 Which of the following statements about the lac operon is accurate?a) The repressor only leaves the operator when it is bound to the proteinproduct of the lacl gene.b)The repressor is always bound to the operator, but changes shape whenlactose binds to it, allowing RNA polymerase to pass.c)The repressor only binds to the operator when it is bound to the product ofthe enzymes coded for by the genes of the operon.d)The repressor is bound to the operator, except when it is bound to theinducer.

The lac operon is a cluster of genes in bacteria responsible for lactose metabolism. It consists of…

Which of the following statements about the la a) The repressor only leaves the operator v product of the lacl gene. b) The repressor is always bound to the op lactose binds to it, allowing RNA polyme c) The repressor only binds to the operator the enzymes coded for by the genes of t d) The repressor is bound to the operator, inducer.

Which of the following statements about the la a) The repressor only leaves the operator v product of the lacl gene. b) The repressor is always bound to the op lactose binds to it, allowing RNA polyme c) The repressor only binds to the operator the enzymes coded for by the genes of t d) The repressor is bound to the operator, inducer.

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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A mutation that inactivates the repressor gene of the lac operon results in (a) the continuous transcription of the structural genes (b) no transcription of the structural genes (c) the binding of the repressor to the operator (d) no production of RNA polymerase (e) no difference in the rate of transcription
. What is the role of catabolite activator protein (CAP) in the lactose operon of E. coli? it prevents RNA polymerase from binding to the promoter when lactose levels are high it assists RNA polymerase in binding to the promoter when glucose levels are high it prevents RNA polymerase from binding to the promoter when glucose levels are low it assists RNA polymerase in binding to the promoter when glucose levels are low it prevents RNA polymerase from binding to the promoter when lactose levels are low
Let’s suppose you have isolated a mutant strain of E. coli in which the lac operon is constitutively expressed. In other words, the operon is turned on in the presence or absence of lactose. One possibility is that the mutation may block the transcription of the lacI gene, thereby preventing the synthesis of lac repressor. A second possibility is that the mutation could alter the sequence of the lac operon in a way that prevents the repressor protein from binding to the operator. How would you distinguish between these two possibilities?
In the tryptophan operon of E. coli, what happens when tryptophan levels get too high? tryptophan is removed from its co-repressor, causing it to detach from the operator tryptophan is removed from its co-repressor, causing it to attach to the operator tryptophan is bound to its co-repressor, causing it to detach from the operator tryptophan is bound to its co-repressor, causing it to attach to the operator all of the above occur at equal rates when tryptophan levels get too high (Option C is the answer for the question above) What effect will the above process have on the tryptophan operon? RNA polymerase will detach from the promoter, initiating transcription RNA polymerase will detach from the promoter, stopping transcription RNA polymerase will attach to the promoter, initiating transcription RNA polymerase will attach to the promoter, stopping transcription all of the above occur at equal rates when tryptophan levels get too high
In the tryptophan operon of E. coli, what happens when tryptophan levels get too high? tryptophan is removed from its co-repressor, causing it to detach from the operator tryptophan is removed from its co-repressor, causing it to attach to the operator tryptophan is bound to its co-repressor, causing it to detach from the operator tryptophan is bound to its co-repressor, causing it to attach to the operator all of the above occur at equal rates when tryptophan levels get too high (Option D is the answer for the question above) What effect will the above process have on the tryptophan operon? RNA polymerase will detach from the promoter, initiating transcription RNA polymerase will detach from the promoter, stopping transcription RNA polymerase will attach to the promoter, initiating transcription RNA polymerase will attach to the promoter, stopping transcription all of the above occur at equal rates when tryptophan levels get too high
In the tryptophan operon of E. coli, what happens when tryptophan levels get too high? tryptophan is removed from its co-repressor, causing it to detach from the operator tryptophan is removed from its co-repressor, causing it to attach to the operator tryptophan is bound to its co-repressor, causing it to detach from the operator tryptophan is bound to its co-repressor, causing it to attach to the operator all of the above occur at equal rates when tryptophan levels get too high What effect will the above process have on the tryptophan operon? RNA polymerase will detach from the promoter, initiating transcription RNA polymerase will detach from the promoter, stopping transcription RNA polymerase will attach to the promoter, initiating transcription RNA polymerase will attach to the promoter, stopping transcription all of the above occur at equal rates when tryptophan levels get too high
How does the repressor protein contribute to selective expression of the structural genes Z, Y, and A in the lac operon? The repressor protein is only expressed when lactose is present. The repressor is always expressed. It blocks transcription when lactose is present. The repressor is always expressed. It allows transcription when lactose is absent. The repressor is always expressed. It blocks transcription when lactose is absent. The repressor protein is only expressed when lactose is absent.
What would happen if the operator sequence of the lac operon contained a mutation that prevented the repressor protein from binding the operator? (Explain what would happen both in the presence and absence of lactose)
What would happen if the operator sequence of the trp operon contained a mutation that prevented the repressor protein from binding to the operator? (Explain what would happen in both the presence and absence of tryptophan)
According to the operon model, for the synthesis of an inducible enzyme to occur, the end-product must not be in excess an inducer must bind to the enzyme an inducer must bind to the repressor repressor must bind to the operator repressor must not be synthesized
The lac operon produces enzymes that allow the bacteria E. coli to metabolize lactose, it is in an inducable operon. When lactose is present, will the repressor protein attach or leave the operon? How would this effect the production of lactose producing enzymes?
In the lac operon, the lacZ gene codes for an enzyme called ____________, which catalyze the breakdown of the sugar __________ into monosaccharides. This enzyme can also hydrolyze the sugar analog ____________, which produces blue pigments following its breakdown. Since the lac operon is not always on the bacterial cells, we add the chemical ________ which prevents the lac depressor from binding to the operators, leading to constitutive expression of the operon.