An operon in E. coli called the Pur operon, encodes proteins responsible for purine biosynthesis. Two genes, purA and purB are under the control of a single promoter and operator, similar to the arrangement in the lac and trp operons. A repressor protein, purR, binds to the operator. In what conditions (high purine or low purine) do you suppose this repressor binds to the operator? Do you consider this a “repressible” or “inducible” operon?
In case of high purine the repressor binds to the operator. As the purin is already high and no further purin is required the repressor binds the operator and switch off the pur operon.
This is a "repressible" operon because the presence of purin repress or switch of the operon.
An operon in E. coli called the Pur operon, encodes proteins responsible for purine biosynthesis. Two...
please help me with the question 15 to 18.
Basic structure of an operon Note that the diagram below is one section of DNA master strend with some areas of DNA labeled in blocks The bracketed area illustrates the basic parts of an operon repressor gene promoter operator structural genes DNA 3 mRNA 5 - 3 repressor protein shown attached to operator #2 Repressor preten "Use purple to color in the repressor gene. The repressor gene codes for a repressor...
1) The lac operon is… a) Positive repressible b) Both negative inducible and positive repressible c) Positive inducible d) Negative inducible 2) An activator regulatory protein… a) Is involved in negative regulatory control b) Is a cis acting regulatory element c) Recruits RNA polymerase to the promoter d) Prevents RNA polymerase from binding the promoter 3) For the lac operon, the presence of the substrate (lactose) activates the repressor. True or False? a) true b) false 4) cAMP… a) Activates...
Yet, all the cells in your body contain the same
genes (and same alleles). The difference across cell types
is that genes get selectively expressed (turned on or off)
based on the proteins needed for cellular function given their
environment.
Select which statement explains the reason why hair does not
normally grow on your muscle cells.
a.
Muscle cells have the gene for keratin, but do not express
it
b.
Muscle cells do not have the gene for keratin and...
26. The lac operon in E. coli consists of genes that code for enzymes necessary for the breakdown of lactose. When lactose is absent, the operon is inactive because a repressor protein binds to a specific site in the lac operon. When lactose is present, lactose molecules bind to the repressor protein, causing the repressor protein to dissociate from the binding site. In the absence of glucose (a preferred energy source for bacteria), the protein CAP binds to a regulatory...
UT EID: D. 5 E. 6 13. For the E. coli strain containing the following alleles of the lac operon, expression of lacZ and lacY is inducible, constitutively on or permanently repressed. (erepressor; r cannot bind operator: osoperator, o cannot bind repressor, lac are LOF mutations) A. lacZ is inducible, lacY is constitutively on. B. lacZ is constitutively on, lacY is inducible. C. lacZ is permanently repressed, lacY is constitutively on. D. lacZ is constitutively on, lacY is permanently repressed....
The E. coli chromosome contains an operon with the following components: an operator, a promoter, and 4 structural genes identified as A,B,C, and D. Diagram this operon in the following manners: A. Inducible, positive regulation. B. Repressible, negative regulation.
The lac operon consists of a promoter that initiates
transcription of the gene i, which encodes a repressor protein. A
seperate promoter, p, within the operon initiates transcription of
z, which encodes B-galactosidase, and y, which encodes permease.
The operator, o, where the repressor protein binds to inhibit
transcription, is positioned between mutations, whereas superscript
c denotes a constitutively active mutant. The table below sea fives
the activity of B-galatosidase and permease for haploid and diploid
mutant strains. Match the...
Page < 2 > of 2 D. The trp operon would be expressed at high levels, comparable to its expression in the absence of trp 6. Based upon what you have learned about the E. coli trp operon, what could you say about expression of its structural genes in cells with large amounts of environmental trp, but expressing a mutant trp repressor that is unable to bind trp? A. The trp operon would be completely repressed due to the abundance...
The following activity will give you practice with the two operons we discussed - the lac operon and the trp operon. Below are two scenarios to consider. You will need to determine whether or not transcription is occurring and describe what is happening in the cell using our operon vocabulary words - regulatory gene, RNA polymerase, operator, promoter, repressor, and genes. 1. Bobby Joe just enjoyed an In and Out milkshake, how will the E. coli in her stomach respond?...
The following activity will give you practice with the two operons we discussed - the lac operon and the trp operon. Below are two scenarios to consider. You will need to determine whether or not transcription is occurring and describe what is happening in the cell using our operon vocabulary words - regulatory gene, RNA polymerase, operator, promoter, repressor, and genes. 1. Bobby Joe just enjoyed an In and Out milkshake, how will the E. coli in her stomach respond?...