Homework Answers
Q-1) D OFF ( both repressed and activated , but the repressor "wins").
When both glucose and lactose are absent, the repressor blocks transcription.When glucose is unavailable, cAMP binds to CAP, making CAP able to bind DNA. Bound CAP helps RNA polymerase attach to the lac operon promoter. If lactose is available, the lac repressor will be released from the operator. This allows RNA polymerase to move forward on the DNA and transcribe the operon. But if lactose also absent, no transcription of the lac operon occurs as the lac repressor will also be bound to the operator (due to the absence of allolactose), acting as a roadblock to RNA polymerase and preventing transcription.
Q-2) B when glucose is absent , but lactose is present.
Maximal transcription of the lac operon occurs only when glucose is absent and lactose is present.
Q-3) Option A is correct. A promoter that isn't regulated by activators or repressors, so that there is always transcription occurring (at some level, not necessarily high).
constitutive promoter is an unregulated promoter that allows for continual transcription of its associated gene.
Add Answer to:
If we placed a bacterium into a medium that contained neither lactose nor glucose (let's give...
In E coli the lac operon will express enzymes for the digestion of (Glucose/Lactose) when it...
In E coli the lac operon will express enzymes for the digestion of (Glucose/Lactose) when it is present, but if both the sugar mentioned before and (Glucose/ Lactose) are present the lac operon is repressed, resulting in the (Glucose/ Lactose) being used first. If there are high levels of cAMP, this means (Glucose/Lactose) levels are low, this results in a (Represser/Promoter) being activated and (Decreasing/Increasing) transcription of the lac operon.
The gene machine program shows you what happens when lactose is present in E. coli, and...
The gene machine program shows you what happens when lactose is present in E. coli, and how the lac operon is under negative control. However, the lac operon is also under positive control from a protein called CRP, eAMP Receptor Protein. The absence of the lac repressor is essential but not sufficient for effective transcription of the lac operon. RNA polymerase also depends on the presence of CRP. Like the lac repressor, which can bind to the DNA and lactose....
Yet, all the cells in your body contain the same genes (and same alleles). The difference...
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...
A number of mutations affect the expression of the lactose operon in E. coir. I^- a...
A number of mutations affect the expression of the lactose operon in E. coir. I^- a mutant lac repressor that cannot bind the lac operator I^s a mutant lac repressor that cannot bind lactose O^c a mutant lac operator that cannot bind repressor Lacl P^- a mutant lac promoter that cannot bind RNA polymerase Z^- a mutant lacZ lost beta-galactosidase activity Y^- a mutant permease that cannot transport lactose into the cell Consider the following strains each with the indicated...
Fill in the blanks in the following sentences by selecting from the drop-down menus. When E.coli...
Fill in the blanks in the following sentences by selecting from the drop-down menus. When E.coli cells are grown in the presence of high glucose and high lactose, the lac repressor is not bound to the lac operator, CAMP levels in the cell are high and CAP is mostly bound to the CAP binding site in the lac promoter. Under these conditions, transcription of the lac operon Select When E.coli cells are grown in the absence of glucose and presence...
1) Which of the following conditions is most likely to cause the lactose operon to be...
1) Which of the following conditions is most likely to cause the lactose operon to be transcribed? A) There is more glucose in the cell than lactose. B) There is glucose but no lactose in the cell. C) The cyclic AMP and lactose levels are both high within the cell. D) The CAMP level is high and the lactose level is low. 2) How does the transcription of structural genes in an inducible operon occur? A) It occurs continuously in...
Imagine you are carrying out research on the lac operon. You isolate six mutations in the...
Imagine you are carrying out research on the lac
operon. You isolate six mutations in the lac operon by
measuring the amount of beta-galactosidase made in mutant cell line
under three different conditions: no lactose/no glucose; lactose
only; and lactose/glucose. Your results are shown in the table.
Strain
No Lactose, No Glucose
Lactose
Lactose, Glucose
Wild-type
None
High
Low
Mutant 1
None
None
None
Mutant 2
None
None
None
Mutant 3
None
Low
Low
Mutant 4
None
Low
Low
Mutant...
1) The lac operon is… a) Positive repressible b) Both negative inducible and positive repressible c)...
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...
26. The lac operon in E. coli consists of genes that code for enzymes necessary for...
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...
Consider what you know about the lac operon, and predict whether the repressor and the activator...
Consider what you know about the lac operon, and predict whether the repressor and the activator is active (able to bind to DNA) or inactive (unable to bind to DNA), and the level of transcription in the following scenarios. Options for transcription levels include high, medium, leaky and off. a. When lactose is present but glucose is not, the repressor is and the activator is leading to levels of transcription. and the activator is b. When lactose and glucose are...
The gene machine program shows you what happens when lactose is present in E. coli, and how the lac operon is under negative control. However, the lac operon is also under positive control from a protein called CRP, eAMP Receptor Protein. The absence of the lac repressor is essential but not sufficient for effective transcription of the lac operon. RNA polymerase also depends on the presence of CRP. Like the lac repressor, which can bind to the DNA and lactose....
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...
A number of mutations affect the expression of the lactose operon in E. coir. I^- a mutant lac repressor that cannot bind the lac operator I^s a mutant lac repressor that cannot bind lactose O^c a mutant lac operator that cannot bind repressor Lacl P^- a mutant lac promoter that cannot bind RNA polymerase Z^- a mutant lacZ lost beta-galactosidase activity Y^- a mutant permease that cannot transport lactose into the cell Consider the following strains each with the indicated...
Fill in the blanks in the following sentences by selecting from the drop-down menus. When E.coli cells are grown in the presence of high glucose and high lactose, the lac repressor is not bound to the lac operator, CAMP levels in the cell are high and CAP is mostly bound to the CAP binding site in the lac promoter. Under these conditions, transcription of the lac operon Select When E.coli cells are grown in the absence of glucose and presence...
1) Which of the following conditions is most likely to cause the lactose operon to be transcribed? A) There is more glucose in the cell than lactose. B) There is glucose but no lactose in the cell. C) The cyclic AMP and lactose levels are both high within the cell. D) The CAMP level is high and the lactose level is low. 2) How does the transcription of structural genes in an inducible operon occur? A) It occurs continuously in...
Imagine you are carrying out research on the lac
operon. You isolate six mutations in the lac operon by
measuring the amount of beta-galactosidase made in mutant cell line
under three different conditions: no lactose/no glucose; lactose
only; and lactose/glucose. Your results are shown in the table.
Strain
No Lactose, No Glucose
Lactose
Lactose, Glucose
Wild-type
None
High
Low
Mutant 1
None
None
None
Mutant 2
None
None
None
Mutant 3
None
Low
Low
Mutant 4
None
Low
Low
Mutant...
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...
Consider what you know about the lac operon, and predict whether the repressor and the activator is active (able to bind to DNA) or inactive (unable to bind to DNA), and the level of transcription in the following scenarios. Options for transcription levels include high, medium, leaky and off. a. When lactose is present but glucose is not, the repressor is and the activator is leading to levels of transcription. and the activator is b. When lactose and glucose are...
Most questions answered within 3 hours.
-
What are the differences between an antibiotic, a semisynthetic,
and a synthetic as types of antimicrobials?
asked 1 minute ago -
Please answer ASAP 2) Choose a point at random from the unit
square [0, 1] ×...
asked 2 minutes ago -
Draw the Lewis structures and determine which of these
molecules has a central atom that unavoidably...
asked 2 minutes ago -
Do we typically carry antibodies against the RH antigen in our
blood plasma?
asked 5 minutes ago -
One mole of oxygen gas is at a pressure of 5.90 atm and a
temperature of...
asked 8 minutes ago -
The primary side of a transformer has 935 turns and is connected
to 118 Volts A/C....
asked 7 minutes ago -
This must be done in Java and it must contain a public static
void (string []args)...
asked 10 minutes ago -
An economy has a Cobb–Douglas production function:
Y=Kα(LE)1−αY=Kα(LE)1−α
The economy has a capital share of 0.30,...
asked 25 minutes ago -
60.0 mL of a silver chlorate solution with a concentration of
0.654 M is mixed with...
asked 30 minutes ago -
Asked if he has any regrets about the way he's handled the
coronavirus crisis so far,...
asked 41 minutes ago -
True or False?
Considering a door as a rigid body. Its angular motion happens
in a...
asked 45 minutes ago -
In
IUPAC naming, do we concider the prefix in alphabatizing?
In other words do we look...
asked 50 minutes ago