QUESTION 2 Effector molecules repress transcription of negatively regulated gene
ID: 62867 • Letter: Q
Question
QUESTION 2
Effector molecules repress transcription of negatively regulated genes by:
A.
Inhibiting activity of repressor proteins.
B.
Stimulating activity of repressor proteins.
C.
Inhibiting activity of activator proteins.
D.
Stimulating activity of activator proteins.
E.
None of the above.
QUESTION 3
Mutations in the operator sequence (e.g., Oc) result in ________ of the lac operon.
A.
Constitutive repression
B.
Constitutive expression
QUESTION 4
Identify the pattern of expression of the lac operon for the following bacterial genotype: I+ P+OCZ-Y+
A.
No expression of permease or -galactosidase.
B.
Constitutive expression of permease, but no -galactosidase.
C.
Constitutive expression of permease and -galactosidase.
D.
Lactose induced expression of permease and -galactosidase.
E.
No expression of permease, but constitutive expression of -galactosidase.
QUESTION 5
The primary control point at which gene expression is regulated in prokaryotes is initiation of ______________.
A.
Transcription
B.
Splicing
C.
Post-translational modification
D.
Nucleus-to-cytosol transport
E.
Translation
QUESTION 6
Which of the following is not a cis-acting element?
A.
-35 promoter region
B.
I gene
C.
Lac operator
D.
CAP binding site
QUESTION 7
ATP is an allosteric effector for the Catabolic Activator Protein (CAP).
True
False
QUESTION 8
The trp operon is controlled by ________________.
A.
Trp repressor.
B.
Attenuation.
C.
Catabolic activator protein (CAP).
D.
A and C.
E.
A and B.
QUESTION 9
Which effector molecule directly interacts with the Lac repressor protein?
A.
cAMP
B.
Glucose
C.
Lactose
D.
ATP
E.
Adenylate cyclase
QUESTION 10
A mutation that makes adenylate cyclase insensitive to glucose metabolites would cause ______________ of the LacZ and LacY genes ___________________ .
A.
transcription, in the presence of glucose and lactose.
B.
constitutive transcription, even in the absence of lactose.
C.
transcription, but no translation.
D.
suppression, under all conditions.
E.
suppression, but only in the presence of glucose.
A.
Inhibiting activity of repressor proteins.
B.
Stimulating activity of repressor proteins.
C.
Inhibiting activity of activator proteins.
D.
Stimulating activity of activator proteins.
E.
None of the above.
Explanation / Answer
Question 4:
The correct option is (A)
Question 5:
A. Transcription
Question 6:
A. -35 promoter region
Question 7:
The statement is True
Question 8:
E. A and B
Question 9:
C. lactose
Question 10: