Exam 28: Regulation of Gene Expression

A) an ionic interaction between an arginine and the phosphate group
B) a serine donating a hydrogen bond to N7 of adenine
C) a threonine donating a hydrogen bond to the NH₂ substituent at position 6 of adenine
D) a serine donating a hydrogen bond to a phosphate oxygen
E) a backbone NH group donating a hydrogen bond to the 2´ OH

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A) The level of cyclic AMP will be low.
B) The CRP (cAMP receptor protein) cannot bind to its target DNA.
C) If lactose is present, synthesis of lac operon mRNA will occur at a high level.
D) A repressor is activated by cyclic AMP and will prevent the binding of RNA polymerase to the lac operon promoter.
E) None of the statements is true.

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A) a mutation in the repressor gene that strengthens the affinity of the repressor for the operator.
B) a mutation in the repressor gene that weakens the affinity of the repressor for the operator.
C) a mutation in the repressor gene that weakens the affinity of the repressor for the inducer.
D) binding of the repressor to the operator.
E) the presence of glucose in the growth medium.

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A) the major groove only
B) the minor groove only
C) the backbone only
D) both the backbone and the major groove
E) both the backbone and the minor groove

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The lac operon is a set of genes that ar...

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A) The leader peptide will contain multiple instances of the amino acid produced by the operon.
B) Transcription attenuation will always be accompanied by other positive or negative regulatory mechanisms.
C) Trancription will be reduced under conditions where concentration of the amino acid produced by the operon is high.
D) Synthesis of the leader peptide depends on the concentration of the aminoacylated tRNA, not the amino acid directly.
E) All of these statements are true.

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A) The small molecule activates transcription by decreasing inhibition by the protein.
B) The small molecule inhibits transcription by increasing inhibition by the protein.
C) The small molecule activates transcription by increasing activation by the protein.
D) The small molecule inhibits transcription by decreasing activation by the protein.
E) None of these statements is reasonable.

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A) negative regulation and transcription attenuation
B) negative regulation and positive regulation
C) positive regulation and transcription attenuation
D) negative regulation only
E) transcription attenuation only

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In E. coli, the synthesis of ribosomal p...

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A) Access to eukaryotic promoters is restricted by the structure of chromatin.
B) Most regulation is positive, involving activators rather than repressors.
C) Larger and more multimeric proteins are involved in regulation of eukaryotic transcription.
D) Transcription and translation are separated in both space and time.
E) Strong promoters in eukaryotes are generally fully active in the absence of regulatory proteins.

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The lac operon is a classic example of g...

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When analyzing transcriptional regulatio...

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A) It increases transcription by binding to all $\sigma$ subunits.
B) It decreases transcription by binding to all $\sigma$ subunits.
C) It increases transcription by binding to a specific $\sigma$ subunit.
D) It increases transcription by binding to RNA polymerase.
E) It decreases transcription by inhibiting binding by RNA polymerase.

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A) to form tertiary RNA structures in mRNA
B) to bind to small molecules
C) to inhibit the initiation of translation
D) to prevent ribosome binding to the Shine-Dalgarno sequence
E) All of the answers are correct.

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The leader peptide in prokaryotes such a...

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A) unchanged.
B) increased.
C) always decreased.
D) only decreased in the absence of Trp.
E) It cannot be determined from the information given.

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A) feedforward activation
B) transcriptional induction
C) feedback inhibition
D) attentuation
E) constitutive gene expression

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