Question 1

What is a role of the aptamer in riboswitches?

Accepted Answer

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. 
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.

Question 2

If binding of a small molecule to a regulatory protein lowers the Kd of the protein/operator binding interaction, what can reasonably be stated?

Accepted Answer

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. 
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.

Question 3

What two kinds of regulation exist for the lac operon in E. coli?

Accepted Answer

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 
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

Question 4

If an amino acid is part of a nonspecific DNA:protein interaction, with what parts of DNA is it likely to interact?

Accepted Answer

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 
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

Question 5

The lac operon includes the open reading frame for the permease (lacY) that is necessary for lactose import. How then does lactose get into the cell to activate transcription of the lac operon?

Accepted Answer

The lac operon is a classic example of g

Question 6

Which term BEST describes the process of increasing mRNA production for a gene in response to a stimulus?

Accepted Answer

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

Question 7

Match the protein or structural feature on the left with one appropriate description on the right.
____ Activator
(a) A positive regulator
____ Helix-turn-helix
(b) A negative regulator
____ Leucine zipper
(c) Facilitates transcription only when bound to a signal
____ Repressor
molecule
____ Zinc finger
(d) A DNA-binding structural motif found in many
prokaryotic regulatory proteins
(e) A structural feature involved in protein-protein interactions
between some regulatory protein monomers
(f) A protein that dissociates from DNA when bound to a
signal molecule
(g) A DNA-binding structural motif found in many eukaryotic
regulatory proteins

Accepted Answer

Activator - (c) Facilitates transcriptio

Question 8

When analyzing transcriptional regulation by carrying out Northern blots, the RNA of housekeeping genes is typically examined in parallel with the gene of interest. Why would this be important?

Accepted Answer

When analyzing transcriptional regulatio

Question 9

Which noncovalent interaction is NOT a possible between cAMP and cAMP receptor protein (CRP)?

Accepted Answer

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 
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

Question 10

Explain how synthesis of ribosomal proteins in E. coli is regulated at the level of translation.

Accepted Answer

In E. coli, the synthesis of ribosomal p

Question 11

What is NOT a common feature found in steroid hormone receptors?

Accepted Answer

A) a DNA-binding region 
B) a transcription activation region 
C) a hormone binding region 
D) zinc finger motifs 
E) 
luecine zipper motifs 
A) a DNA-binding region 
B) a transcription activation region 
C) a hormone binding region 
D) zinc finger motifs 
E) 
luecine zipper motifs

Question 12

Which statement describes the role of the upstream promoter (UP) element in E. coli?

Accepted Answer

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. 
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.

Question 13

What statement is NOT true regarding transcription attenuation of amino acid biosynthetic operons?

Accepted Answer

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. 
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.

Question 14

Which outcome will be TRUE when E. coli is grown in the absence of glucose?

Accepted Answer

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. 
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.

Question 15

By increasing the spacing between sequence 1 and sequence 2 in the leader peptide of the trp operon of E. coli, attenuation compared with the normal sequence is:

Accepted Answer

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

Question 16

Transcription of the lactose operon in E. coli is stimulated by:

Accepted Answer

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. 
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.

Question 17

Match the molecule with its role in the lac operon. Note that a given molecule may have more than one role.

Accepted Answer

The lac operon is a set of genes that ar

Question 18

In prokaryotes such as E. coli, many operons that encode enzymes involved in amino acid biosynthesis begin with a sequence coding for a leader peptide. This peptide has no known enzymatic function and is rich in the amino acid that is synthesized by the enzymes coded for in the operon. What is the function of this leader peptide?

Accepted Answer

The leader peptide in prokaryotes such a

Question 19

Which statement about eukaryotic versus prokaryotic gene regulation is NOT correct?

Accepted Answer

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. 
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.

Exam 28: Regulation of Gene Expression

What is a role of the aptamer in riboswitches?

If binding of a small molecule to a regulatory protein lowers the Kd of the protein/operator binding interaction, what can reasonably be stated?

What two kinds of regulation exist for the lac operon in E. coli?

If an amino acid is part of a nonspecific DNA:protein interaction, with what parts of DNA is it likely to interact?

The lac operon includes the open reading frame for the permease (lacY) that is necessary for lactose import. How then does lactose get into the cell to activate transcription of the lac operon?

Which term BEST describes the process of increasing mRNA production for a gene in response to a stimulus?

When analyzing transcriptional regulation by carrying out Northern blots, the RNA of housekeeping genes is typically examined in parallel with the gene of interest. Why would this be important?

Which noncovalent interaction is NOT a possible between cAMP and cAMP receptor protein (CRP)?

Explain how synthesis of ribosomal proteins in E. coli is regulated at the level of translation.

What is NOT a common feature found in steroid hormone receptors?

Which statement describes the role of the upstream promoter (UP) element in E. coli?

What statement is NOT true regarding transcription attenuation of amino acid biosynthetic operons?

Which outcome will be TRUE when E. coli is grown in the absence of glucose?

By increasing the spacing between sequence 1 and sequence 2 in the leader peptide of the trp operon of E. coli, attenuation compared with the normal sequence is:

Transcription of the lactose operon in E. coli is stimulated by:

Match the molecule with its role in the lac operon. Note that a given molecule may have more than one role.

Which statement about eukaryotic versus prokaryotic gene regulation is NOT correct?

The Foundations of Biochemistry

Water

Amino Acids, Peptides, and Proteins

The Three-Dimensional Structure of Proteins

Protein Function

Enzymes

Carbohydrates and Glycobiology

Nucleotides and Nucleic Acids

DNA-Based Information Technologies

Lipids

Biological Membranes and Transport

Biosignaling

Bioenergetics and Biochemical Reaction Types

Glycolysis, Gluconeogenesis, and the Pentose Phosphate Pathway

Principles of Metabolic Regulation

The Citric Acid Cycle

Fatty Acid Catabolism

Amino Acid Oxidation and the Production of Urea

Oxidative Phosphorylation and Photophosphorylation

Carbohydrate Biosynthesis in Plants and Bacteria

Lipid Biosynthesis

Biosynthesis of Amino Acids, Nucleotides, and Related Molecules

Hormonal Regulation and Integration of Mammalian Metabolism

Genes and Chromosomes

DNA Metabolism

RNA Metabolism

Protein Metabolism

Filters

If binding of a small molecule to a regulatory protein lowers the K_d of the protein/operator binding interaction, what can reasonably be stated?