Question 1

A regulon is a(n):

Accepted Answer

A)  group of related triplet codons. 
B)  network of operons with a common regulator. 
C)  operon that is subject to regulation. 
D)  protein that regulates gene expression. 
E)  ribosomal protein that regulates translation. 
A)  group of related triplet codons. 
B)  network of operons with a common regulator. 
C)  operon that is subject to regulation. 
D)  protein that regulates gene expression. 
E)  ribosomal protein that regulates translation.

Question 2

Which class is expressed in the unfertilized egg and is involved in directing the spatial organization of the Drosophila embryo early in development?

Accepted Answer

A)  gap genes 
B)  homeotic genes 
C)  maternal genes 
D)  segment polarity genes 
E)  segmentation genes 
A)  gap genes 
B)  homeotic genes 
C)  maternal genes 
D)  segment polarity genes 
E)  segmentation genes

Question 3

Which statement about eukaryotic gene regulation is CORRECT?

Accepted Answer

A)  Large polycistronic transcripts are common. 
B)  Most regulation is positive, involving activators rather than repressors. 
C)  Transcription and translation are mechanistically coupled. 
D)  Transcription does not involve promoters. 
E)  Transcription occurs without major changes in chromosomal organization. 
A)  Large polycistronic transcripts are common. 
B)  Most regulation is positive, involving activators rather than repressors. 
C)  Transcription and translation are mechanistically coupled. 
D)  Transcription does not involve promoters. 
E)  Transcription occurs without major changes in chromosomal organization.

Question 4

Which statement does NOT explain why the lac operon would not be effectively regulated by an attenuation mechanism like the trp operon?

Accepted Answer

A)  Lactose is a substrate for the lac operon protein products. 
B)  Products of lac operon enzymes are not used in protein synthesis. 
C)  Transcription and translation do not happen simultaneously for the lac operon. 
D)  Attenuation is a suitable regulatory mechanism for anabolic amino acid pathways. 
E)  All of these statements explain why regulation by attenuation would not be effective for the lac operon. 
A)  Lactose is a substrate for the lac operon protein products. 
B)  Products of lac operon enzymes are not used in protein synthesis. 
C)  Transcription and translation do not happen simultaneously for the lac operon. 
D)  Attenuation is a suitable regulatory mechanism for anabolic amino acid pathways. 
E)  All of these statements explain why regulation by attenuation would not be effective for the lac operon.

Question 5

HMG proteins are named because they migrate rapidly in electrophoresis experiments (high mobility group) relative to other DNA binding proteins (particularly histones). What does this tell you about their amino acid composition?

Accepted Answer

The fact that HMG (High Mobility Group)

Question 6

Describe briefly the general role of the protein products of each of the following types of genes in the embryonic development of the Drosophila: (a) maternal genes; (b) segmentation genes; (c) homeotic genes.

Accepted Answer

(a) Maternal genes in Drosophila play a

Question 7

Describe briefly the relationship between chromatin structure and transcription in eukaryotes.

Accepted Answer

The relationship between chromatin struc

Question 8

In the development of the fly Drosophila, homeotic genes:

Accepted Answer

A)  are transcribed during egg production; their mRNAs lie dormant in the egg until it is fertilized. 
B)  determine the number of body segments that will form. 
C)  are expressed late and determine the detailed structure of each body segment. 
D)  generally have no introns. 
E)  are not translated into proteins. 
A)  are transcribed during egg production; their mRNAs lie dormant in the egg until it is fertilized. 
B)  determine the number of body segments that will form. 
C)  are expressed late and determine the detailed structure of each body segment. 
D)  generally have no introns. 
E)  are not translated into proteins.

Question 9

Which method is NOT a way of regulating the concentration of a protein in a cell?

Accepted Answer

A)  transcriptional regulation 
B)  translational regulation 
C)  degradation of proteins 
D)  posttranslational modification of proteins 
E)  All of these methods are ways of regulating protein concentrations. 
A)  transcriptional regulation 
B)  translational regulation 
C)  degradation of proteins 
D)  posttranslational modification of proteins 
E)  All of these methods are ways of regulating protein concentrations.

Question 10

Which factor is NOT associated with translational regulation?

Accepted Answer

A)  attenuation in the trp operon 
B)  ribosomal protein/mRNA interactions 
C)  riboswitches 
D)  Hfq/OxyS complexes 
E)  All of these are examples of translational regulation. 
A)  attenuation in the trp operon 
B)  ribosomal protein/mRNA interactions 
C)  riboswitches 
D)  Hfq/OxyS complexes 
E)  All of these are examples of translational regulation.

Question 11

Describe three different mechanisms by which riboswitches can modulate mRNA.

Accepted Answer

Riboswitches can modulate mRNA through t

Question 12

What is the primary conclusion of "domain-swapping" experiments with transcriptional regulatory proteins?

Accepted Answer

A) Formation of homo- and hetero-dimers provide combinatorial control of gene expression. 
B) Multiple protein:protein interactions are required to make transcription occur. 
C) Enhancer elements are separate from the promoter site. 
D) Zinc fingers are separate domains involved in DNA binding. 
E) DNA binding elements and protein:protein interaction regions are often found in separate parts of a protein. 
A) Formation of homo- and hetero-dimers provide combinatorial control of gene expression. 
B) Multiple protein:protein interactions are required to make transcription occur. 
C) Enhancer elements are separate from the promoter site. 
D) Zinc fingers are separate domains involved in DNA binding. 
E) DNA binding elements and protein:protein interaction regions are often found in separate parts of a protein.

Question 13

LexA, a protein involved in the SOS response, can be described as both a:

Accepted Answer

A)  negative regulator for transcription and a hydrolase. 
B)  positive regulator for transcription and a hydrolase. 
C)  negative regulator for transcription and an isomerase. 
D)  positive regulator for transcription and an isomerase. 
E)  None of the answers is correct. 
A)  negative regulator for transcription and a hydrolase. 
B)  positive regulator for transcription and a hydrolase. 
C)  negative regulator for transcription and an isomerase. 
D)  positive regulator for transcription and an isomerase. 
E)  None of the answers is correct.

Question 14

Which statement about regulation of the lac operon is TRUE?

Accepted Answer

A)  Glucose in the growth medium decreases the inducibility by lactose. 
B)  Glucose in the growth medium does not affect the inducibility by lactose. 
C)  Glucose in the growth medium increases the inducibility by lactose. 
D)  Its expression is regulated mainly at the level of translation. 
E)  The lac operon is fully induced whenever lactose is present. 
A)  Glucose in the growth medium decreases the inducibility by lactose. 
B)  Glucose in the growth medium does not affect the inducibility by lactose. 
C)  Glucose in the growth medium increases the inducibility by lactose. 
D)  Its expression is regulated mainly at the level of translation. 
E)  The lac operon is fully induced whenever lactose is present.

Question 15

The binding of CRP (cAMP receptor protein of E. coli) to DNA in the lac operon:

Accepted Answer

A)  assists RNA polymerase binding to the lac promoter. 
B)  is inhibited by a high level of cAMP. 
C)  occurs in the lac repressor region. 
D)  occurs only when glucose is present in the growth medium. 
E)  prevents the repressor from binding to the lac operator. 
A)  assists RNA polymerase binding to the lac promoter. 
B)  is inhibited by a high level of cAMP. 
C)  occurs in the lac repressor region. 
D)  occurs only when glucose is present in the growth medium. 
E)  prevents the repressor from binding to the lac operator.

Question 16

Which statement about the transcription attenuation mechanism is TRUE?

Accepted Answer

A)  In some operons (e.g., the his operon), attenuation may be the only regulatory mechanism. 
B)  Sequences of the trp operon leader RNA resemble an operator. 
C)  The leader peptide acts by a mechanism that is similar to that of a repressor protein. 
D)  The leader peptide gene of the trp operon includes no Trp codons. 
E)  The leader peptide is an enzyme that catalyzes transcription attenuation. 
A)  In some operons (e.g., the his operon), attenuation may be the only regulatory mechanism. 
B)  Sequences of the trp operon leader RNA resemble an operator. 
C)  The leader peptide acts by a mechanism that is similar to that of a repressor protein. 
D)  The leader peptide gene of the trp operon includes no Trp codons. 
E)  The leader peptide is an enzyme that catalyzes transcription attenuation.

Question 17

Gene silencing by RNA interference acts by _____ of the target gene.

Accepted Answer

A)  inhibiting transcription 
B)  inhibiting translation 
C)  inhibiting splicing 
D)  degradation of the mRNA 
E)  inhibiting polyadenylyation 
A)  inhibiting transcription 
B)  inhibiting translation 
C)  inhibiting splicing 
D)  degradation of the mRNA 
E)  inhibiting polyadenylyation

Question 18

Describe and contrast positive regulation and negative regulation of gene expression.

Accepted Answer

Gene expression is the process by which

Question 19

In some prokaryotes, some riboswitches act as transcriptional terminators, and they have similarities to rho-independent termination. What structural/sequence features would you predict to find in these riboswitches?

Accepted Answer

Riboswitches are regulatory segments of

Question 20

An example of coordinate control is the down-regulation of ribosomal RNA synthesis in response to amino acid starvation, which will cause synthesis of ribosomal proteins to be limited. What is the CORRECT order of the following events that participate in the signaling process?
1. Binding of stringent factor to the ribosome
2. Formation of the unusual nucleotide ppGpp
3. Formation of the unusual nucleotide pppGpp 4. Binding of uncharged tRNA in the ribosomal A-site

Accepted Answer

A) 	1, 4, 2, 3 
B) 	1, 4, 3, 2 
C) 	4, 1, 2, 3 
D) 	4, 1, 3, 2 
E) 	4, 2, 1, 3 
A) 	1, 4, 2, 3 
B) 	1, 4, 3, 2 
C) 	4, 1, 2, 3 
D) 	4, 1, 3, 2 
E) 	4, 2, 1, 3

Exam 28: Regulation of Gene Expression

A regulon is a(n):

Which class is expressed in the unfertilized egg and is involved in directing the spatial organization of the Drosophila embryo early in development?

Which statement about eukaryotic gene regulation is CORRECT?

Which statement does NOT explain why the lac operon would not be effectively regulated by an attenuation mechanism like the trp operon?

HMG proteins are named because they migrate rapidly in electrophoresis experiments (high mobility group) relative to other DNA binding proteins (particularly histones). What does this tell you about their amino acid composition?

Describe briefly the general role of the protein products of each of the following types of genes in the embryonic development of the Drosophila: (a) maternal genes; (b) segmentation genes; (c) homeotic genes.

Describe briefly the relationship between chromatin structure and transcription in eukaryotes.

In the development of the fly Drosophila, homeotic genes:

Which method is NOT a way of regulating the concentration of a protein in a cell?

Which factor is NOT associated with translational regulation?

Describe three different mechanisms by which riboswitches can modulate mRNA.

What is the primary conclusion of "domain-swapping" experiments with transcriptional regulatory proteins?

LexA, a protein involved in the SOS response, can be described as both a:

Which statement about regulation of the lac operon is TRUE?

The binding of CRP (cAMP receptor protein of E. coli) to DNA in the lac operon:

Which statement about the transcription attenuation mechanism is TRUE?

Gene silencing by RNA interference acts by _____ of the target gene.

Describe and contrast positive regulation and negative regulation of gene expression.

In some prokaryotes, some riboswitches act as transcriptional terminators, and they have similarities to rho-independent termination. What structural/sequence features would you predict to find in these riboswitches?

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

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