Question 1

Which base pair has a potential H-bond acceptor in both the major and minor grooves?

Accepted Answer

A)  A-T 
B)  G-C 
C)  T-A 
D)  C-G 
E)  All of the answers are correct. 
A)  A-T 
B)  G-C 
C)  T-A 
D)  C-G 
E)  All of the answers are correct. E

Question 2

What is the role of HMG proteins in eukaryotic gene regulation?

Accepted Answer

A)  They bind to promoter regions. 
B)  They are architectural regulators. 
C)  They bind to specific enhancer sites. 
D)  They act as coactivators for RNA polymerase. 
E)  They are one type of TATA-binding protein. 
A)  They bind to promoter regions. 
B)  They are architectural regulators. 
C)  They bind to specific enhancer sites. 
D)  They act as coactivators for RNA polymerase. 
E)  They are one type of TATA-binding protein. E

Question 3

What two kinds of regulation exist for the trp 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 B

Question 4

Allolactose binding to the I gene product in the regulation of the lac operon is an example of what?

Accepted Answer

A)  transcriptional activation by reducing repressor binding 
B)  transcriptional inhibition by increasing repressor binding 
C)  transcriptional activation by increasing activator binding 
D)  transcriptional inhibition by decreasing activator binding 
E)  architectural regulation 
A)  transcriptional activation by reducing repressor binding 
B)  transcriptional inhibition by increasing repressor binding 
C)  transcriptional activation by increasing activator binding 
D)  transcriptional inhibition by decreasing activator binding 
E)  architectural regulation

Question 5

Which base pair has a potential H-bond donor in both the major and minor grooves?

Accepted Answer

A)  A-T 
B)  G-C 
C)  T-A 
D)  C-G 
E)  All of the answers are correct. 
A)  A-T 
B)  G-C 
C)  T-A 
D)  C-G 
E)  All of the answers are correct.

Question 6

E. coli cells are placed in a growth medium containing lactose. Indicate how the following circumstances would affect the expression of the lactose operon (increase/decrease/no change).
(a) Addition of high levels of glucose
(b) A Lac repressor mutation that prevents dissociation of Lac repressor from the operator
(c) A mutation that inactivates $\beta$-galactosidase
(d) A mutation that inactivates galactoside permease
(e) A mutation that prevents binding of CRP to its binding site near the lac promoter

Accepted Answer

(a) Addition of high levels of glucose:

Question 7

Which statement is NOT true regarding the regulation of transcription in prokaryotes by RNA?

Accepted Answer

A)  Small RNAs can disrupt local hairpins that prevent ribosome binding. 
B)  Small RNAs require a protein chaperone to facilitate RNA-RNA base pairing. 
C)  Riboswitches are often found in the 5-untranslated region of genes. 
D)  Each riboswitch can bind an assortment of small metabolites. 
E)  Riboswitches can affect either transcription of translation. 
A)  Small RNAs can disrupt local hairpins that prevent ribosome binding. 
B)  Small RNAs require a protein chaperone to facilitate RNA-RNA base pairing. 
C)  Riboswitches are often found in the 5-untranslated region of genes. 
D)  Each riboswitch can bind an assortment of small metabolites. 
E)  Riboswitches can affect either transcription of translation.

Question 8

In E. coli, lactose (allolactose) and tryptophan both bind to repressor proteins as part of regulation of the lac and trp operons, respectively. Outline two differences between the behavior of these compounds and their associated repressor proteins, and describe their effect on the transcription of their associated operons. Why do these differences make physiological sense?

Accepted Answer

One key difference between the behavior

Question 9

What is the role of FljA in S. typhimurium?

Accepted Answer

A)  It is a protein that is used to synthesize flagellin. 
B)  It is involved in promoting recombination of flagellin genes. 
C)  It is a protein that undergoes mutation in order to escape host immune response. 
D)  It is a transcriptional repressor. 
E)  None of the answers is correct. 
A)  It is a protein that is used to synthesize flagellin. 
B)  It is involved in promoting recombination of flagellin genes. 
C)  It is a protein that undergoes mutation in order to escape host immune response. 
D)  It is a transcriptional repressor. 
E)  None of the answers is correct.

Question 10

Which mechanism is NOT a way that galactose metabolism genes are regulated in concert in S. cerevisiae?

Accepted Answer

A) The promoters contain similar sequences. 
B) Many of the mRNA transcripts are polycistronic. 
C) Galactose serves as a coactivator for gene expression. 
D) Upstream activation sequences are similar for the different genes. 
E) All of these mechanisms are used to regulate these genes in concert. 
A) The promoters contain similar sequences. 
B) Many of the mRNA transcripts are polycistronic. 
C) Galactose serves as a coactivator for gene expression. 
D) Upstream activation sequences are similar for the different genes. 
E) All of these mechanisms are used to regulate these genes in concert.

Question 11

Attenuation in the trp operon of E. coli:

Accepted Answer

A)  can adjust transcription of the structural genes upwards when tryptophan is present. 
B)  can fine-tune the transcription of the operon in response to small changes in Trp availability. 
C)  is a mechanism for inhibiting translation of existing (complete) trp mRNAs. 
D)  results from the binding of the Trp repressor to the operator. 
E)  results from the presence of short leader peptides at the 5' end of each structural gene. 
A)  can adjust transcription of the structural genes upwards when tryptophan is present. 
B)  can fine-tune the transcription of the operon in response to small changes in Trp availability. 
C)  is a mechanism for inhibiting translation of existing (complete) trp mRNAs. 
D)  results from the binding of the Trp repressor to the operator. 
E)  results from the presence of short leader peptides at the 5' end of each structural gene.

Question 12

Match each of the operons with the type(s) of regulation present in that operon. Note that a given type can be used more than once, or not at all; also, a given operon may have more than one type of regulation.
Operon
Type or Regulation
(a) lac
(1) Activation
(b) trp
(2) Repression
(c) SOS
(3) Attenuation
(4) DNA rearrangement

Accepted Answer

(a) lac Operon - (1) Activation, (2) Rep

Question 13

DNA-binding transactivating proteins often possess a domain separate from their DNA-binding domains that serve as a docking site for interactions with the transcription complex, coactivators, corepressors, or even chromatin remodeling proteins, to regulate gene transcription. Describe three known kinds of such domains, and provide an example of each.

Accepted Answer

1. Activation domain: An example of an a

Question 14

Which statement is TRUE regarding the cAMP receptor protein (CRP)?

Accepted Answer

A)  This protein is only involved in activating transcription of the lac operon. 
B)  A zinc finger structure binds to the DNA. 
C)  This protein binds as a tetramer to its DNA. 
D)  This protein distorts the DNA structure when it binds. 
E)  Binding of cAMP by CRP increases the value of Kd for the protein:DNA interaction. 
A)  This protein is only involved in activating transcription of the lac operon. 
B)  A zinc finger structure binds to the DNA. 
C)  This protein binds as a tetramer to its DNA. 
D)  This protein distorts the DNA structure when it binds. 
E)  Binding of cAMP by CRP increases the value of Kd for the protein:DNA interaction.

Question 15

Large numbers of micro-RNAs (miRNAs), also known as small temporal RNAs (stRNAs), have now been discovered in higher eukaryotes. Describe their characteristics and general function.

Accepted Answer

Micro-RNAs (miRNAs) are small non-coding

Question 16

Which class of genes is involved in specifying the localization of organs in the Drosophila embryo?

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 17

What statement is FALSE regarding the molecule ppGpp?

Accepted Answer

A)  This molecule is a bacterial second messenger. 
B)  This molecule is produced in response to low concentrations of amino acids. 
C)  This molecule acts as an inhibitor of RNA polymerase. 
D)  This molecule is produced directly from GTP and ATP. 
E)  This molecule will reduce the synthesis of rRNA. 
A)  This molecule is a bacterial second messenger. 
B)  This molecule is produced in response to low concentrations of amino acids. 
C)  This molecule acts as an inhibitor of RNA polymerase. 
D)  This molecule is produced directly from GTP and ATP. 
E)  This molecule will reduce the synthesis of rRNA.

Question 18

Which statement CORRECTLY describes promoters in E. coli?

Accepted Answer

A)  A promoter may be present on either side of a gene or in the middle of it. 
B)  All promoters have the same sequence that is recognized by RNA polymerase holoenzyme. 
C)  Every promoter has a different sequence, with little or no resemblance to other promoters. 
D)  Many promoters are similar and resemble a consensus sequence, which has the highest affinity for RNA polymerase holoenzyme. 
E)  Promoters are not essential for gene transcription, but can increase its rate by two- to three-fold. 
A)  A promoter may be present on either side of a gene or in the middle of it. 
B)  All promoters have the same sequence that is recognized by RNA polymerase holoenzyme. 
C)  Every promoter has a different sequence, with little or no resemblance to other promoters. 
D)  Many promoters are similar and resemble a consensus sequence, which has the highest affinity for RNA polymerase holoenzyme. 
E)  Promoters are not essential for gene transcription, but can increase its rate by two- to three-fold.

Question 19

Promoters for heat shock proteins in E. coli differ from the general consensus sequence. What is the effect of this difference?

Accepted Answer

A)  These genes are never transcribed at high levels. 
B)  These genes are always transcribed at high levels. 
C)  These genes are only expressed in high amounts when an appropriate $\sigma$ subunit is present. 
D)  These genes recognize multiple different $\sigma$subunits. 
E)  These genes are always transcribed at high levels, and they also recognize multiple different $\sigma$ subunits. 
A)  These genes are never transcribed at high levels. 
B)  These genes are always transcribed at high levels. 
C)  These genes are only expressed in high amounts when an appropriate $\sigma$ subunit is present. 
D)  These genes recognize multiple different $\sigma$subunits. 
E)  These genes are always transcribed at high levels, and they also recognize multiple different $\sigma$ subunits.

Question 20

Consider the lac operon of E. coli. When there is neither glucose nor lactose in the growth medium:

Accepted Answer

A)  CRP protein binds to the lac operator. 
B)  CRP protein displaces the Lac repressor from the lac promoter. 
C)  the repressor is bound to the lac operator. 
D)  RNA polymerase binds the lac promoter and transcribes the lac operon. 
E)  the operon is fully induced. 
A)  CRP protein binds to the lac operator. 
B)  CRP protein displaces the Lac repressor from the lac promoter. 
C)  the repressor is bound to the lac operator. 
D)  RNA polymerase binds the lac promoter and transcribes the lac operon. 
E)  the operon is fully induced.

Exam 28: Regulation of Gene Expression

Which base pair has a potential H-bond acceptor in both the major and minor grooves?

What is the role of HMG proteins in eukaryotic gene regulation?

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

Allolactose binding to the I gene product in the regulation of the lac operon is an example of what?

Which base pair has a potential H-bond donor in both the major and minor grooves?

Which statement is NOT true regarding the regulation of transcription in prokaryotes by RNA?

What is the role of FljA in S. typhimurium?

Which mechanism is NOT a way that galactose metabolism genes are regulated in concert in S. cerevisiae?

Attenuation in the trp operon of E. coli:

Which statement is TRUE regarding the cAMP receptor protein (CRP)?

Large numbers of micro-RNAs (miRNAs), also known as small temporal RNAs (stRNAs), have now been discovered in higher eukaryotes. Describe their characteristics and general function.

Which class of genes is involved in specifying the localization of organs in the Drosophila embryo?

What statement is FALSE regarding the molecule ppGpp?

Which statement CORRECTLY describes promoters in E. coli?

Promoters for heat shock proteins in E. coli differ from the general consensus sequence. What is the effect of this difference?

Consider the lac operon of E. coli. When there is neither glucose nor lactose in the growth medium:

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