Question 1

The λ repressor can act as a transcriptional activator as well as a repressor.

Accepted Answer

A) True 
 B)False  True

Question 2

miRNAs are used in gene regulation to:

Accepted Answer

A)  block translation. 
B)  target mRNA for degradation. 
C)  cause ribosomes to stall. 
D)  promote degradation of polyA tails. 
E)  all of the above. 
A)  block translation. 
B)  target mRNA for degradation. 
C)  cause ribosomes to stall. 
D)  promote degradation of polyA tails. 
E)  all of the above. E

Question 3

Which of the following BEST describes attenuation of the trp operon?

Accepted Answer

A)  The ribosome will stall at adjacent trp codons if tryptophan levels in the cell are low. 
B)  High levels of tryptophan result in continued translation by the ribosome. 
C)  A transcription termination sequence forms in the leader mRNA because the ribosome reaches a translation stop codon if tryptophan levels are high. 
D)  The structural genes are not expressed if tryptophan levels in the cell are high. 
E)  Regulation of trp operon expression by transcriptional repression by the trp repressor when tryptophan levels in the cell are high. 
A)  The ribosome will stall at adjacent trp codons if tryptophan levels in the cell are low. 
B)  High levels of tryptophan result in continued translation by the ribosome. 
C)  A transcription termination sequence forms in the leader mRNA because the ribosome reaches a translation stop codon if tryptophan levels are high. 
D)  The structural genes are not expressed if tryptophan levels in the cell are high. 
E)  Regulation of trp operon expression by transcriptional repression by the trp repressor when tryptophan levels in the cell are high. C

Question 4

ATPase domains of chromatin remodelers associated with transcriptionally active chromatin can contain a bromodomain that interacts specifically with ________ lysines or a chromodomain that interacts specifically with ________ histones.

Accepted Answer

acetylated

Question 5

RNA interference can be a mechanism of defense against viral infection as well as for regulation of gene expression.

Accepted Answer

A) True 
 B)False

Question 6

________ of specific RNA nucleotides in a process known as RNA editing is a mechanism of altering the protein product encoded by some genes in mammals.

Accepted Answer

The answer of ________ of specific RNA nucleotides in a...

Question 7

All chromatin remodelling complexes are associated with activation of transcription.

Accepted Answer

A) True 
 B)False

Question 8

Conformational changes in the cAMP receptor protein upon binding to cAMP trigger ________ of the lac operon in the presence of lactose.

Accepted Answer

The answer of Conformational changes in the cAMP receptor protein...

Question 9

The helix-turn-helix is a common protein motif that is able to interact with DNA in the major grooves by both electrostatic and specific interactions between amino acids of the helix and the bases of the DNA.

Accepted Answer

A) True 
 B)False

Question 10

Nucleosome remodeling complexes use ________ to drive changes in chromatin structure.

Accepted Answer

The answer of Nucleosome remodeling complexes use ________ to drive...

Question 11

A partial diploid containing a wild type allele for lacI and a lacI mutant that was unable to bind the inducer would:

Accepted Answer

A)  always show low levels of β-galactosidase gene expression. 
B)  show normal induction in the presence of an inducer. 
C)  express β-galactosidase at all times. 
D)  only show normal induction in the presence of an inducer in the absence of glucose. 
E)  show induction in the presence of an inducer in the presence of glucose. 
A)  always show low levels of β-galactosidase gene expression. 
B)  show normal induction in the presence of an inducer. 
C)  express β-galactosidase at all times. 
D)  only show normal induction in the presence of an inducer in the absence of glucose. 
E)  show induction in the presence of an inducer in the presence of glucose.

Question 12

Which of the following BEST describes the SOS response?

Accepted Answer

A)  DNA damage by UV light causes a λ lysogen to be induced to the lytic life cycle. 
B)  It is an error prone DNA repair system. 
C)  Activation of RecA by sensing DNA damage and single-stranded DNA. 
D)  Coordinated activation of a set of unlinked genes whose protein products will collectively help the cell to respond to environmental damage. 
E)  Transcriptional depression by proteolytic cleavage of the LexA repressor. 
A)  DNA damage by UV light causes a λ lysogen to be induced to the lytic life cycle. 
B)  It is an error prone DNA repair system. 
C)  Activation of RecA by sensing DNA damage and single-stranded DNA. 
D)  Coordinated activation of a set of unlinked genes whose protein products will collectively help the cell to respond to environmental damage. 
E)  Transcriptional depression by proteolytic cleavage of the LexA repressor.

Question 13

DNA methylation in eukaryotes:

Accepted Answer

A)  is part of the epigenetic process. 
B)  occurs only on cytosine residues. 
C)  is maintained by specific DNA methyl transferases. 
D)  is inhibited by 5'-azacytidine. 
E)  all of the above. 
A)  is part of the epigenetic process. 
B)  occurs only on cytosine residues. 
C)  is maintained by specific DNA methyl transferases. 
D)  is inhibited by 5'-azacytidine. 
E)  all of the above.

Question 14

________ are alternative mRNA structures that are produced by binding of a ________ which is often a product of a specific metabolic pathway.

Accepted Answer

Riboswitch

Question 15

The greater complexity of humans compared to worms and flies is due to:

Accepted Answer

A)  a greater number of genes. 
B)  higher levels of alternative splicing. 
C)  a much greater number of transcription factors. 
D)  chromatin structure. 
E)  combinatorial regulation by a greater number of transcription factors. 
A)  a greater number of genes. 
B)  higher levels of alternative splicing. 
C)  a much greater number of transcription factors. 
D)  chromatin structure. 
E)  combinatorial regulation by a greater number of transcription factors.

Question 16

Which of the following BEST describes transcriptional regulation of the lac operon in E. coli?

Accepted Answer

A)  On in the presence of lactose 
B)  On in the presence of lactose and presence of glucose 
C)  Off in the presence of glucose 
D)  On in the absence of lactose and presence of glucose 
E)  On in the presence of lactose and absence of glucose 
A)  On in the presence of lactose 
B)  On in the presence of lactose and presence of glucose 
C)  Off in the presence of glucose 
D)  On in the absence of lactose and presence of glucose 
E)  On in the presence of lactose and absence of glucose

Question 17

Which of the following is INCORRECT when considering the lac repressor?

Accepted Answer

A)  It is tetramer of two dimers. 
B)  Binding to the operator site is cooperative. 
C)  Binding of each dimer is to different regions of the operator. 
D)  Binding of inducer forces the DNA-binding helices apart so they cannot contact the DNA-binding sites. 
E)  It is an allosteric protein. 
A)  It is tetramer of two dimers. 
B)  Binding to the operator site is cooperative. 
C)  Binding of each dimer is to different regions of the operator. 
D)  Binding of inducer forces the DNA-binding helices apart so they cannot contact the DNA-binding sites. 
E)  It is an allosteric protein.

Question 18

________ mutants of the lac operon express β-galactosidase at high levels in the absence of an inducer, while ________ mutants of the lac operon express only very low levels of β-galactosidase even in the presence of inducer.

Accepted Answer

Constituti

Question 19

Which of the following BEST describes catabolite repression of the lac operon?

Accepted Answer

A)  The operon is transcriptionally inactive in the absence of lactose. 
B)  The operon is transcriptionally inactivated by a repressor protein, which binds to glucose. 
C)  The operon is transcriptionally active when an activator protein binds to the promoter in the absence of glucose. 
D)  Glucose is the preferred energy source for E. coli. 
E)  The operon is repressed by its protein products. 
A)  The operon is transcriptionally inactive in the absence of lactose. 
B)  The operon is transcriptionally inactivated by a repressor protein, which binds to glucose. 
C)  The operon is transcriptionally active when an activator protein binds to the promoter in the absence of glucose. 
D)  Glucose is the preferred energy source for E. coli. 
E)  The operon is repressed by its protein products.

Question 20

The λ repressor is inactivated by proteolytic cleavage stimulated by the ________ protein.

Accepted Answer

The answer of The λ repressor is inactivated by proteolytic...

Exam 26: Regulation of Gene Expression

The λ repressor can act as a transcriptional activator as well as a repressor.

miRNAs are used in gene regulation to:

Which of the following BEST describes attenuation of the trp operon?

ATPase domains of chromatin remodelers associated with transcriptionally active chromatin can contain a bromodomain that interacts specifically with ________ lysines or a chromodomain that interacts specifically with ________ histones.

RNA interference can be a mechanism of defense against viral infection as well as for regulation of gene expression.

________ of specific RNA nucleotides in a process known as RNA editing is a mechanism of altering the protein product encoded by some genes in mammals.

All chromatin remodelling complexes are associated with activation of transcription.

Conformational changes in the cAMP receptor protein upon binding to cAMP trigger ________ of the lac operon in the presence of lactose.

The helix-turn-helix is a common protein motif that is able to interact with DNA in the major grooves by both electrostatic and specific interactions between amino acids of the helix and the bases of the DNA.

Nucleosome remodeling complexes use ________ to drive changes in chromatin structure.

A partial diploid containing a wild type allele for lacI and a lacI mutant that was unable to bind the inducer would:

Which of the following BEST describes the SOS response?

DNA methylation in eukaryotes:

________ are alternative mRNA structures that are produced by binding of a ________ which is often a product of a specific metabolic pathway.

The greater complexity of humans compared to worms and flies is due to:

Which of the following BEST describes transcriptional regulation of the lac operon in E. coli?

Which of the following is INCORRECT when considering the lac repressor?

________ mutants of the lac operon express β-galactosidase at high levels in the absence of an inducer, while ________ mutants of the lac operon express only very low levels of β-galactosidase even in the presence of inducer.

Which of the following BEST describes catabolite repression of the lac operon?

The λ repressor is inactivated by proteolytic cleavage stimulated by the ________ protein.

Biochemistry and the Language of Chemistry

The Chemical Foundation of Life: Weak Interactions in an Aqueous Environment

The Energetics of Life

Nucleic Acids

Introduction to Proteins: the Primary Level of Protein Structure

The Three-Dimensional Structure of Proteins

Protein Function and Evolution

Enzymes: Biological Catalysts

Carbohydrates: Sugars, Saccharides, Glycans

Lipids, Membranes, and Cellular Transport

Chemical Logic of Metabolism

Carbohydrate Metabolism: Glycolysis, Gluconeogenesis, Glycogen Metabolism, and the Pentose Phosphate Pathway

The Citric Acid Cycle

Electron Transport, Oxidative Phosphorylation, and Oxygen Metabolism

Photosynthesis

Lipid Metabolism

Interorgan and Intracellular Coordination of Energy Metabolism in Vertebrates

Amino Acid and Nitrogen Metabolism

Nucleotide Metabolism

Mechanisms of Signal Transduction

Genes, Genomes, and Chromosomes

DNA Replication

DNA Repair, Recombination, and Rearrangement

Transcription and Post-Transcriptional Processing

Information Decoding: Translation and Post-Translational Protein Processing

Filters

ATPase domains of chromatin remodelers associated with transcriptionally active chromatin can contain a bromodomain that interacts specifically with lysines or a chromodomain that interacts specifically with histones.

are alternative mRNA structures that are produced by binding of a which is often a product of a specific metabolic pathway.

mutants of the lac operon express β-galactosidase at high levels in the absence of an inducer, while mutants of the lac operon express only very low levels of β-galactosidase even in the presence of inducer.