MMBio EXAM 3 STUDY SET WITH 100% VERIFIED
SOLUTIONS NEW UPDATE!!
Housekeeping gene - ANSWER A gene that must be expressed continually for the cell
to survive
constitutive gene expression - ANSWER The continual expression of a gene
activation - ANSWER The positive regulation of the expression of a gene or genes.
repression - ANSWER A decrease in the expression of a gene in response to a change
in the activity of a regulatory protein.
positive regulation - ANSWER Increased expression of a gene by the binding of an
activator protein.
negative regulation - ANSWER Decreased expression of a gene by the binding of a
repressor protein.
DNA looping - ANSWER The interaction of proteins bound at distant sites on a DNA
molecule so that the intervening DNA forms a loop
enhancer - ANSWER A DNA sequence that facilitates the expression of a given gene;
may be located a few hundred, or even thousand, base pairs away from the gene. In
yeast enhancers are called upstream activator sequences (UASs).
coactivator - ANSWER A protein that stimulates transcription by binding both the RNA
polymerase and an activator or activators, without binding the DNA directly
,corepressor - ANSWER A protein that inhibits transcription by binding both the RNA
polymerase and a repressor or repressors, without binding the DNA directly
insulator - ANSWER A short sequence of DNA that prevents inappropriate
cross-signaling between regulatory elements for different genes. Also called a boundary
element.
operon - ANSWER A unit of genetic expression consisting of one or more related genes
and the operator and promoter sequences that regulate their transcription
regulon - ANSWER A group of genes or operons that are coordinately regulated even
though some, or all, may be spatially distant in the chromosome or genome.
helix-turn-helix motif - ANSWER Supersecondary protein motif consisting of two á
helices separated by a â turn. This motif is crucial to the interaction of many bacterial
regulatory proteins with DNA.
homeodomain motif - ANSWER A conserved 60 amino acid sequence motif in
transcription activators encoded by genes that regulate body pattern development
basic leucine zipper motif - ANSWER A leucine zipper motif in which one side of the
recognition helix has a series of basic residues, which facilitates DNA binding.
basic helix-loop-helix motif - ANSWER A protein secondary structure motif typical of
transcription activators. It consists of two amphipathic á helices joined by a loop of
variable length. Two such motifs dimerize through one pair of á helices. The other á
helices have a series of basic amino acid residues along one side through which they
bind DNA.
zinc finger motif - ANSWER A protein structural motif involved in DNA recognition by
some DNA-binding proteins; characterized by a single atom of zinc coordinated to four
Cys residues or to two His and two Cys residues.
,proteasome - ANSWER Protein complex that degrades damaged and targeted
proteins. Proteins can be targeted for proteolysis by the covalent attachment of
ubiquitin.
transcription factor - ANSWER In eukaryotes, a protein that affects the regulation and
transcription initiation of a gene by binding to a regulatory sequence near or within the
gene and interacting with RNA polymerase and/or other transcription factors.
Q17.1 A housekeeping gene is one that codes for a product that:
A. functions in removing dirt from the cell.
B. is expressed differentially based on the needs of the cell.
C. is expressed at a constitutive level.
D. functions exclusively in cell membrane maintenance. - ANSWER A17.1 C
Q17.2 The sequence of a promoter constitutes the most basic mechanism of
transcription regulation because
A. promoters are always bound by activators.
B. RNA polymerase has differential affinities for different sequences that correlate with
the
efficiency of transcription.
C. promoters are always bound by repressors.
D. the expression levels of different housekeeping genes are always identical. -
ANSWER A17.2 B
Q17.3 Which of the following is least likely to be the result of a mutation in the promoter
of a gene?
A. The level of expression of that gene increases.
B. The level of expression of that gene decreases.
C. The protein sequence of the gene product is altered.
D. The level of expression of that gene remains the same - ANSWER A17.3 C
, Q17.4 A transcription factor that enhances gene expression is called a(n):
A. repressor.
B. enhancer.
C. operator.
D. activator - ANSWER A17.4 D
Q17.5 A transcription factor that reduces gene expression is called a(n):
A. repressor.
B. reducer.
C. operator.
D. activator - ANSWER A17.5 A
Q17.6 Which of the following is NOT an example of a regulatory DNA site?
A. Enhancer
B. Insulator
C. Repressor
D. Operator - ANSWER A17.6 C
Q17.7 Which of the following is the least likely mechanism for reducing the rate of gene
transcription by a repressor?
A. The repressor binds directly to the RNA polymerase to block the closed-to-open
transition at initiation.
B. The repressor induces a conformational change in the polymerase that accelerates
the closed-to-open transition.
C. The binding of the repressor sterically occludes binding of the RNA polymerase to the
promoter.
D. The repressor binds directly to the DNA to stabilize the closed complex over the open
complex. - ANSWER A17.7 B
SOLUTIONS NEW UPDATE!!
Housekeeping gene - ANSWER A gene that must be expressed continually for the cell
to survive
constitutive gene expression - ANSWER The continual expression of a gene
activation - ANSWER The positive regulation of the expression of a gene or genes.
repression - ANSWER A decrease in the expression of a gene in response to a change
in the activity of a regulatory protein.
positive regulation - ANSWER Increased expression of a gene by the binding of an
activator protein.
negative regulation - ANSWER Decreased expression of a gene by the binding of a
repressor protein.
DNA looping - ANSWER The interaction of proteins bound at distant sites on a DNA
molecule so that the intervening DNA forms a loop
enhancer - ANSWER A DNA sequence that facilitates the expression of a given gene;
may be located a few hundred, or even thousand, base pairs away from the gene. In
yeast enhancers are called upstream activator sequences (UASs).
coactivator - ANSWER A protein that stimulates transcription by binding both the RNA
polymerase and an activator or activators, without binding the DNA directly
,corepressor - ANSWER A protein that inhibits transcription by binding both the RNA
polymerase and a repressor or repressors, without binding the DNA directly
insulator - ANSWER A short sequence of DNA that prevents inappropriate
cross-signaling between regulatory elements for different genes. Also called a boundary
element.
operon - ANSWER A unit of genetic expression consisting of one or more related genes
and the operator and promoter sequences that regulate their transcription
regulon - ANSWER A group of genes or operons that are coordinately regulated even
though some, or all, may be spatially distant in the chromosome or genome.
helix-turn-helix motif - ANSWER Supersecondary protein motif consisting of two á
helices separated by a â turn. This motif is crucial to the interaction of many bacterial
regulatory proteins with DNA.
homeodomain motif - ANSWER A conserved 60 amino acid sequence motif in
transcription activators encoded by genes that regulate body pattern development
basic leucine zipper motif - ANSWER A leucine zipper motif in which one side of the
recognition helix has a series of basic residues, which facilitates DNA binding.
basic helix-loop-helix motif - ANSWER A protein secondary structure motif typical of
transcription activators. It consists of two amphipathic á helices joined by a loop of
variable length. Two such motifs dimerize through one pair of á helices. The other á
helices have a series of basic amino acid residues along one side through which they
bind DNA.
zinc finger motif - ANSWER A protein structural motif involved in DNA recognition by
some DNA-binding proteins; characterized by a single atom of zinc coordinated to four
Cys residues or to two His and two Cys residues.
,proteasome - ANSWER Protein complex that degrades damaged and targeted
proteins. Proteins can be targeted for proteolysis by the covalent attachment of
ubiquitin.
transcription factor - ANSWER In eukaryotes, a protein that affects the regulation and
transcription initiation of a gene by binding to a regulatory sequence near or within the
gene and interacting with RNA polymerase and/or other transcription factors.
Q17.1 A housekeeping gene is one that codes for a product that:
A. functions in removing dirt from the cell.
B. is expressed differentially based on the needs of the cell.
C. is expressed at a constitutive level.
D. functions exclusively in cell membrane maintenance. - ANSWER A17.1 C
Q17.2 The sequence of a promoter constitutes the most basic mechanism of
transcription regulation because
A. promoters are always bound by activators.
B. RNA polymerase has differential affinities for different sequences that correlate with
the
efficiency of transcription.
C. promoters are always bound by repressors.
D. the expression levels of different housekeeping genes are always identical. -
ANSWER A17.2 B
Q17.3 Which of the following is least likely to be the result of a mutation in the promoter
of a gene?
A. The level of expression of that gene increases.
B. The level of expression of that gene decreases.
C. The protein sequence of the gene product is altered.
D. The level of expression of that gene remains the same - ANSWER A17.3 C
, Q17.4 A transcription factor that enhances gene expression is called a(n):
A. repressor.
B. enhancer.
C. operator.
D. activator - ANSWER A17.4 D
Q17.5 A transcription factor that reduces gene expression is called a(n):
A. repressor.
B. reducer.
C. operator.
D. activator - ANSWER A17.5 A
Q17.6 Which of the following is NOT an example of a regulatory DNA site?
A. Enhancer
B. Insulator
C. Repressor
D. Operator - ANSWER A17.6 C
Q17.7 Which of the following is the least likely mechanism for reducing the rate of gene
transcription by a repressor?
A. The repressor binds directly to the RNA polymerase to block the closed-to-open
transition at initiation.
B. The repressor induces a conformational change in the polymerase that accelerates
the closed-to-open transition.
C. The binding of the repressor sterically occludes binding of the RNA polymerase to the
promoter.
D. The repressor binds directly to the DNA to stabilize the closed complex over the open
complex. - ANSWER A17.7 B
