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Gene Regulation Practice Questions
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Which of the following is a protein produced by a regulatory gene?
A) inducer
B) operon
C) promoter
D) repressor
1)
2) Which of the following, when taken up by a cell, binds to a repressor so that the repressor no longer
binds to the operator?
A) repressor
B) corepressor
C) promoter
D) inducer
2)
3) A mutation that inactivates a regulatory gene of a repressible operon in an E. coli cell would result
in _____.
A) complete inhibition of transcription of the structural gene controlled by that regulator
B) irreversible binding of the repressor to the operator
C) continuous transcription of the structural gene controlled by that regulator
D) continuous translation of the mRNA because of alteration of its structure
3)
4) Altering patterns of gene expression in prokaryotes would most likely serve an organism's survival
by _____.
A) allowing each gene to be expressed an equal number of times
B) allowing environmental changes to alter a prokaryote's genome
C) allowing an organism to adjust to changes in environmental conditions
D) organizing gene expression, so that genes are expressed in a given order
4)
5) There is a mutation in the repressor that results in a molecule known as a super-repressor because
it represses the lac operon permanently. Which of these would characterize such a mutant?
A) It makes a repressor that binds CAP.
B) It cannot bind to the operator.
C) It cannot make a functional repressor.
D) It cannot bind to the inducer.
5)
6) What would occur if the repressor of an inducible operon were mutated so that it could not bind
the operator?
A) reduced transcription of the operon's genes
B) overproduction of catabolite activator protein (CAP)
C) irreversible binding of the repressor to the promoter
D) continuous transcription of the operon's genes
6)
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7) The trp repressor blocks transcription of the trp operon when the repressor _____.
A) is not bound to tryptophan
B) binds to the inducer
C) is not bound to the operator
D) binds to tryptophan
7)
8) CAP is said to be responsible for positive regulation of the lac operon because _____.
A) CAP prevents binding of the repressor to the operator
B) CAP binds cAMP
C) CAP bound to the CAP-binding site increases the frequency of transcription initiation
D) CAP binds to the CAP-binding site
8)
9) The primary difference between enhancers and promoter-proximal elements is that enhancers
_____.
A) enhance transcription; promoter-proximal elements inhibit transcription
B) are transcription factors; promoter-proximal elements are DNA sequences
C) are at considerable distances from the promoter; promoter-proximal elements are close to the
promoter
D) are DNA sequences; promoter-proximal elements are proteins
9)
10) Gene expression is often assayed by measuring the level of mRNA produced from a gene. If one is
interested in knowing the amount of a final active gene product, a potential problem of this method
is that it ignores the possibility of _____.
A) chromatin condensation control
B) alternative splicing
C) transcriptional control
D) translational control
10)
11) One way to detect alternative splicing of transcripts from a given gene is to _____.
A) compare the sequences of different mRNAs made from the given gene
B) compare the sequences of different primary transcripts made from the given gene
C) measure the relative rates of transcription of the given gene compared to that of a gene
known to be constitutively spliced
D) compare the DNA sequence of the given gene to that of a similar gene in a related organism
11)
12) Which of the following mechanisms is (are) used to coordinate the expression of multiple, related
genes in eukaryotic cells?
A) The genes share a single common enhancer, which allows appropriate activators to turn on
their transcription at the same time.
B) The genes are organized into a large operon, allowing them to be coordinately controlled as a
single unit.
C) A single repressor is able to turn off several related genes.
D) Environmental signals enter the cell and bind directly to promoters.
12)
13) DNA methylation and histone acetylation are examples of _____.
A) translocation
B) genetic mutation
C) epigenetic phenomena
D) chromosomal rearrangements
13)
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14) Steroid hormones produce their effects in cells by _____.
A) activating key enzymes in metabolic pathways
B) binding to intracellular receptors and promoting transcription of specific genes
C) activating translation of certain mRNAs
D) promoting the degradation of specific mRNAs
14)
Use this information to answer the question(s) below.
A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells
in culture.
15) In one set of experiments she succeeded in increasing acetlylation of histone tails. Which of the
following results would she most likely see?
A) decreased chromatin condensation
B) decreased binding of transcription factors
C) increased chromatin condensation
D) inactivation of the selected genes
15)
16) Which method is utilized by eukaryotes to control their gene expression that is NOT used in
bacteria?
A) control of RNA splicing
B) control of chromatin remodeling
C) control of both RNA splicing and chromatin remodeling
D) transcriptional control
16)
17) At the beginning of this century there was a general announcement regarding the sequencing of the
human genome and the genomes of many other multicellular eukaryotes. Many people were
surprised that the number of protein-coding sequences was much smaller than they had expected.
Which of the following could account for much of the DNA that is not coding for proteins?
A) non-protein-coding DNA that is transcribed into several kinds of small RNAs with biological
function
B) non-protein-coding DNA that serves as binding sites for reverse transcriptase
C) DNA that is translated directly without being transcribed
D) DNA that consists of histone coding sequences
17)
18) The fact that plants can be cloned from somatic cells demonstrates that _____.
A) genes are lost during differentiation
B) differentiation does not occur in plants
C) the differentiated state is normally very unstable
D) differentiated cells retain all the genes of the zygote
18)
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19) In this drawing of the lac operon, which molecule is an inactive repressor?
19)
A) molecule A
B) molecule B
C) molecule C
D) molecule D
20) Which structure in this figure shows one complete nucleosome?
A) structure A
B) structure B
C) structure C
D) structure D
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20)
21) The figure below shows a normal cell transduction pathway. If the receptor wasn't there, which of
the following is the most likely outcome?
A) Cell division will occur normally.
B) Cell division will be increased.
C) Cell division will be decreased.
D) Cell division will not occur at all.
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21)
Answer Key
Testname: CH18PRACTICEQUESTIONS
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D
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