Deck 16: Control of Gene Expression

Question 1

The most common form of control of gene expression in both the prokaryotic and eukaryotic organisms is

A)RNA processing control.
B)translational control.
C)protein phosphorylation control.
D)transcriptional control.
E)mRNA degradation control.

Answer 1

D

Question 2

Enhancers are the binding sites for the

A)promotors of DNA synthesis.
B)suppressor factors.
C)co-activation factors.
D)mediator factors.
E)specific transcription factors.

Answer 2

E

Question 3

A nucleosome contains ____ histones within its core.

A)2
B)4
C)6
D)8
E)64

Answer 3

D

Question 4

Small RNAs,once thought to be of no importance in gene expression contain

A)between 21 to 28 nucleotides.
B)exactly 64 nucleotides.
C)between 15 and 20 codons.
D)between 21 and 64 codons.

Question 5

The most common form of regulation in bacteria and eukaryotes is

A)transcriptional control.
B)translational control.
C)promotor control.
D)repressor control.
E)operator control.

Question 6

RNA polymerase binds to a site on DNA called the

A)operator.
B)repressor.
C)footprint.
D)promoter.
E)operon.

Question 7

Transcriptional control-proteins increase the rate of transcription by binding to

A)mRNA sequences within the DNA.
B)tRNA sequences within the DNA.
C)operator sequences within the DNA.
D)promotor sequences within the DNA.
E)enhancer sequences within the DNA.

Question 8

A bacterial cell takes advantage of changing __________ conditions through control of gene expression.

A)internal
B)protein
C)environmental
D)genetic

Question 9

In multicellular organisms,gene _________ is critical for directing development and maintaining homeostasis.

A)expression
B)duplication
C)deletion
D)regulation

Question 10

Vertebrate cells apparently possess a protein that by binding to clusters of 5-methylcytosine ensures that the bound gene will stay in the "off" position.This control on the role of gene regulation is a result of

A)translation.
B)enhancer expression.
C)methylation.
D)promotor expression.
E)operator suppression.

Question 11

Regulatory proteins shut off transcription by binding to a site immediately in front of the promoter and often even overlapping the promotor.This site is referred to as the

A)suppressor site.
B)operator site.
C)repressor site.
D)regulatory site.
E)transcriptional control sitE.

Question 12

Histones are tightly packed into ______,which are located within the DNA.

A)operons
B)nucleosomes
C)clusters of proteins
D)repressor genes
E)facilitators sites

Question 13

DNA methylation,adding a methyl group to DNA nucleotides,in vertebrates ensures that

A)the gene functions without interruption.
B)no errors will be made during transcription.
C)the nucleosome will quickly form,which assists in mRNA formation.
D)once that gene is transcribed,the mRNA is saved and used over and over again.
E)once a gene is turned off,it will remain off.

Question 14

Which of the following is not true about control of gene expression?

A)In bacteria it allows them to adopt to changing environments.
B)In multicellular organisms it is critical for development.
C)In bacteria it allows them to replicate without control.
D)In multicellular organisms it allows them to maintain homeostasis.
E)In multicellular organisms it allows them to function as a wholE.

Question 15

In __________ organisms,the primary function of a gene in a cell is to participate in regulating the body as a whole and not to responding to the cell's immediate environment.

A)multicellular
B)diploid
C)bacterial
D)prokaryotic

Question 16

Which of the following is the hallmark of multicellular organisms?

A)grow and divide rapidly
B)cells adjust quickly to outside environment
C)homeostasis
D)quickly synthesize amount and type of enzymes according to available nutrients
E)respond by gene action to oxygen availability

Question 17

The maintenance of a constant environment in a cell is called ___________.

A)active transport
B)homeostasis
C)gene expression
D)translation

Question 18

All regulatory proteins have common DNA binding motifs,which are particular bends in their protein chains that permit them to interlock with the

A)minor groove of the DNA helix.
B)major groove of the DNA helix.
C)outside groove of the DNA helix.
D)inside groove of the DNA helix.
E)hydrogen bonding groove of the DNA helix.

Question 19

Eukaryotic cell mRNA transcripts tend to be very ______ and can remain in the cell for hours.

A)stable
B)long
C)isolated
D)analogous

Question 20

The basic tool of genetic regulation is the ability of certain proteins to bind to specific

A)regulatory RNA sequences.
B)regulatory DNA sequences.
C)repressor parts of the gene.
D)promoter parts of the gene.
E)enzymes of the cell.

Question 21

In gene regulation,negative control is exerted by a(n)

A)activator.
B)operon.
C)promoter.
D)regulator.
E)repressor.

Question 22

A protein that regulates transcription by binding to the operator.

A)operon
B)repressor
C)promoter
D)operator
E)CAP

Question 23

The lac regulatory system is important to bacteria because the sugar lactose

A)cannot be made by bacteria unless the genes are turned on.
B)is the most common source of food;enzymes are needed all the time.
C)is only rarely available;producing enzymes all the time is costly.
D)is incorporated into the nucleic acid of the bacteria.
E)switches the system off and on whether lactose is present or not.

Question 24

Although the specific mechanism of RNA interference has not been fully defined,it involves

A)double stranded RNA interference with mRNA.
B)double stranded RNA interference with DNA.
C)double stranded DNA interference with mRNA.
D)double stranded mRNA interference with DNA.

Question 25

Certain proteins can bind to specific DNA regulatory sequences by

A)entering the major groove of the DNA and reading the nucleotide base pairs.
B)entering the minor groove of the DNA and reading the nucleotide base pairs.
C)entering the major groove of RNA and reading the nucleotide base pairs.
D)entering DNA's major groove by using DNA polymerase and reading the nucleotide base pairs.
E)entering DNA's minor groove by using DNA polymerase and reading the nucleotide base pairs.

Question 26

In gene regulation,a gene is "turned on" by a(n)

A)activator.
B)stimulator.
C)promoter.
D)regulator.
E)repressor.

Question 27

The most common DNA-binding motif is the

A)non-helical zipper.
B)leucine zipper.
C)zinc finger.
D)homeodomain.
E)helix-turn-helix.

Question 28

All of the following are examples of shapes in regulatory proteins which are used to bind to DNA except the

A)zinc finger.
B)TATA box.
C)helix-turn-helix.
D)homeodomain.
E)leucine zipper.

Question 29

Small RNAs can regulate gene expression.One type,called micro RNA (miRNA),acts by binding directly to

A)mRNA to prevent translation.
B)tRNA to prevent transcription.
C)mRNA to prevent transcription.
D)tRNA to prevent translation.

Question 30

In eukaryotes,specific transcription factors have two distinct domains:

A)a DNA-binding domain and a RNA-binding domain.
B)a DNA-binding domain and an activation domain.
C)a DNA-binding domain and a repressor domain.
D)a DNA-binding domain and an enhancer domain.
E)a DNA-binding domain and an operator domain.

Question 31

Regulatory proteins can identify specific sequences on the DNA double helix without unwinding the helix.This is accomplished by

A)inserting DNA promoters into either the major groove or the minor groove of the double helix where the edges of the nitrogen bases protrude.
B)inserting DNA-binding motifs into the minor groove of the double helix where the edges of the nitrogen bases protrude.
C)inserting DNA polymerase into the major groove of the double helix where the edges of the nitrogen bases protrude.
D)inserting RNA polymerase into the major groove of the double helix where the edges of the nitrogen bases protrude.
E)inserting DNA-binding motifs into the major groove of the double helix where the edges of the nitrogen bases protrudE.

Question 32

Which of the following must happen for transcription to be initiated?

A)DNA polymerase must have access to the DNA double helix and also must be capable of binding to the gene's promoter.
B)RNA polymerase must have access to the DNA double helix and also must be capable of binding to the gene's promoter.
C)DNA polymerase must have access to the RNA and also must be capable of binding to the gene's promoter.
D)DNA ligase must have access to the DNA double helix and also must be capable of binding to the gene's promoter.
E)DNA kinase must have access to the DNA double helix and also must be capable of binding to the gene's promoter.

Question 33

The CAP molecule can attach to the CAP binding site only when the

A)CAP molecule is bound to lactose.
B)CAP molecule is bound to tryptophan.
C)CAP molecule is bound to ATP.
D)CAP molecule is bound to cAMP.
E)CAP molecule is activated by homeodomain DNA binding motif.

Question 34

A bacterial gene regulatory system is likely to have all of the following except

A)a coding sequence.
B)an operator.
C)a promoter.
D)one or more introns.
E)a ribosome recognition sitE.

Question 35

Proteins that bind to regulatory sequences have shapes that fit into the

A)promoter.
B)operator.
C)operon.
D)minor groove of DNA.
E)major groove of DNA.

Question 36

One of the DNA-binding motifs that contains a nearly identical sequence of 60 amino acids in many eukaryotic organisms is known as the

A)non-helical zipper.
B)leucine zipper.
C)zinc finger.
D)homeodomain.
E)helix-turn-helix.

Question 37

A protein that initiates the transcription of genes which allow the use of non-glucose molecules.

A)operon
B)repressor
C)promoter
D)operator
E)CAP

Question 38

The DNA-binding proteins of almost all regulatory proteins employ one of a small set of shapes that enable them to fit into the major groove of DNA.These shapes are called

A)structural motifs.
B)DNA prints.
C)operons.
D)repressors.
E)transcriptional domains.

Question 39

Which of the following statements regarding primary transcripts in eukaryotes is correct?

A)The primary transcript is composed of RNA polymerase and associated histones.
B)The primary transcript has the exons removed and the introns retained for translation.
C)The primary transcript is a faithful copy of the entire gene including exons and introns.
D)The primary transcript is a faithful copy of the gene,but the introns have been removeD.
E)The primary transcript is a faithful copy,but the exons have been removed.

Question 40

Eukaryotic organisms

A)have their transcription occurring in the cytoplasm and translation in the nucleus.
B)have their transcription occurring in the nucleus and translation in the cytoplasm.
C)have only operons to assist in gene expression.
D)carry out protein synthesis only in the presence of the cAMP molecule.
E)use the leucine zipper primarily for the production of the amino acid tryptophan.

Question 41

In eukaryotes,the binding of TFIID is followed by the binding of a number of other general transcription factors.Which of the following lists the correct order of binding of these factors?

A)TFIIA,TFIIB,TFIIE,TFIIF,TFIIH
B)TFIIE,TFIIF,TFIIA,TFIIB,TFIIH
C)TFIIF,TFIIH,TFIIB,TFIIE,TFIIA
D)TFIIE,TFIIB,TFIIA,TFIIH,TFIIF

Question 42

A site of negative genetic regulation;binding by repressor blocks transcription.

A)operon
B)repressor
C)promoter
D)operator
E)CAP

Question 43

Elucidation of the histone code might

A)allow us to turn specific genes on or off.
B)allow the determination of nucleosome composition.
C)lead to chromatin remodeling.
D)allow us to control translation.

Question 44

The enzyme $\beta$ -galactosidase acts on lactose to form galactose.In turn,the presence of galactose leads to expression of the enzymes responsible for the metabolism of galactose.In this case,lactose is serving as a carbon source and as a(n)

A)inducer.
B)repressor.
C)effector.
D)operon.

Question 45

You are working to identify enhancer regions of a particular gene.You should look

A)immediately upstream of the promoter.
B)immediately downstream of the promoter.
C)primarily upstream of the promoter;distance from the promoter does not matter.
D)primarily downstream of the promoter;distance from the promoter does not matter.

Question 46

Mutations in the -35 region of the trp operon would

A)interfere with RNA polymerase binding to the promotor.
B)prevent the repressor from binding to the operator.
C)result in depression of the trp operon.
D)enable the trp operon to be expressed in the absence of tryptophan.

Question 47

You are performing a mutagenesis screen to isolate mutations in Drosophila.While looking through a batch of mutagenized flies,you find a fly in which its antenna had been transformed to a pair of extra legs.You surmise that this fly must have a mutation in regulatory protein that contains which type of DNA-binding motif?

A)helix-turn-helix
B)homeodomain
C)zinc finger
D)leucine zipper

Question 48

You are studying the regulation of a prokaryotic operon.Experimental results suggest that the operon is governed by negative control.Based on this information,you conclude that

A)the operon is ON in the absence of its regulatory protein.
B)the operon is OFF in the absence of its regulatory protein.
C)the presence of an inducer will always cause a repressor to bind the operator.
D)the presence of an inducer will always prevent a repressor from binding the operator.

Question 49

The main form of glucose repression of the lac operon is

A)induction.
B)repression.
C)inducer exclusion.
D)the CAP/cAMP system.

Question 50

Your research project involves the characterization of a recently identified transcription factor.As part of your project,you want to determine if this transcription factor binds directly to any of the general transcription factors.Unfortunately,however,you are having trouble expressing and purifying the full length protein.Which of the following options may help you achieve your research goal?

A)Since transcription domains cannot be separated,you will need to abandon this experiment and try a vastly different approach to your question.
B)Express large amounts of the general transcription factors.
C)Since transcription domains can be separated,try to express and purify only the DNA-binding domain.
D)Since transcription domains can be separated,try to express and purify only the activation domain.

Question 51

A site at the 5' end of a gene to which RNA polymerase attaches to initiate transcription.

A)operon
B)repressor
C)promoter
D)operator
E)CAP

Question 52

The lactose analog isopropyl- $\beta$ -D-thio-galactoside (IPTG)is often used to regulate gene expression systems in bacteria.IPTG does not act as a substrate for $\beta$ -galactosidase,but can bind to,and inactivate,repressor.In this case,IPTG serves as a(n)

A)inducer.
B)repressor.
C)effector.
D)operon.

Question 53

A cluster of functionally-related genes encoded into a mRNA molecule;a mode of prokaryotic gene regulating unit.

A)operon
B)repressor
C)promoter
D)operator
E)CAP

Question 54

The TFIID complex is formed by

A)TATA-binding protein TBP and TAFs.
B)TATA-binding protein TBP,TAFs and RNA pol II.
C)TAFs and the core promoter.
D)TATA-binding protein and activators.

Question 55

Which of the following statements regarding the eukaryotic transcription initiation complex is false?

A)Initiation of transcription of virtually all genes transcribed by RNA pol II require the same suite of general factors.
B)The transcription initiation transcription complex is responsible for unregulated transcription levels.
C)The transcription initiation complex can interact with activators through DNA looping.
D)Basal factors remain associated with RNA pol II after positioning RNA pol II at the start site.

Question 56

If you were able to look very closely at a portion of DNA and find methylated histones,you would

A)be mistaken since only DNA can be methylated,not histones.
B)be looking at a region of active chromatin.
C)be looking at a region of inactive chromatin.
D)be looking at a chromatin remodeling complex.

Question 57

Which of the following statements regarding control of the lac operon and lactose utilization in bacteria is false?

A)The lac operon will not be induced in the presence of both glucose and lactose.
B)Control of the lac operon is negative,mediated by a repressor.
C)The lac operon controls the expression of three downstream genes.
D)Bacteria preferentially utilize lactose as a carbon source.

Question 58

The p300/CBP (CREB-binding protein)coactivator proteins are histone acetyltransferases that help regulate the transcription of many genes.Based on this information,these proteins are involved in

A)DNA acetylation.
B)chromatin remodeling.
C)recruitment of RNA pol II.
D)formation of the transcription initiation complex.

Question 59

The progesterone receptor (PR)is a steroid hormone receptor and transcription factor.The protein SRC-1,which does not bind DNA by itself,can bind to PR and increase expression of genes regulated by PR.Based on this information,SRC-1 is a(n)

A)coactivator.
B)inducer.
C)basal transcription factor.
D)specific transcription factor.

Question 60

DNA methylation is the only known natural modification of DNA.It affects

A)adenine bases.
B)guanine bases.
C)cytosine bases.
D)thymine bases.

Question 61

Which of the following statements regarding the ubiquitin-proteosome pathway is false?

A)This pathway is used to regulate expression of a number of cell surface receptors.
B)When proteins are destroyed by the proteosome,the ubiquitin moiety is not destroyed,but rather cleaved off and reused.
C)Ubiquitin ligase adds ubiquitin residues to targeted proteins in a stepwise fashion.
D)Ubiquitination of a targeted protein requires only one molecule of ATP.

Question 62

Production of the iron-storing protein ferritin is regulated by aconitase,which binds to a 30-nucleotide sequence at the beginning of the ferritin mRNA and interferes with ribosome binding.Aconitase is a

A)transcription repressor protein.
B)translation repressor protein.
C)RNA interference protein.
D)translation initiation protein.

Question 63

What is the difference between a gene that is derepressed and one that is induced?

A)A gene that is derepressed is turned on because a repressor molecule is absent.By comparison,a gene that is induced is turned on because an inducer molecule is present.
B)A gene that is derepressed is turned on because an inducer molecule is present.By comparison,a gene that is induced is turned on because a repressor molecule is absent.
C)There is no functional difference between a gene that is derepressed and one that is induced.

Question 64

The gene encoding apolipoprotein B exists in two isoforms,APOB100 and APOB48.These two forms are produced as a result of

A)tissue-specific expression.
B)a gene mutation that results in a stop codon.
C)RNA editing.
D)alternative splicing.

Question 65

The enzyme dicer chops dsRNA molecules into small pieces of

A)mRNA and miRNA.
B)miRNA and siRNA.
C)siRNA and rRNA.
D)mRNA and siRNA.