Quiz 13: Regulation of Gene Expression

What is the main function of drones in a beehive? A) to mate with queens B) to mate with workers C) to bring food D) to take care of young

What is the essential difference in development of bees of different gender? A) females develop from unfertilized diploid eggs B) males develop from unfertilized diploid eggs C) females develop from unfertilized haploid eggs D) males develop from unfertilized haploid eggs

Why do prokaryotic organisms tend to undergo rapid and reversible alterations in their genes? A) They are not as advanced. B) They are small. C) They are simple. D) They grow quickly.

Which of the following best describes the general strategy of metabolic gene regulation in prokaryotes? A) Genes are always on for early steps in the pathway, but genes for later steps are generally off. B) Genes are turned on and off as conditions change. C) Genes are independently regulated. D) Genes are always on so the bacteria can respond rapidly to changing conditions.

Which of the following is a key difference between eukaryotic and prokaryotic genomes? A) Physical separation of transcription and translation occurs in eukaryotes, but no separation occurs in prokaryotes. B) Genes are arranged in order in eukaryotes, but the order is random in prokaryotes. C) Near simultaneous transcription and translation occurs in eukaryotes, but they are strictly sequential in prokaryotes. D) Gene expression is highly regulated in eukaryotes, but there is a lack of control of gene expression in prokaryotes.

Which of the following components of an operon is a molecule of DNA? A) repressor B) lactose C) mRNA D) operator

Which of the following proteins binds to the operator in the operon model? A) DNA polymerase B) RNA polymerase C) a regulatory protein D) lactose

Genes in operons are transcribed in such a way as to share which of the following molecules? A) mRNA B) tRNA C) protein D) ribosome

Which term refers to a cluster of genes transcribed into a single mRNA unit in the operon model? A) alpha genes B) mRNA cluster C) gene group D) transcription unit

Where does RNA polymerase first bind to on the E. coli lac operon? A) to the transcription initiation site B) to the lacI repressor C) to the promoter D) to the operator

Suppose that a strain of E. coli containing a mutant lac operon is discovered. Also suppose that the mutant operon is normal in terms of its regulation, but the lacY gene produces a defective protein. Which metabolic function will be impaired in this bacterium? A) transport of lactose into the cell B) transacetylase C) binding of the repressor to the operator D) conversion of lactose into monosaccharides

Suppose the lacI repressor gene is permanently silenced by a mutation. What would be the impact on the function of the lac operon? A) There would be no real impact on lac operon expression. B) The lac operon would be transcribed, but at a high level. C) The lac operon would be expressed only when lactose was present. D) The lac operon would be transcribed, but at a low level.

What does the presence of lactose allow in the E. coli lac operon? A) dissociation of the Lac repressor from the promoter B) dissociation of the Lac repressor from the operator C) binding of the Lac repressor to the operator D) binding of the Lac repressor to glucose

Suppose that an E. coli has a mutation in its lac operon such that the Lac repressor could NOT bind the operator, even in the absence of lactose. What would be the result in terms of the function of the operon? A) The lac operon would be transcribed, but at a high level. B) The lac operon would be expressed only when lactose was present. C) There would be no real impact on lac operon expression. D) The lac operon would be transcribed, but at a low level.

Suppose that you observe a mutant E. coli in which CAP is always inactive. In the presence of lactose and low levels of glucose, what would you expect the gene expression from this mutant's lac operon to be? A) inactive B) normal C) greatly reduced D) overactive

Which of the following best explains why E. coli shuts down the trp operon if tryptophan is available in the environment? A) It does not shut down the trp operon, it only lowers the level of trp operon activity. B) The trp operon encodes genes that export tryptophan from the cell; if tryptophan already occurs in the environment, further export is not necessary. C) Synthesizing an amino acid takes energy, so it is a waste of energy to make something that is already available. D) Environmental tryptophan is of higher quality than what the E. coli can make itself.

What is the default state of a repressible operon such as the trp operon? A) normal transcription B) no transcription C) low level transcription D) high level transcription

In catabolite repression, what is indicated by high levels of cAMP? A) low lactose B) low glucose C) high lactose D) high glucose

Where is the Trp repressor gene located? A) just upstream of the trp operon B) on a region of the chromosome quite distant from the trp operon C) just downstream of the trp operon D) adjacent to the Lac repressor gene

What is the single most important stage when regulating eukaryotic gene expression? A) RNA interference B) translational regulation C) degradation of mRNA D) initiation of transcription

Which element(s) does RNA polymerase II bind to? A) transcription factors bound to the promoter B) free-floating transcription factors C) TATA box D) promoter sequence

Which of the following is the correct order in the regulation of gene expression in eukaryotes? A) transcriptional regulation B) translational regulation C) posttranscriptional regulation D) posttranscriptional regulation

Which of the following determines which genes are transcribed? A) posttranscriptional regulation B) transcriptional regulation C) translational regulation D) posttranslational regulation

Which of the following determines the types of mRNA that are available to ribosomes? A) translational regulation B) posttranslational regulation C) transcriptional regulation D) posttranscriptional regulation

Which of the following determines the rate at which proteins are made? A) translational regulation B) transcriptional regulation C) posttranslational regulation D) posttranscriptional regulation

Which of the following determines the availability of finished proteins? A) translational regulation B) transcriptional regulation C) posttranscriptional regulation D) posttranslational regulation

Where does the first general transcription factor bind to? A) site where transcription starts B) TATA box C) activator D) enhancer

Which of the following are the regulatory proteins that play a role in a positive regulatory system that controls the expression of one or more genes? A) introns B) exons C) activators D) enhancers

Which of the following is the function of a coactivator? A) It unwinds the promoter DNA, allowing transcription to begin. B) It recognizes and binds to the TATA box of a protein-coding gene's promoter. C) It binds to the promoter proximal elements to stimulate transcription initiation. D) It forms a bridge between the activators at the enhancer and the proteins at the promoter.

To which portion of the DNA does a steroid hormone receptor bind? A) a response element B) an enhancer C) a gene promoter D) an operator

Why can steroid hormones trigger gene expression in a select number of different cells? A) because only target cells allow the steroid hormone to cross the plasma membrane B) because only the target cells have the correct coactivator C) because only the target cells have a steroid hormone response element encoded in their DNA D) because only the target cells have a nucleus

Which of the following is a key regulatory event for regulating transcription initiation? A) controlling the transition between the inactive and active states of chromatin in the region of H2B histone B) controlling the transition between the inactive and active states of chromatin in the region of introns C) controlling the transition between the inactive and active states of chromatin in the region of a promoter D) controlling the transition between the inactive and active states of chromatin in the region of exons

What is the name of the process that displaces the acetylated nucleosomes in the promoter region from the DNA, or moves them along the DNA away from the promoter? A) translation B) promoter remodelling C) transcriptional regulation D) chromatin remodelling

How does methylation regulate transcription? A) via the addition of a methyl group to cysteine bases of DNA B) via the addition of a methyl group to cysteine residues on RNA polymerase II C) via the addition of a methyl group to cytosine residues on RNA polymerase II D) via the addition of a methyl group to cytosine bases of DNA

Suppose that you are asked to locate some mRNA masking proteins, and are given two rabbits-one male and one female-to use as your cell sources. Also suppose that you decide to do some needle biopsies of one particular tissue, and to extract the masking proteins. Which tissues or organ samples should you collect for analysis? A) skin cells B) testes C) liver cells D) ovaries

What is one function of the 5? UTR (untranslated region) of mRNA? A) to decrease the half-life of mRNA B) to extend the half-life of mRNA C) to stabilize the mRNA structure D) to control the half-life of mRNA

Which type of RNA is transcribed in the nucleus, folded, cleaved by Dicer protein, and is then bound to a target molecule of mRNA? A) an mRNA that never received its poly(A) tail B) miRNA C) an mRNA that was not properly capped D) siRNA

How are the vast majority of proteins expressed early in an animal's development? A) They are translated from preexisting mRNAs present in the unfertilized egg. B) They are translated from preexisting mRNAs delivered by the sperm that fertilized an egg. C) They are transcribed and translated from the unfertilized egg's DNA post-fertilization. D) They are translated from mRNAs that were transcribed from the zygote's DNA in the first three rounds of cell division.

What form must an mRNA assume in order to be targeted by miRNAs for degradation? A) a double-stranded form B) a nuclear form C) a single-stranded form D) a stem-loop form

Which type of RNA is produced from genes that come from outside the cell? A) mRNA B) miRNA C) tRNA D) siRNA

Which of the following is part of posttranslational modification? A) the chemical modification of proteins B) cleavage of poly(A) tails from mRNA C) chromatin remodelling D) the binding of miRNAs to mRNA

Pepsin, a digestive enzyme that degrades proteins in the stomach, is synthesized as pepsinogen and converted to active pepsin in the stomach by the removal of several amino acids. What is the activation of pepsin an example of? A) posttranslational regulation B) transcriptional regulation C) translational regulation D) posttranscriptional regulation

What happens to a protein when it is tagged with ubiquitin? A) The protein is sent to the nucleus. B) The ubiquitin enzyme degrades the protein. C) The protein is sent to the proteasome and is hydrolyzed to amino acids. D) The ubiquitin unfolds the protein.

Which statement refers to genomic imprinting? A) An allele of a given gene is spliced during gametogenesis. B) An allele of a given gene is enhanced during gametogenesis. C) An allele of a given gene is activated during gametogenesis. D) An allele of a given gene is silenced during gametogenesis.

Which of the following is a characteristic of normal cells relative to cancer cells? A) dedifferentiation B) differentiation C) uncontrolled growth D) lack of tumour suppressor proteins

Which of the following genes encode proteins that generally stimulate cell division in normal cells? A) proto-suppressor genes B) proto-oncogenes C) oncogenes D) tumour suppressor genes

Which types of proteins do proto-oncogenes tend to be? A) protein phosphorylases B) membrane-associated proteins C) extracellular receptors and protein kinases D) intracellular receptors

What is the role of a tumour suppressor protein in a cell? A) to promote cell division of abnormal cells B) to slow or halt cell division in abnormal cells C) to trigger DNA replication in preparation for cell division D) to promote cell division of healthy cells

An operator and transcription unit are called an operon.

Many eukaryotic operons are subject to numerous regulatory mechanisms.

Eukaryotic genes are organized into operons.

Eukaryotic genes consist of protein-coding sequences and adjacent regulatory sequences.

Each steroid hormone can bind to its own steroid hormone response unit (SHRU) but NOT to the SHRU associated with other steroid hormones.

Acetylation is irreversible.

When DNA is imprinted, the methylation pattern is preserved.

RNAi is a key regulator of transcription.

Any gene could, theoretically, be specifically silenced by RNAi.

The DNA that encodes siRNA is NOT normally found in the nucleus.

A direct correlation exists between the level of translation and the length of a poly(A) tail.

A benign tumour is usually NOT life-threatening.

Match each term with its definition. a.regulatory protein that activates the expression of an operon's genes b.interfering RNA molecules originally encoded by nuclear DNA c.process of controlling the expression of genes that takes place at the DNA level d.regulatory protein that prevents an operon's genes from being expressed e.inhibition of transcription via DNA methylation f.interfering RNA molecules associated with some viral life cycles g.tumour comprising cells that invade and disrupt the surrounding tissues h.increases expression of an operon's genes i.cluster of prokaryotic genes and their associated DNA regulatory sequences j.tumour comprising undifferentiated cells that stay together in a single mass k. spread of malignant cells through the blood or lymphatic system l. removes a nucleosome from DNA to expose a promoter -operon

Match each term with its definition. a.regulatory protein that activates the expression of an operon's genes b.interfering RNA molecules originally encoded by nuclear DNA c.process of controlling the expression of genes that takes place at the DNA level d.regulatory protein that prevents an operon's genes from being expressed e.inhibition of transcription via DNA methylation f.interfering RNA molecules associated with some viral life cycles g.tumour comprising cells that invade and disrupt the surrounding tissues h.increases expression of an operon's genes i.cluster of prokaryotic genes and their associated DNA regulatory sequences j.tumour comprising undifferentiated cells that stay together in a single mass k. spread of malignant cells through the blood or lymphatic system l. removes a nucleosome from DNA to expose a promoter -transcriptional regulation

Match each term with its definition. a.regulatory protein that activates the expression of an operon's genes b.interfering RNA molecules originally encoded by nuclear DNA c.process of controlling the expression of genes that takes place at the DNA level d.regulatory protein that prevents an operon's genes from being expressed e.inhibition of transcription via DNA methylation f.interfering RNA molecules associated with some viral life cycles g.tumour comprising cells that invade and disrupt the surrounding tissues h.increases expression of an operon's genes i.cluster of prokaryotic genes and their associated DNA regulatory sequences j.tumour comprising undifferentiated cells that stay together in a single mass k. spread of malignant cells through the blood or lymphatic system l. removes a nucleosome from DNA to expose a promoter -inducer

Match each term with its definition. a.regulatory protein that activates the expression of an operon's genes b.interfering RNA molecules originally encoded by nuclear DNA c.process of controlling the expression of genes that takes place at the DNA level d.regulatory protein that prevents an operon's genes from being expressed e.inhibition of transcription via DNA methylation f.interfering RNA molecules associated with some viral life cycles g.tumour comprising cells that invade and disrupt the surrounding tissues h.increases expression of an operon's genes i.cluster of prokaryotic genes and their associated DNA regulatory sequences j.tumour comprising undifferentiated cells that stay together in a single mass k. spread of malignant cells through the blood or lymphatic system l. removes a nucleosome from DNA to expose a promoter -repressor

Match each term with its definition. a.regulatory protein that activates the expression of an operon's genes b.interfering RNA molecules originally encoded by nuclear DNA c.process of controlling the expression of genes that takes place at the DNA level d.regulatory protein that prevents an operon's genes from being expressed e.inhibition of transcription via DNA methylation f.interfering RNA molecules associated with some viral life cycles g.tumour comprising cells that invade and disrupt the surrounding tissues h.increases expression of an operon's genes i.cluster of prokaryotic genes and their associated DNA regulatory sequences j.tumour comprising undifferentiated cells that stay together in a single mass k. spread of malignant cells through the blood or lymphatic system l. removes a nucleosome from DNA to expose a promoter -miRNA

Match each term with its definition. a.regulatory protein that activates the expression of an operon's genes b.interfering RNA molecules originally encoded by nuclear DNA c.process of controlling the expression of genes that takes place at the DNA level d.regulatory protein that prevents an operon's genes from being expressed e.inhibition of transcription via DNA methylation f.interfering RNA molecules associated with some viral life cycles g.tumour comprising cells that invade and disrupt the surrounding tissues h.increases expression of an operon's genes i.cluster of prokaryotic genes and their associated DNA regulatory sequences j.tumour comprising undifferentiated cells that stay together in a single mass k. spread of malignant cells through the blood or lymphatic system l. removes a nucleosome from DNA to expose a promoter -activator

Match each term with its definition. a.regulatory protein that activates the expression of an operon's genes b.interfering RNA molecules originally encoded by nuclear DNA c.process of controlling the expression of genes that takes place at the DNA level d.regulatory protein that prevents an operon's genes from being expressed e.inhibition of transcription via DNA methylation f.interfering RNA molecules associated with some viral life cycles g.tumour comprising cells that invade and disrupt the surrounding tissues h.increases expression of an operon's genes i.cluster of prokaryotic genes and their associated DNA regulatory sequences j.tumour comprising undifferentiated cells that stay together in a single mass k. spread of malignant cells through the blood or lymphatic system l. removes a nucleosome from DNA to expose a promoter -silencing

Match each term with its definition. a.regulatory protein that activates the expression of an operon's genes b.interfering RNA molecules originally encoded by nuclear DNA c.process of controlling the expression of genes that takes place at the DNA level d.regulatory protein that prevents an operon's genes from being expressed e.inhibition of transcription via DNA methylation f.interfering RNA molecules associated with some viral life cycles g.tumour comprising cells that invade and disrupt the surrounding tissues h.increases expression of an operon's genes i.cluster of prokaryotic genes and their associated DNA regulatory sequences j.tumour comprising undifferentiated cells that stay together in a single mass k. spread of malignant cells through the blood or lymphatic system l. removes a nucleosome from DNA to expose a promoter -benign

Match each term with its definition. a.regulatory protein that activates the expression of an operon's genes b.interfering RNA molecules originally encoded by nuclear DNA c.process of controlling the expression of genes that takes place at the DNA level d.regulatory protein that prevents an operon's genes from being expressed e.inhibition of transcription via DNA methylation f.interfering RNA molecules associated with some viral life cycles g.tumour comprising cells that invade and disrupt the surrounding tissues h.increases expression of an operon's genes i.cluster of prokaryotic genes and their associated DNA regulatory sequences j.tumour comprising undifferentiated cells that stay together in a single mass k. spread of malignant cells through the blood or lymphatic system l. removes a nucleosome from DNA to expose a promoter -metastasis

Match each term with its definition. a.regulatory protein that activates the expression of an operon's genes b.interfering RNA molecules originally encoded by nuclear DNA c.process of controlling the expression of genes that takes place at the DNA level d.regulatory protein that prevents an operon's genes from being expressed e.inhibition of transcription via DNA methylation f.interfering RNA molecules associated with some viral life cycles g.tumour comprising cells that invade and disrupt the surrounding tissues h.increases expression of an operon's genes i.cluster of prokaryotic genes and their associated DNA regulatory sequences j.tumour comprising undifferentiated cells that stay together in a single mass k. spread of malignant cells through the blood or lymphatic system l. removes a nucleosome from DNA to expose a promoter -siRNA

Match each term with its definition. a.regulatory protein that activates the expression of an operon's genes b.interfering RNA molecules originally encoded by nuclear DNA c.process of controlling the expression of genes that takes place at the DNA level d.regulatory protein that prevents an operon's genes from being expressed e.inhibition of transcription via DNA methylation f.interfering RNA molecules associated with some viral life cycles g.tumour comprising cells that invade and disrupt the surrounding tissues h.increases expression of an operon's genes i.cluster of prokaryotic genes and their associated DNA regulatory sequences j.tumour comprising undifferentiated cells that stay together in a single mass k. spread of malignant cells through the blood or lymphatic system l. removes a nucleosome from DNA to expose a promoter -chromatin remodelling

Match each term with its definition. a.regulatory protein that activates the expression of an operon's genes b.interfering RNA molecules originally encoded by nuclear DNA c.process of controlling the expression of genes that takes place at the DNA level d.regulatory protein that prevents an operon's genes from being expressed e.inhibition of transcription via DNA methylation f.interfering RNA molecules associated with some viral life cycles g.tumour comprising cells that invade and disrupt the surrounding tissues h.increases expression of an operon's genes i.cluster of prokaryotic genes and their associated DNA regulatory sequences j.tumour comprising undifferentiated cells that stay together in a single mass k. spread of malignant cells through the blood or lymphatic system l. removes a nucleosome from DNA to expose a promoter -malignant

Identify each labelled part of this illustration of eukaryotic DNA. -enhancer

Identify each labelled part of this illustration of eukaryotic DNA. -RNA polymerase

Identify each labelled part of this illustration of eukaryotic DNA. -activators

Identify each labelled part of this illustration of eukaryotic DNA. -coactivator multiprotein complex

Identify each labelled part of this illustration of eukaryotic DNA. -proximal promoter region

Identify each labelled part of this illustration of eukaryotic DNA. -transcription initiation site

Identify each labelled part of this illustration of eukaryotic DNA. -promoter

Identify each labelled part on the illustration of the Lac operon. -transcription termination site

Identify each labelled part on the illustration of the Lac operon. -lacI

Identify each labelled part on the illustration of the Lac operon. -Lac repressor

Identify each labelled part on the illustration of the Lac operon. -regulatory gene

Identify each labelled part on the illustration of the Lac operon. -lacA

Identify each labelled part on the illustration of the Lac operon. -promoter

Identify each labelled part on the illustration of the Lac operon. -RNA polymerase

Identify each labelled part on the illustration of the Lac operon. -operator

Identify each labelled part on the illustration of the Lac operon. -lac operon

Identify each labelled part on the illustration of the Lac operon. -lacY

Identify each labelled part on the illustration of the Lac operon. -transcription initiation site

Identify each labelled part on the illustration of the Lac operon. -lacZ