genetics ch.17

What is the size of the nucleosome-free region found at the core promoter of active genes? 15 bp 1,500 bp 15,000 bp 150 bp

150 bp

You are studying a bidirectional enhancer with the sequence 5'-CCTA-3'. Regulatory transcription factors that bind this sequence should also bind ______. 5'-GGAT-3' (Bidirectional enhancers function in the forward or reverse direction. Notice 3'-ATCC-5' is the reverse of 5'-CCTA-3'.) 3'-ATCC-5' 3'-TAGG-5' (Bidirectional enhancers function in the forward or reverse direction. Notice 3'-ATCC-5' is the reverse of 5'-CCTA-3'.)

3'-ATCC-5'

Eviction or destabilization of histone octamers, allowing RNA pol II to pass, and elongation to occur. Recruitment of general transcription factors and RNA Pol II to the core promoter, allowing the formation of a preinitiation complex. Binding of an activator to an enhancer in the NFR. Recruitment of a chromatin-remodeling complex and a histone-modifying enzyme

Binding of an activator to an enhancer in the NFR. Recruitment of a chromatin-remodeling complex and a histone-modifying enzyme Recruitment of general transcription factors and RNA Pol II to the core promoter, allowing the formation of a preinitiation complex. Eviction or destabilization of histone octamers, allowing RNA pol II to pass, and elongation to occur.

Select all statements that are examples of how environmental factors may function as epigenetic regulators. Genomic imprinting during development leads to phenotypic changes. Body differences between queen bees and worker bees are caused by dietary differences. Flowering and/or seed germination occurs when certain flowering plants are exposed to colder temperatures during the previous winter. Exposure to tobacco smoke has been shown to alter DNA methylation and covalent modifications of specific genes in lung cells. Phenotypic changes occur due to a spontaneous frameshift mutation that alters protein folding.

Body differences between queen bees and worker bees are caused by dietary differences. Flowering and/or seed germination occurs when certain flowering plants are exposed to colder temperatures during the previous winter. Exposure to tobacco smoke has been shown to alter DNA methylation and covalent modifications of specific genes in lung cells.

As a result of a diet of royal jelly, queen bees develop differences in _____ when compared with worker bees. histone acetylation nucleosome placement histone phosphorylation histone methylation DNA methylation

DNA methylation

Select all of these that are true regarding epigenetics. Epigenetic changes are transmissible from cell to cell. Variations of gene expression result from mutations. Epigenetic changes may be transmitted to offspring. Variations of gene expression are unrelated to variations in the DNA base sequence. Variations are reversible from one generation to the next.

Epigenetic changes are transmissible from cell to cell. Epigenetic changes may be transmitted to offspring. Variations of gene expression are unrelated to variations in the DNA base sequence. Variations are reversible from one generation to the next.

True or false: Most regulatory transcription factors bind directly to RNA polymerase. True (Most regulatory transcription factors do not bind directly to RNA polymerase, but rather exert their effects through TFIID, mediator, or nucleosome structure.) False

False

True or false: Regulatory elements must be located within 200 base pairs upstream from the core promoter. True (Regulatory elements are often located within 200 bp upstream from the core promoter, but can also be quite distant, even 100,000 bp away.) False

False

Excess iron in animal cells is stored within a hollow, spherical protein known as ____

Ferritin

Nucleosomes containing the histone variant _____, which are usually found at the +1 nucleosome, are thought to be more easily removed from the DNA than those containing the standard histone _____.

H2AZ and H2A

Select the histones for which variants have been identified. H2B H2A H4 H1 H3

H2B H2A H1 H3

For high iron levels in a eukaryotic cell, IRP binds to IRE and inhibits translation of the transferrin receptor mRNA. (The IRE is located in the 3' UTR, so binding of IRP does not inhibit translation.) IRP binds to IRE and activates translation of the transferrin receptor mRNA. IRP cannot bind to IRE and so the transferrin receptor mRNA gets degraded. IRP cannot bind to IRE and so the transferrin receptor mRNA is more stable. (IRP binding to IRE enhances mRNA stability.)

IRP cannot bind to IRE and so the transferrin receptor mRNA gets degraded.

How does iron regulatory protein exert its effect on ferritin mRNA? Iron regulatory protein (IRP) binds to the iron response element (IRE) in the 5' UTR, and thus inhibits ferritin translation. Iron regulatory protein (IRP) binds to the iron response element (IRE) in the coding region of the gene, and thus inhibits ferritin translation. Iron regulatory protein (IRP) binds to the iron response element (IRE) in the 3' UTR, and thus inhibits ferritin translation. (The IRE is located in the 5' UTR of the ferritin mRNA.)

Iron regulatory protein (IRP) binds to the iron response element (IRE) in the 5' UTR, and thus inhibits ferritin translation.

Select all of these that are examples of epigenetics. Localization of histone variants DNA methylation Chromatin remodeling DNA translocation DNA mutation (Epigenetics is the variation of gene expression that is not related to the variation of the DNA.) Covalent histone modification

Localization of histone variants DNA methylation Chromatin remodeling Covalent histone modification

Select the most common process regarding methylation. De novo methylation Maintenance methylation Demethylation (De novo methylation and demethylation occur infrequently and are highly regulated events.)

Maintenance methylation

TFIID binds to the _____ box and helps recruit RNA polymerase II to the core____

TATA and promoter

Activator proteins might help ___ bind to the ___ box.

TFIID and TATA

Select all of these that are environmental factors that promote epigenetic changes. Temperature X chromosome inactivation (This is an example of an epigenetic change rather than an environmental factor promoting the change.) Toxins Diet Genomic imprinting (This is an example of an epigenetic change rather than an environmental factor promoting the change.)

Temperature Toxins Diet

Select the ways methylation can affect transcription. RNA polymerase movement is hindered by CpG methylation. The methylation of CpG islands may prevent or enhance the binding of regulatory transcription factors to the promoter region. Methyl-CpG binding proteins recruit other proteins that enhance transcription. Methyl-CpG binding proteins recruit other proteins that inhibit transcription.

The methylation of CpG islands may prevent or enhance the binding of regulatory transcription factors to the promoter region. Methyl-CpG binding proteins recruit other proteins that inhibit transcription.

True or false: The iron-regulatory protein (IRP) binds to a regulatory sequence in mRNA called the iron response element (IRE). True False (The IRP exerts its effects by binding to the iron response element, which is found in the mRNAs the encode both ferritin and the transferrin receptor.)

True

True or false: The methylation state of DNA is inherited during cell division. True False(DNA methylation patterns are retained following DNA replication and into future daughter cells.)

True

Which of the following statements regarding regulation of the transferrin receptor mRNA is correct? When iron is abundant, the iron regulatory protein binds to and stabilizes the transferrin receptor mRNA. (The transferrin receptor mRNA is degraded when the iron concentration is high.) When iron is scarce, the iron regulatory protein binds to and stabilizes the transferrin receptor mRNA. The iron response element is located in the 5' UTR of the transferrin receptor mRNA. The iron response element is located in the coding region of the transferrin receptor mRNA. (The IRE is found in the 3' UTR of the transferrin receptor mRNA.)

When iron is scarce, the iron regulatory protein binds to and stabilizes the transferrin receptor mRNA.

A regulatory element that functions in the forward or reverse direction is said to be ____

bidirectional

For Arabidopsis, flowering in spring due to exposure of colder temperatures in the winter is associated with ____ modification of ____ that occurs in the winter and persists into the spring

covalent and histones

Which types of epigenetic changes have been detected in human lung cells as a result of exposure to tobacco smoke? localization of histone variants covalent histone modifications changes in DNA methylation alternative splicing patterns chromatin remodeling

covalent histone modifications changes in DNA methylation

The cress plant Arabidopsis undergoes vernalization, where flowering in spring requires exposure to colder temperatures during the preceding winter. Which type of modification persisting from winter into spring has been associated with vernalization? covalent modification of histones associated with specific genes methylation of DNA for flowering genes transcription factors that up regulate mRNA production specific activator proteins that enhance transcription of flowering genes

covalent modification of histones associated with specific genes

The methylation of DNA that was previously unmethylated is called _____ ____ methylation.

de novo

The methylation of a previously unmethylated site is called de novo mutation. de novo methylation. induced mutation. maintenance methylation. (The methylation of hemimethylated sites is called maintenance methylation.)

de novo methylation.

Activators bind to RNA. repressors. enhancers. silencers.

enhancers.

DNA methylation, chromatin remodeling, covalent histone modification and localization of histone variants are all examples of ___

epigenetics

Variation of gene expression that is transmissible and reversible but not related to the variation in the DNA is called _____

epigenetics

Variation of gene expression that is transmissible and reversible but not related to the variation in the DNA is called _____.

epigenetics

*Figure 17.21 The regulation of iron assimilation genes by IRP and IRE* This figure depicts the regulation of ______ mRNA under _______ cytosolic levels of iron. ferritin; low transferrin receptor; low (The IRE is in the 3' UTR for the transferrin receptor gene.) ferritin; high transferrin receptor; high

ferritin; high

Core _____ proteins contain a globular domain and a flexible amino-terminal tail. DNA wraps around the globular domains, and the amino-terminal tails protrude from the chromatin.

histones

When iron levels are abundant in the cytosol, iron binds the IRP, enabling the translation of transferrin. (When iron levels are abundant within the cytosol, the iron binds to IRP, which causes IRP to dissociate from transferrin receptor mRNA.) iron binds the IRE, inhibiting the translation of ferritin. (Iron binds to IRP, preventing IRP and IRE binding.) iron binds the IRP, enabling the translation of ferritin. iron binds the IRE, inhibiting the translation of transferrin.

iron binds the IRP, enabling the translation of ferritin.

The two mRNAs that encode ferritin and the transferrin receptor are both influenced by an RNA-binding protein known as the ____-___ protein.

iron regulatory

The region of the ferritin and the transferrin receptor mRNAs that the iron-regulatory protein (IRP) binds to is called the ____ ____ ___

iron response element

Iron assimilation in mammalian cells is regulated by iron-regulatory proteins which can bind to mRNA. histone modification of the ferritin and transferrin genes. transient methylation of the ferritin and transferrin genes. RNA silencing of genes involved in iron transport.

iron-regulatory proteins which can bind to mRNA.

A process called ____ methylation seems to be the primary mechanism by which DNA in vertebrate and plant cells are methylated.

maintenance

The methylation of hemimethylated sites is called an induced mutation. de novo methylation. (The methylation of a previously unmethylated site is called de novo methylation.) maintenance methylation. a de novo mutation.

maintenance methylation.

Proteins called ____-CpG-_____proteins bind methylated sequences and recruit other proteins to the region to ____transcription.

methyl binding and inhibit

If fully methylated DNA is introduced into a plant or animal cell, in subsequent generations the DNA will be ______ . If the same sequence of nonmethylated DNA is introduced into a cell, it will be ____ in daughter cells.

methylated and nonmethylated

For humans, exposure to tobacco smoke has been associated with changes in DNA ____ and covalent ____ modifications of specific genes in lung cells.

methylation and histone

DNA translocases are. proteins that are involved in moving methyl groups between CpG islands. proteins that enhance the ability of RNA polymerase to interact with mediator. motor proteins that are found in chromatin-remodeling complexes. motor proteins that mediate the action of steroid hormones.

motor proteins that are found in chromatin-remodeling complexes.

Plants and animals require a greater level of gene regulation than single-celled eukaryotes because of multicellularity. developmental stages. different tissue types. more complex cell structure. organelles.

multicellularity. developmental stages. different tissue types. more complex cell structure.

The core promoter of active genes is found in a(n) ____-free ____ , which is a segment of DNA that is missing histones.

nucleosome and region

The placement of ____ at or near promoters often plays a key role in whether a gene is active or inactive.

nucleosomes

ATP-dependent chromatin remodeling is carried out by a protein complex that recognizes _____and uses _____ to alter their configuration.

nucleosomes and ATP

Repressors inhibit TFIID by preventing the binding of TFIID to the TATA box. inhibiting the ability of TFIID to recruit RNA polymerase II to the core promoter. changing nucleosome structure. inhibiting the function of mediator.

preventing the binding of TFIID to the TATA box. inhibiting the ability of TFIID to recruit RNA polymerase II to the core promoter.

The pattern of covalent modifications to histone tails provides binding sites for proteins that affect the degree of transcription. Certain patterns can either ___or ____transcription.

promote and inhibit

Transcription factors that affect the ability of RNA polymerase to begin the transcription process may work by regulating the binding of the transcriptional complex to the core promoter. preventing DNA replication. regulating RNA processing. controlling the switch from the initiation to the elongation stage of transcription.

regulating the binding of the transcriptional complex to the core promoter. controlling the switch from the initiation to the elongation stage of transcription.

The ability of humans to develop tans to protect their skin cells from UV rays by inducing genes that provide protection against UV radiation is an example of gene ___

regulation

DNA sequences in eukaryotes that can be bound by regulatory transcription factors, which then affect the ability of RNA polymerase to transcribe a particular gene are called ______. regulatory sequences core promoters regulatory elements operator sequences (Operator sequences are found in prokaryotic cells.) control elements

regulatory sequences regulatory elements control elements

Regulatory transcription factors that prevent transcription from occurring are called ____

repressors

Queen bees differ from worker bees because they have been fed _____ jelly throughout their lifespan and show differences in DNA ___ that affect expression of many of their genes.

royal and methylation

Repressors bind to silencers. enhancers. activators.

silencers.

De novo methylation refers to the methylation of any DNA, regardless of previous methylation status. the methylation of DNA that was previously methylated. the methylation of DNA that was previously unmethylated.

the methylation of DNA that was previously unmethylated.

A ___ ____is a protein that influences the ability of RNA polymerase to transcribe a given gene.

transcription factor

*Figure 17.21 The regulation of iron assimilation genes by IRP and IRE* This figure depicts the regulation of ______ mRNA under _______ cytosolic levels of iron. ferritin; high (The IRE is in the 5' UTR for the ferritin gene.) transferrin receptor; low ferritin; low transferrin receptor; high

transferrin receptor; high

In animals, the major protein that carries iron in the bloodstream is ferritin. (Ferritin is an intracellular protein that stores iron.) calmodulin. hemoglobin. (Hemoglobin is an iron-containing protein that carries oxygen in the bloodstream.) transferrin.

transferrin.

When a fully methylated DNA segment of DNA is replicated, the newly made daughter strand contains ____ cytosines. This DNA is said to be _____.

unmethylated and hemimethylated

Select the common types of covalent modifications made to the amino-terminal tails of histones. Acetylation Phosphorylation Ubiquitination Methylation

Acetylation Phosphorylation Methylation

Place the steps in glucocorticoid hormone and receptor action in order from first to last. Instructions HSP90 is released from the glucocorticoid receptor. The glucocorticoid hormone binds to glucocorticoid receptors. Two glucocorticoid receptors form a homodimer and travel through a nuclear pore into the nucleus. The glucocorticoid hormone diffuses through the plasma membrane.

The glucocorticoid hormone diffuses through the plasma membrane. The glucocorticoid hormone binds to glucocorticoid receptors. HSP90 is released from the glucocorticoid receptor. Two glucocorticoid receptors form a homodimer and travel through a nuclear pore into the nucleus.

Lysine residues on core histone proteins can be acetylated by enzymes called histone____

acetyltransferase

Steroid hormones are synthesized by ___ glands and secreted into the bloodstream, ultimately affecting the transcription or expression of genes in target cells.

endocrine

A glucocorticoid response element functions as a(n) terminator. silencer. repressor. enhancer.

enhancer

The binding of a regulatory transcription factor to a(n) _____ can stimulate transcription 10- to 1000-fold, which is called ______ regulation.

enhancer and up

Methylation of the cytosine in both strands is called ____ methylation, and methylation of only one strand is called _____.

full and hemimethylation

Gene regulation means that gene expression can be controlled so that genes can be expressed at high or low levels. gene expression is controlled so that all genes in a genome are expressed at the same level. only certain genes are included in the genome of a species.

gene expression can be controlled so that genes can be expressed at high or low levels.

Most eukaryotic genes are regulated by one factor. many factors. zero factors.

many factors.

At the end of many eukaryotic genes, a well-positioned nucleosome is followed by an NFR. This arrangement may be important for transcriptional repression. transcriptional termination. transcriptional initiation.

transcriptional termination.

All chromatin-remodeling complexes have motor proteins called DNA ____ that move along the DNA.

translocases

In general ____CpG islands correlate with active genes, and _____ CpG islands correlate with suppressed genes.

unmethylated and methylated

An enhancer is a DNA element that is bound by a regulatory transcription factor, which leads to transcriptional repression. DNA replication. down regulation. up regulation.

up regulation.

5-methylcytosine is formed by. cytosine methyltransferase. DNA methyltransferase. RNA methyltransferase.

DNA methyltransferase.

The binding of a glucocorticoid receptor homodimer to a glucocorticoid response element ____ the transcription of the nearby gene.

activates

Genes that are highly regulated and may be expressed only in certain cell types are called ___- ____genes.

tissue specific

What kind of protein is expected to enhance the ability of TFIID to initiate transcription? Repressor proteins Activator proteins Mediator

Activator proteins

What effect can ATP-dependent chromatin remodeling have on transcription? Both activation and repression. Activation only. Repression only.

Both activation and repression.

Select ways in which histone modifications affect the level of transcription. By influencing interactions between DNA and histones within nucleosomes By changing the histone modification patterns that are recognized by other proteins By stopping all transcription in the cell By moving histones out of the nucleus

By influencing interactions between DNA and histones within nucleosomes By changing the histone modification patterns that are recognized by other proteins

Stretches of DNA of 1000-2000 bp in length containing a high number of CpG sites and found near gene promoters are called stop codons. start codons. transcription factors. CpG islands.

CpG islands.

What enzymes can add acetyl groups onto the lysines of core histone proteins? Histone acetyltransferases Histone acetylases Histone deacetylases Histone lysinases

Histone acetyltransferases

True or false: The function of regulatory transcription factors is modulated. True False (Regulatory transcription factor function is modulated to ensure genes are turned on at the right time, in the correct cell type, and under appropriate environmental conditions.)

True

A regulatory transcription factor that enhances the rate of transcription is called a(n) ____

activator

Steroid hormones bind regulatory transcription factors called steroid receptors in order to affect gene transcription. be secreted into the bloodstream. (Before a hormone can be secreted it must be transcribed and translated.) make a covalent modification.

affect gene transcription.

Relative to the promoter for a gene of interest, regulatory elements are located within 200 bp. (There is striking variation in the location of regulatory elements. They are often about 200 bp upstream from the promoter, but may be as far as 100,000 bp away.) at various distances. on top of the promoter. more than 100,000 bp away. (There is striking variation in the location of regulatory elements. They are often about 200 bp upstream from the promoter, but may be as far as 100,000 bp away.)

at various distances.

During transcription elongation, histones are evicted and transferred to histone ___ , which are proteins that bind to evicted histones and aid in the assembly of histones.

chaperones

The SWI/SNF-family, the ISWI-family, the INO80-family, and the Mi-2 family are families of chromatin-remodeling complexes. general transcription factors. RNA polymerases. regulatory transcription factors.

chromatin-remodeling complexes.

Activator proteins often increase transcription through an interaction with RNA polymerase. repressors. RNA. coactivators.

coactivators.

Regulatory elements that inhibit transcription are called silencers and their effect on transcription is called ______ regulation.. up down

down

You are studying a transcription factor that binds to DNA near a gene of interest. You discover that once the transcription factor binds, transcription of your gene of interest becomes undetectable. This is an example of up regulation. down regulation. a mediator. an activator.

down regulation.

The function of regulatory transcription factors must be modulated to ensure that genes are turned on in the correct cell type. at the proper time. under the appropriate environmental conditions. all the time. in growing cells only.

in the correct cell type. at the proper time. under the appropriate environmental conditions.

The attachment of an acetyl group to a core histone protein eliminates the positive charge on the side chain of the amino acid ___, thus disrupting the electrostatic attraction between the histone and the negatively charged DNA backbone.

lysine

When fully methylated DNA is replicated, it is initially hemimethylated. The hemimethylated DNA is recognized by DNA methyltransferase, which makes it fully methylated. This process is called maintenance methylation. replication methylation. de novo methylation.

maintenance methylation.

The function of TFIID is inhibited by ____-, which prevent the binding of TFIID to the _____ box.

repressors and TATA

What affect does acetylation have on lysines in core histone protein tails? Makes an additional negative charge on lysine, causing the DNA and the histone to repel one another Eliminates the negative charge on lysine, disrupting the electrostatic attraction between the histone and the positively charged DNA backbone Makes an additional positive charge on lysine, causing the DNA to bind more strongly to the histone Eliminates the positive charge on lysine, disrupting the electrostatic attraction between the histone and the negatively charged DNA backbone

Eliminates the positive charge on lysine, disrupting the electrostatic attraction between the histone and the negatively charged DNA backbone

Activator proteins stimulate mediator to make what modification on RNA polymerase II? Phosphorylation Methylation (Methylation is associated with inactivation of gene regions.) Acetylation

Phosphorylation

Select the steps at which gene regulation can occur. Posttranslational modification Transcription Translation RNA processing DNA replication

Posttranslational modification Transcription Translation RNA processing

The phenomenon in which the combination of many factors determines the expression of a given gene is known as _____ ____

combinatorial control

DNA methylation is the ____ attachment of methyl groups to DNA.

covalent

In DNA methylation, the base that is typically methylated is the ______ in ______ sequences. guanine ; CpG guanine ; ApG adenine ; ApG cytosine ; ApC cytosine ; CpG

cytosine ; CpG

ATP-____ ______ remodeling uses the energy of ATP hydrolysis to change the position or composition of nucleosomes.

dependent chromatin

Human nerve cells and muscle cells look quite different from each other due to differences in DNA content. gene regulation. cell cycle.

gene regulation.

According to the ____ ____hypothesis, the pattern of histone ___ acts like a language or code in specifying alterations in chromatin structure.

histone code and modification

Before transcription elongation can occur, ____ have to be evicted, partially displaced or destabilized so that RNA polymerase II can pass.

histones

The protein complex that facilitates the interaction between RNA polymerase II and regulatory transcription factors is called ____ .

mediator

The covalent attachment of a -CH3 group to DNA is known as DNA glycosylation. carboxylation. acetylation. phosphorylation. methylation.

methylation.

*Figure 17.9 Nucleosomes arrangements and composition in the vicinity of a protein-encoding gene. * In this figure, the arrows point to ____ -____ ____ .

nucleosome free region

Histone modifications can affect transcription levels by directly influencing interactions within ____ , and also by altering the _____ code.

nucleosomes and histone

A change in chromatin confirmation from closed to open often involves the movement of helicases. promoters. genes. nucleosomes.

nucleosomes.

Once inside the cell, the glucocorticoid hormone binds to a glucocorticoid _______, releasing it from a protein known as HSP90. enhancer receptor activator response element repressor

receptor

The regulatory transcription factors that respond to glucocorticoid hormones are called glucocorticoid ____

receptors

The phenomenon where gene expression is controlled so that genes can be expressed at high or low levels is called gene ____

regulation

Genes that code for proteins that are required in most cells of a multicellular organism are called ______. housekeeping genes tissue-specific genes CpG islands promoter genes

housekeeping genes

CpG islands near the promoters of tissue-specific genes are often methylated. phosphorylated. hemimethylated. unmethylated. (Expression of tissue-specific genes are highly regulated and may be silenced by methylation of CpG islands.)

methylated.

Mediator controls the ability of RNA polymerase II to begin the termination stage of transcription. RNA polymerase I to progress to the elongation stage of transcription. RNA polymerase II to progress to the elongation stage of transcription. RNA polymerase I to begin the initiation stage of transcription. RNA polymerase II to begin the initiation stage of transcription.

RNA polymerase II to progress to the elongation stage of transcription.

What are the most common ways that regulatory transcription factors influence the ability of RNA polymerase II to transcribe a given gene? Recruit proteins that affect nucleosomes Deletion of the TATA box Bind directly to RNA polymerase II Influence the function of TFIID Influence the function of mediator

Recruit proteins that affect nucleosomes Influence the function of TFIID Influence the function of mediator

In a multicellular organism, housekeeping genes tend to be expressed ______. in most cell types only during embryonic development only in certain cell types in all cell types

in most cell types

Proteins that regulate the rate of transcription of target genes are called _____ transcription factors.

regulatory

DNA sequences that are analogous to the operator sites found near bacterial promoters are called _____ elements or _____ elements.

regulatory and control

Activator proteins stimulate the ability of ____ to phosphorylate the carboxyl-terminus of RNA polymerase II, which facilitates the switch between transcriptional initiation and elongation.

mediator

*Figure 17.11 DNA methylation on cytosine bases* The CG sequence in this figure is said to be ______. heteromethylated unmethylated fully methylated (The cytosine on only one of the two strands is methylated.) quasimethylated hemimethylated

hemimethylated

The function of TFIID is to bind to the TATA box and recruit RNA polymerase II to the core promoter. bind to an enhancer to increase transcription from the core promoter. prevent the binding of RNA polymerase II to the core promoter. bind to the core promoter and recruit RNA polymerase II to the TATA box.

bind to the TATA box and recruit RNA polymerase II to the core promoter.

A protein that increases the rate of transcription but does not directly bind to the DNA is called a ____

coactivator

General transcription factors are required for the binding of ___ ____ to the core promoter and its progression to the elongation stage.

RNA polymerase

Following the binding of a hormone, two glucocorticoid _____ form a dimer and travel to the _____.

receptors and nucleus

Most histone genes encode standard histone proteins, but some have accumulated mutations that change the amino acid sequence of the histone proteins. These proteins are called histone ____

variants

A gene you are studying has an NFR flanked by a -1 and +1 nucleosome. Its transcriptional start site is located at the boundary between the NFR and the +1 nucleosome. This gene is likely found in mice. (In animals, the transcriptional start site is located about 60 bp upstream, into the NFR region.) humans. bacteria. yeast.

yeast.

Select examples of how gene regulation benefits eukaryotic organisms. The ability to respond to environmental stresses The ability to remove deleterious genes The ability to respond to changes in nutrient availability

The ability to respond to environmental stresses The ability to respond to changes in nutrient availability

DNA methyltransferase is an enzyme that attaches a methyl group to the _____ position of the _____ base.

5 and cytosine

What DNA sequence is methylated? 5'-CG-3' 5'-GC-3' 5'-AC-3' 5'-CA-3'

5'-CG-3'

If chromatin is in a closed conformation, nucleosome position and histone composition enhance the ability of transcription factors to gain access to and bind their target sequences in the promoter DNA. make it difficult for the DNA to become single stranded during transcription. make it difficult for transcription factors to gain access to and bind their target sequences in the promoter DNA. make it easier for the DNA to become single stranded during transcription.

make it difficult for transcription factors to gain access to and bind their target sequences in the promoter DNA.

If chromatin is in a ____ conformation, transcription may be difficult or impossible.

closed

If gene regulation acts to prevent translation, what molecule will not be produced? DNA mRNA (mRNA will not be produced if transcription or processing has been prevented.) pre-mRNA Protein

Protein

*Figure 17.9 Nucleosomes arrangements and composition in the vicinity of a protein-encoding gene. * The left arrow in this figure highlights what? The translational start site of a protein-encoding gene (The image shows DNA which would be transcribed rather than translated.) The transcriptional start site of a protein-encoding gene The telomere of a chromosome The origin of replication of a chromosome The centromere of a chromosome

The transcriptional start site of a protein-encoding gene