Chapter 19 Genetics McGraw Hill

Arrange the steps that occur in the production and processing of a miRNA in the correct order, starting at the top.

1. The miRNA gene is transcribed 2. Drosha 3. The pre-miRNA 4. Dicer 5. The miRNA : miRNA 6. One of the strands

The following diagram shows two scenarios for the interaction between 4E-BP1 and eIF4E. Which scenario(s) show(s) a cell that does not have enough nutrients to grow?

A

Which statement accurately describes promoters and enhancers in two different topologically associating domains (TADs)?

A promoter and an enhancer within two separate TADs cannot interact with each other.

Eukaryotic cells produce several types of small RNAs that can prevent expression of specific genes through complementary base pairing. Each small RNA class performs its function by associating with a specific member of the ______ protein family

Argonaute

Which of the following proteins are considered transcription factors?

Basal factors Activators Repressors

What proteins bind to the promoter of a gene?

Basal transcription factors

What DNA-binding domain is found in most leucine zipper proteins?

Basic domain

What fields of study are included in bioinformatics?

Biology, computer science, and information technology

A repressor protein typically has a(n) _____- binding domain, a(n) ______domain that allows it to interact with corepressors, and a(n) _________domain that allows two protein subunits to interact.

DNA Repression Dimerization

Interactions among basal factors, Mediator, and activators bound to distant enhancers are possible because _____.

DNA is flexible and can loop

After transcription, microRNAs (miRNAs) are cleaved by the ribonucleases _____ (in the nucleus) and __________ (in the cytoplasm) before being incorporated into a ribonucleoprotein complex called ______

Drosha Dicer miRISC

What is the source of the dsRNA that is processed to produce siRNA?

Either endogenous or exogenous RNA

In multicellular eukaryotes, what controls the elaboration of sex-related characteristics and behaviors?

Gene regulation

Which statement accurately describes the ability of histone modifying enzymes to bind specific DNA sequences?

Histone modifying enzymes cannot recognize and bind specific DNA sequences on their own.

What is the function of a leucine zipper?

It allows proteins to dimerize with one another.

Each class of small RNA performs its function by forming a ribonucleoprotein complex with a specific member of the Argonaute protein family. What is the role of the small RNA after the complex has formed?

It guides the complex to RNA targets that have perfect or partial complementarity with the small RNA.

What is the function of the Sxl protein?

It regulates the alternative splicing of RNA.

The protein complex that serves as a bridge between RNA polymerase II bound at the promoter and activator or repressor proteins bound at an enhancer is called

Mediator

If gene regulation occurs at the level of translation such that translation is stopped, what molecules in the pathway will NOT be produced?

Phosphorylated protein Protein

A eukaryotic gene can be transcribed at a basal level when ________ ________binds to TBP at the TATA box.

RNA polymerase

A eukaryotic gene can be transcribed at a basal level when_________ _______ binds to TBP at the TATA box.

RNA polymerase

Match each eukaryotic RNA polymerase with the genes that it transcribes.

RNA polymerase I - (Genes encoding the major ribosomal RNAs) RNA polymerase II - (Genes encoding proteins) RNA polymerase III - (Genes encoding tRNAs and some other small RNA molecules)

Which of the following protein domains can be found in repressors?

Repression domain Dimerization domain DNA-binding domain

In fruit flies, transcription of the ______ gene occurs only in XX flies and results in the development of a female animal.

Sxl

In many cells, proteins can exhibit circadian oscillations. In some cases, the amounts of mRNA for these proteins remain constant throughout the day, while the amounts of actual protein produced fluctuate. How can cells achieve that?

The size of the poly-A tails of mRNAs fluctuates during that day, which affects the efficiency of mRNA translation.

How do activators interact with other elements at the promoter to increase transcription levels?

They can directly interact with basal factors. They can indirectly interact with basal factors by binding to mediator.

Select the steps at which gene regulation can occur in eukaryotes.

Transcription Posttranslational modification Translation RNA processing

When a cell divides, most of the histone modifications are lost in the daughter cells. How can daughter cells reestablish their histone modifications?

Transcription factors bind to newly made DNA and recruit histone modifying enzymes.

This diagram shows the addition of A nucleotides to the poly-A tail of an mRNA by the enzyme poly-A polymerase. WIll this affect the translation of the mRNA and if so, how?

Translation will be increased.

Which of the following experimental results would provide evidence that a particular DNA sequence can act as an insulator?

When the DNA sequence is placed between an enhancer and the promoter of a reporter gene, reporter gene expression is blocked.

The development of a fruit fly as male or female is determined by the number of ____ chromosomes that are present.

X

Does the length of the poly-A tail of an mRNA affect the efficiency with which PABP binds to the mRNA and if so, how?

Yes, PABP binds more efficiently to longer poly-A tails.

Which DNA-binding domain is most commonly found in eukaryotic proteins rather than in prokaryotic proteins?

Zinc finger

Corepressor proteins can bind to DNA only when

a repressor with which they can associate is already bound to DNA

The term uORF is used to refer to _____.

a small ORF that encodes a short peptide with no function and is located upstream from the main ORF of an mRNA

Transcription factors that, when bound to an enhancer element, increase transcription of a gene above the basal level, are called transcriptional ____.

activators

The function of a transcription factor can be modulated by ________ interactions with small molecules that bind to the transcription factor.

allosteric

If no enhancer is acting, the presence of a TATA box in the promoter of a gene ______.

allows a low, basal level of transcription

The term for the mechanism that enables two or more different polypeptide sequences to be produced from a single gene is _______ ________.

alternative splicing

Coimmunoprecipitation is a technique that can be used to identify proteins bound to other proteins or to nucleic acids. This is possible because the proteins molecules to which they are bound can be isolated through _____.

antibody binding

Kinase enzymes can increase or decrease the activity of a transcription factor by _____.

attaching a phosphate group to it

The TATA box-binding protein (TBP) is a key component of the ______.

basal factor complex

Most leucine zipper proteins have a characteristic DNA-binding domain called a(n) _______ domain.

basic

In order to be recognized by the small ribosomal subunit, a eukaryotic mRNA is circularized through the interaction of the poly-A ________ ________ and eLF4G

binding protein

The assembly of the basal factor complex at the promoter of a gene is initiated by ____.

binding of the TATA box-binding protein to the promoter

Histone methyltransferases _______.

can act as coactivators or corepressors

Activator proteins often increase transcription through an interaction with ______, proteins that can open local chromatin structure.

coactivators

Histone acetyltransferases can act as transcription factor _________ because they can favor gene expression by acetylating certain lysine residues in histones.

coactivators

In eukaryotic cells, certain histone acetyltransferases can act as ______.

coactivators

In terms of their role in regulating eukaryotic gene expression, histone methyltransferases can act as either _______ or __________ depending on the particular amino acid residue they methylate.

coactivators corepressors

The purification of specific proteins bound to other proteins or nucleic acids through antibody binding is called

coimmunoprecipitation

Small-interfering RNA (siRNA) molecules are produced from _____.

double-stranded RNAs

Activators and repressors are transcription factors that bind to DNA sequence elements called ________.

enhancers

Activators and repressors bind to ______.

enhancers

In yeast, genes can be regulated by upstream activating sequences (UAS). These regulatory elements act in a was similar to _____.

enhancers

The zinc finger motif is typically found in transcription factors in _______ cells, while the helix-turn-helix domain also occurs in transcription factors in __________ cells.

eukaryotic prokaryotic

The Tra protein regulates the splicing of the ______ and ______ primary transcripts.

fru dsx

Which of the following genes encode primary RNAs whose splicing is regulated by the Tra protein?

fru dsx

Some corepressors inhibit transcription by modifying amino acids in the tails of _____ proteins. Other corepressors interact directly with the RNA pol II basal complex and prevent it from binding to the ________.

histone promoter

A regulatory protein that prevents transcription by interfering with the function of activators instead of by recruiting corepressors is called a(n) _________ repressor

indirect

Indirect repressors are regulatory proteins that prevent transcription by

interfering with the function of activators

Indirect repressors are regulatory proteins that prevent transcription by ______.

interfering with the function of activators

The eIF4e binding protein 1 controls translation in response to nutrient availability in eukaryotic cells. When the cell does not have enough nutrients to grow, this protein ______.

is not phosphorylated

Dimerization between two transcription factors can be mediated by a(n) _______ zipper.

leucine

Enhancer sequences can function at a distance from the promoter because the DNA between the enhancer and promoter will _______ to allow basal factors, Mediator, and activators to interact with one another.

loop, bend, or loops

The activity of transcription factor proteins is frequently modulated by the covalent addition of a(n) ___________ group by a kinase enzyme.

phosphate

Corepressors can inhibit transcription by ______.

preventing the RNA pol II basal complex from binding to the promoter modifying amino acids in histone tails

An insulator can be identified by placing the insulator DNA sequence between an enhancer and the _______ of a reporter gene.

promoter

Basal transcription factors bind to ______.

promoter

Activators can increase RNA synthesis by ______.

recruiting basal factors and RNA polymerase II to promoter sequences Need help? Review these concept resources.

When the TATA box-binding protein binds to a gene's promoter, it ______.

recruits other proteins to the promoter

In multicellular eukaryotes, the differentiation of tissues and organs is controlled by gene _______.

regulation

When Dsx-M binds to an enhancer upstream of the yp1 gene, transcription of yp1 is _____. When Dsx-F binds to the same enhancer, transcription of yp1 is _____.

repressed activated

In order for a corepressor protein to associate with an enhancer, a(n) __________ must be bound to the enhancer.

repressor

In yeast cells, an upstream activating sequence (UAS)usually binds _____.

several copies of a single transcription factor

The Sxl protein is an RNA-binding protein that controls the alternative _________ of certain mRNA targets

splicing

Mediator is a protein complex that serves as a bridge between _____.

the basal factor complex and enhancer-binding proteins

The function of a transcription factor may be controlled by _____.

the binding of a small effector molecule

As depicted on the following diagram, an enhancer in loop A cannot interact with a promoter located in loop B. Such loops that form through the activity of insulators are known as ________ __________.

topologically associating

Basal factors, activators, and repressors are collectively known as ________ factors.

transcriptional

A uORF is an open reading frame located ________ from the major ORF of an mRNA. Translation of the uORF generates a small nonfunctional peptide.

upstream