Deck 16: Gene Regulation in Eukaryotes

Question 1

A transcription factor that increases initiation of transcription by associating with an enhancer element is termed a(n)

A)initiator.
B)activator.
C)repressor.
D)enhancer.
E)super-repressor.

Answer 1

activator.

Question 2

Proteins that consist of two identical polypeptide subunits are classified as

A)monomers.
B)oligomers.
C)heterodimers.
D)homodimers.
E)diplomers.

Answer 2

homodimers.

Question 3

What is the name for the basal transcription factors that associate with TBP to assist in initiating transcription from eukaryotic class II genes?

A)TATAs
B)DNA- BPs
C)TAFs
D)Jun and Fos
E)Sxl and string

Answer 3

TAFs

Question 4

What is the name of the cis-acting DNA sequence that serves as the binding site for the transcriptional initiation complex?

A)Promoter
B)Terminator
C)Enhancer
D)Regulator

Question 5

In generating a reporter construct to study gene regulation, the reporter gene introduced replaces

A) $\beta$ -galactosidase.
B)a random region of DNA.
C)the cis-acting regulatory DNA sequence.
D)X-gal.
E)the coding region of the gene being studied.

Question 6

The promoter of nearly all eukaryotic genes contains a(n)

A)RNA polymerase binding region.
B)TATA box.
C)initiation site.
D)TATA box and initiation site.
E)RNA polymerase binding region, TATA box, and initiation site.

Question 7

The primary function of basal transcription factors is to

A)repress transcription initiation of a particular gene.
B)assist in associating RNA polymerase with the promoter element.
C)increase transcription by binding enhancer sequences.
D)activate RNA synthesis at origins of replication.
E)regulate activity of DNA polymerase II.

Question 8

What is name of the motifs that function to promote the DNA-binding activity of many transcriptional activator proteins?

A)ABP
B)Zinc finger
C)Basolateral
D)Leucine zipper
E)Medial cleft

Question 9

Trans-acting proteins that influence transcription are commonly referred to as

A)DNA polymerases.
B)tumor suppressors.
C)enhancers.
D)transcription factors.
E)promoter elements.

Question 10

Which of the following is NOT true of enhancer DNA sequences?

A)They contain the TATA box regulatory element.
B)They retain function if their nucleotide sequence is inverted.
C)They can be more than 10 kilobases from the gene they regulate.
D)They may increase or decrease gene transcription levels.
E)They may contain multiple regulatory elements.

Question 11

The gene products encoded by trans-acting elements perform their function by

A)associating with regulatory sequences distant from the gene from which they were transcribed.
B)regulating the expression of the gene from which they were transcribed.
C)the association of nucleotides with the elongating RNA transcript.
D)physically associating with DNA polymerase.
E)regulating the activity of telomerase.

Question 12

A cis-acting DNA sequence that modulates the basal rate of transcription of a gene is termed a(n)

A)repressor.
B)activator.
C)promoter.
D)enhancer.
E)initiator.

Question 13

What does RNA polymerase I synthesize?

A)dsRNA
B)mRNA
C)tRNA
D)snRNA
E)rRNA

Question 14

The primary point of control for most genes for the amount of gene product synthesized is

A)termination of replication.
B)transport of mRNA to the cytoplasm.
C)initiation of transcription.
D)alternative splicing.
E)regulation of translation.

Question 15

Transcription in prokaryotes and eukaryotes is similar in that

A)transcriptional machinery controls compaction and decompaction of chromatin.
B)the mRNA produced can undergo alternative splicing.
C)both prokaryotic and eukaryotic proteins have identical affinities for DNA.
D)both are contained within the cell nucleus.
E)both are regulated by attachment of proteins to DNA adjacent to the gene being transcribed.

Question 16

Mutations altering the amount of protein synthesized from a reporter construct occur most often in which of the following sequences of DNA?

A)the reporter gene
B)cis-acting DNA elements
C)X-gal coding sequence
D)RNA polymerase II gene
E)None of the choices is correct.

Question 17

DNA sequences that serve as binding sites for proteins regulating transcription and are often found adjacent to a gene are said to be

A)cross-reacting.
B)cis-acting.
C)trans-acting.
D)origins of transcription.
E)transcription factors.

Question 18

Zinc-finger peptide motifs are responsible for what aspect of protein function?

A)Kinase activity
B)DNA binding
C)mRNA splicing
D)DNA replication

Question 19

tRNA molecules are transcribed by

A)DNA pol II.
B)DNA pol III.
C)RNA pol I.
D)RNA pol II.
E)RNA pol III.

Question 20

What is the term for the cis-acting DNA sequences that often function at a distance from the gene they are regulating?

A)Promoter elements
B)Terminator elements
C)Enhancer elements
D)Regulator elements
E)Initiator elements

Question 21

Which of the following is NOT a mechanism employed by repressor proteins to decrease transcription of a specific gene?

A)The repressor associates with a promoter element, blocking RNA polymerase from binding promoter element.
B)The repressor binds to the activation domain of an activator, eliminating its ability to increase transcription.
C)The repressor binds to DNA-binding domain of an activator, eliminating its ability to associate with enhancer.
D)The repressor binds to a DNA sequence in an enhancer, eliminating access to sequence by activator.
E)The repressor binds to RNA polymerase II, blocking its ability to associate with promoter element.

Question 22

What is the relationship between methylation and genomic imprinting?

A)Differential methylation of alleles in males and females resuilts in only one of the parental alleles being transcriptionally active in the offspring.
B)Methylation of alleles silences the alleles from both parents, no alleles are transcriptionally active.
C)Reversible methylation in the males alleles results in the males alleles only being expressed late in development.
D)Reversible methylation in the females alleles results in the females alleles only being expressed late in development.

Question 23

The leucine zipper motif functions to

A)mediate the physical association of two polypeptides.
B)anchor transcriptional activator proteins to enhancer sequences.
C)release leucines from misfolded transcription factors.
D)integrate leucines and isoleucines into newly translated transcriptional activators.
E)open up proteins after transcription.

Question 24

What is the term for transcription factors that decrease transcriptional activity by associating with specific enhancer elements or activator proteins?

A)Deregulators
B)Depleters
C)Regulators
D)Repressors
E)TBPs

Question 25

What is the term used to describe a situation in which a gene's expression pattern is dependent upon the parent from which it was inherited?

A)Genomic imprinting
B)Spermatogenesis
C)Heterodimerization
D)Homodimerization
E)Gender-specific RNA stability

Question 26

DNA regions that are transcriptionally silenced by hypercondensation have often undergone a modification of their cytosine residues termed

A)hyperoxidation.
B)methylation.
C)dephosphorylation.
D)phosphorylation.
E)integration.

Question 27

How can one primary mRNA result in several polypeptrides with differnt amino acid sequences?

A)Alternative splicing of exons and introns.
B)Post-translational modification such as phosphorylation.
C)Pre-translational modification such as phosphorylation.
D)Modification of the mature mRNA by phosphorylation

Question 28

In regards to Dropsophila sex determination how does the number of X chromosomes affect the cell?

A)The SxI promoter is responsive to levels of transcription factors produced from genes on the X chrpomosome.
B)The SxI promoter is responsive to levels of transcription factors produced from genes on the Y chrpomosome.
C)The X chromosome produces a single transcription factor that results in a male if at a low concentration and a female in a high concentration
D)The SxI promoter is repressed by levels of transcription factors thata re produced from genes on the X chromosome.

Question 29

The ChIP technique can be used to identify putative DNA binding sites for various transcription factors since it

A)identifies DNA sequences bound to specific proteins.
B)identifies all sites bound by proteins in the nucleus.
C)identifies the size of different protein-DNA complexes.
D)indetifies proteins that can interact with mRNA.

Question 30

What is the term for the repeating structural unit of chromatin, consisting of approximately 200 base pairs of DNA and associated histone proteins?

A)Transcriptosome
B)Regulosome
C)Nucleosome
D)Enhanceosome

Question 31

The association of DNA with histones to form chromatin affects transcription by

A)increasing basal transcription rates.
B)decreasing basal transcription rates.
C)increasing transcription of a few genes, while not influencing most others.
D)decreasing transcription of a few genes, while not influencing most others.
E)increasing transcription of some genes and decreasing transcription of others.

Question 32

Which small RNA is involved in the silencing of transposable element transcription?

A)miRNA
B)siRNA
C)Piwi
D)tRNA

Question 33

In Drosophila females, Sxl protein associates with RNA alters the splicng pattern of the transcripts from which gene?

A)sax
B)max
C)sxl
D)myc
E)SIR

Question 34

Hypercondensation of heterochromatin results in

A)hyperactivation of transcription.
B)suppression of progression through metaphase.
C)DNA replication.
D)transcriptional silencing.
E)None of the choices is correct.

Question 35

A variation that does not involve a change in DNA sequence but can be passed from one generation to another is a(n)

A)enhancer trap.
B)replication origin.
C)Mendelian enhancer.
D)mutant chromosome.
E)epigenetic phenomenon.

Question 36

Recessive mutations in the sxl gene in Drosophila are lethal in XX females because

A)sxl functions as a repressor of a male-specific dosage-compensation gene.
B)recessive mutations indicate an increase in sxl activity.
C)these mutations are the result of a loss of both X chromosomes.
D)sxl is required for transcription of male-specific genes.
E)recessive mutations are always lethal.

Question 37

Insulators act to

A)interfere with the action of enhancer-activator complexes with specific promoters.
B)remodel chromatin structure.
C)bind with repressors.
D)bind with transcription factors that are activators.

Question 38

Enhancers can be identified by

A)cloning a region of DNA with the putative enhancer in a reporter plasmid and demonstrating an increase in gene expression when the construct is introduced into a eukaryotic cell..
B)sequence comparison with promoter sequences that are already known.
C)introducing two seperate pieces of DNA into a eukaryotic cell.One is a fragment of DNA with the putative enhancer and the other is a plasmid that contains a reporter gene.
D)cloning the putative enhancer into a plasmid and measuring the level of reporter gene expression in a prokaryotic cell.

Question 39

How is sex determined in Drosophila?

A)Alternative splicing of SxI in females results in an active transcription factor that in turn results in the production of tra..
B)Alternative splicing of SxI in females results in an inactive transcription factor that in turn results in the production of tra.
C)The Y chromosome has 4 genes for different transcription factors that control the splicing of SxI.
D)The Y chromosome has 4 genes for different transcription factors that control the transcription of SxI.