chapter 15

1.

1 point

DNA sites can act:

only in cis

only in trans

either in trans or in cis

2.

1 point

The primary function of basal transcription factors is to:

repress transcription initiation of a particular gene.

assist in associating RNA polymerase with the promoter element.

increase transcription by binding enhancer sequences.

activate RNA synthesis at origins of replication.

regulate activity of DNA polymerase II.

3.

1 point

A philosophic rule that states, “The simplest, most economical explanation is preferable to a more complex one.” is:

Monod and Jacob's rule

Watson and Crick's rule

Occam's razor

operon theory

4.

1 point

How do negative regulators such as the lac repressor prevent RNA polymerase from initiating transcription?

By blocking passage of the polymerase through the operator.

By forming a loop in the operator that restricts the passage of the polymerase.

By physically blocking the DNA binding site of RNA polymerase.

By binding to the polymerase thus preventing its binding.

5.

1 point

How does phage T7 differentially control the transcription of its “early” and “late” genes?

It has two RNA polymerases, each specific for either early or late genes.

The early and late genes have promoters that specify their timing of transcription.

The phage uses the E. coli polymerase to transcribe the early genes, and its own polymerase to transcribe the late genes.

Products of the early genes are actually the inducers of the late genes.

6.

1 point

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

kinase activity

DNA binding

mRNA splicing

DNA replication

methylation

7.

1 point

Most decisions controlling the amount of gene product synthesized are made during:

termination of replication.

transport of mRNA to the cytoplasm.

initiation of transcription.

alternative splicing.

regulation of translation.

8.

1 point

The scientists who proposed the operon theory were:

Monod and Jacob

Watson and Crick

Hardy and Weinberg

Darwin and Mendel

Hershey and Chase

9.

1 point

Which partial diploid strain will produce beta-galactosidase constitutively, and maintain normal induction of the permease and transacetylase?

I+ocZ+Y-A-/I+o+Z-Y+A+

I+o+Z+Y+A+/I+o+Z-Y+A+

I+ocZ-Y+A+/I+ocZ-Y+A+

I+ocZ+Y+A+/I+ocZ-Y+A+

10.

1 point

Transcription in prokaryotes and eukaryotes is similar in that:

transcriptional machinery controls compaction and decompaction of chromatin.

the mRNA produced can undergo alternative splicing.

both prokaryotic and eukaryotic proteins have identical affinities for DNA.

both are contained within the cell nucleus.

both are regulated by attachment of proteins to DNA adjacent to the gene being transcribed.

11.

1 point

Proteins that undergo reversible changes in conformation when bound to another molecule are called:

reversible peptides

allosteric proteins

inducer proteins

repressor proteins

allostatic proteins

12.

1 point

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

beta-galactosidase.

a random region of DNA.

the cis-acting regulatory DNA sequence.

X-gal.

the coding region of the gene being studied.

13.

1 point

What term describes a second level of regulation of the trp operon that occurs in TrpR- mutants suggesting that it is repressor independent?

modulation

derepression

attenuation

amplification

14.

1 point

tRNA molecules are transcribed by:

DNA pol I.

DNA pol II.

DNA pol III.

RNA pol I.

RNA pol II.

RNA pol III.

15.

1 point

In the genotype presented below, what will the expression phenotype for beta-galactoside permease be (I+p+ocZ-Y-A+/I+p+o+Z-Y+A-)?

constitutive

inductive

absent

lethal

16.

1 point

In the trp operon, attenuation occurs through the recognition of two Trp codons in the leader sequence. What would happen if these two codons were mutated to stop codons?

This operon will be insensitive to attenuation by tryptophan.

The structural genes will be transcribed in the presence or absence of tryptophan.

The tryptophan biosynthetic enzymes will be synthesized.

None of these results will take place.

All of these results will take place.

17.

1 point

______________ are cis-acting DNA sequences that often function at a distance from the gene they are regulating.

promoter elements

terminator elements

enhancer elements

regulator elements

initiator elements

18.

1 point

Which statement is true regarding global gene regulation in bacteria?

Sigma factors are not involved in gene regulation, just attachment of the polymerase to the promoter.

Alternative sigma factors recognizing different promoters carry out global gene regulation.

E. coli cells devote more energy to the production of ribosomes during stress so that global gene regulation can occur.

All promoters are recognized by all sigma factors.

19.

1 point

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

RNA polymerase binding region.

TATA box.

initiation site.

TATA box and initiation site only.

RNA polymerase binding region, TATA box, and initiation site

20.

1 point

In the regulation of the trp operon, tryptophan acts as a:

repressor

attenuator

activator

corepressor

operator

21.

1 point

As a general principle of gene regulation through operons regulatory genes encode:

trans-acting proteins that interact with cis-acting DNA elements.

cis-acting proteins that interact with cis-acting DNA elements.

cis-acting proteins that interact with trans-acting DNA elements.

trans-acting proteins that interact with trans-acting DNA elements.

22.

1 point

Mutations introduced into reporter constructs are used to study:

the DNA sequences that are important for regulating gene expression levels.

the effects on cell function of expression of heterologous proteins.

colorimetric assays.

protein-protein interactions.

Western blots.

23.

1 point

RNA polymerase I synthesizes _________ using a DNA template.

dsRNA

mRNA

tRNA

snRNA

rRNA

24.

1 point

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

DNA polymerases.

tumor suppressors.

enhancers.

transcription factors.

promoter elements.

25.

1 point

Catabolic pathways that break down complex substances into more usable units are usually regulated by the:

end products of the pathway.

substrate of an enzyme in the pathway.

other metabolites that are limiting.

none of the above

26.

1 point

In the genotype presented below, what will the expression phenotype for thiogalactoside transacetylase be (I+p+ocZ-Y-A+/I+p+o+Z-Y+A-)?

constitutive

inductive

absent

lethal

27.

1 point

How do positive regulators stimulate initiation of transcription by RNA polymerase?

By allowing passage of the polymerase through the operator.

By binding to the polymerase and increase its ability to initiate transcription.

By causing the helix to unwind in the operator allowing easier initiation.

By making the transcription start site more exposed to the polymerase.

28.

1 point

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

They contain the TATA box regulatory element.

They retain function if their nucleotide sequence is inverted.

They can be more than 10 kilobases from the gene they regulate.

They may increase or decrease gene transcription levels.

They may contain multiple regulatory elements.

29.

1 point

The transition from transcriptional initiation to elongation involves:

binding of sigma factor

release of sigma factor

release of RNA polymerase from DNA

binding of RNA polymerase to DNA

binding of rho factor

30.

1 point

Why is glucose involved in the catabolite repression of the lactose operon?

It has nothing to do with regulation of the lactose operon.

It is produced by the enzymatic breakdown of lactose, its presence thereby signifying the presence of lactose in the cell.

It is also a substrate for beta-galactosidase.

Its presence in the cell increases the amount of lac represor in the cell.

31.

1 point

How are complex processes such as sporulation, synthesis of flagella, and nitrogen fixation that require the transcription of multiple sets of genes regulated in bacteria?

Multiple operons are simultaneously induced.

Cascades of sigma factors synthesized in a temporal order, allow the turning on of successive sets of genes.

The end product of one operon is used as an inducer of the next operon in sequence.

There are single operons consisting of many genes for each of these processes.

32.

1 point

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

associating with regulatory sequences distant from the gene from which they were transcribed.

regulating the expression of the gene from which they were transcribed.

the association of nucleotides with the elongating RNA transcript.

physically associating with DNA polymerase.

regulating the activity of telomerase.

33.

1 point

A single DNA unit that enables the simultaneous regulation of more than one gene in response to environmental changes is called:

promoter

operator

regulator

inducer

operon

34.

1 point

A common amino acid motif found in many of the polypeptides that function as repressors is:

Leucine zipper motif.

Zinc finger motif.

Helix turn helix motif.

Helix loop helix motif.

35.

1 point

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

The reporter gene.

Cis-acting DNA elements.

X-gal coding sequence.

RNA polymerase II gene.

none of the above

36.

1 point

Anabolic pathways involved in the synthesis of essential molecules are usually regulated by:

end product of the pathway.

substrate of the pathway.

other metabolites that are limiting.

none of the above

37.

1 point

_____________ are basal transcription factors that associate with TBP to assist in initiating transcription from eukaryotic class II genes.

TATAs

DNA- BPs

TAFs

Jun and Fos

Sxl and string

38.

1 point

Initiation of transcription by RNA polymerase involved the binding of which of the following subunits to the core enzyme?

delta

sigma

gamma

alpha

zeta

39.

1 point

The __________________________ is the cis-acting DNA sequence that serves as the binding site for RNA polymerase.

promoter

terminator

enhancer

regulator

initiator

40.

1 point

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

cross-reacting

cis-acting

trans-acting

origins of transcription

transcription factors

41.

1 point

In the genotype presented below, what will the expression phenotype for beta-galactosidase be (I+p+ocZ-Y-A+/I+p+o+Z-Y+A-)?

inductive

consitiutive

absent

lethal

42.

1 point

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

initiator

activator

repressor

enhancer

super-repressor

43.

1 point

A reporter gene is:

a protein encoding gene whose expression is easily quantifiable.

often fused to another protein to access its activity.

often fused to another genes' regulatory region to determine control.

all of the above.

none of the above.

44.

1 point

What would be the phenotype of a mutation that altered lac promoter function?

constitutive

inducible

permanently repressed

none of the above

45.

1 point

How does tryptophan, the end product of the trp operon, function in the regulation of the operon?

It binds to the repressor preventing it from binding to DNA thus allowing transcription of the operon.

It binds to the repressor and only then can the repressor bind to DNA allowing transcription of the operon.

It binds directly to DNA and inhibits transcription of the operon.

It binds to the repressor and only then can this complex bind to DNA preventing transcription of the operon.

46.

1 point

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

repressor

activator

promoter

enhancer

initiator

47.

1 point

In E. coli, the heat shock response, switching off the synthesis of some proteins and switching on of different proteins, is mediated by:

inactivation of certain repressor proteins by elevated temperature.

denaturing of DNA in the promoters in the genes of heat sensitive proteins.

synthesis of alternative sigma factors at high temperatures, which then regulate transcription of heat shock genes.

increasing the promoter affinity of already existing polymerase sigma factors at high temperatures.

48.

1 point

The sigma factor that mediates a global heat shock response in E. coli is:

sigma 70

sigma 32

sigma 34

sigma 74

sigma 36

49.

1 point

A common DNA structural feature involved in gene regulatory systems is:

supercoiling of DNA.

looping of the DNA.

unwinding of the double helix.

coiling into Z-DNA.

50.

1 point

The transcription and processing of rRNA molecules takes place in:

the cytoplasm.

Golgi bodies

the nucleolus

the nuclear envelope

ribosomes