QUESTION 12 For each of the following statements, indicate if the statement appl

ID: 58535 • Letter: Q

Question

QUESTION 12

For each of the following statements, indicate if the statement applies only to prokaryotes, only to eukaryotes, or both.

A single RNA polymerase transcribes genes that encode mRNAs, tRNAs, and rRNA.

Transcription of mRNA is blocked by -amanitin.

Sigma () subunit detaches from RNA polymerase shortly after transcription has initiated.

The 5' end of the mature (processed) mRNA begins with a triphosphate.

Typically, the primary mRNA transcript acquires many post-transcriptional modifications before it can be translated.

Typically, mRNAs can be translated while still being transcribed.

prokaryotes

eukaryotes

both

3 points

QUESTION 13

All the following elements can function as eukaryotic promoters except

a TATA box.

CpG islands.

an initiator element.

an enhancer.

3 points

QUESTION 14

The 3’-element closest to the eukaryotic transcription start site is likely to consist of __________ (complete the sentence).

an operator

a TATA box

an enhancer

a promoter proximal element.

3 points

QUESTION 15

Which of the following components is needed for unregulated (basal) RNA transcription?

Pol II and general transcription factors.

Pol II and the mediator protein complex.

Pol II, general transcription factors and the mediator protein complex.

General transcription factors and the mediator protein complex.

3 points

QUESTION 16

Which of the following is not known to be involved in initiation by eukaryotic RNA polymerase II?

DNA helicase activity

DNA polymerase activity

Formation of an open complex

Protein binding to specific DNA sequences

Protein phosphorylation

3 points

QUESTION 17

Which of the following occur(s) during Pol II transcription preinitiation complex formation? (More than one correct answer possible. Mark all that apply).

TFIIB unwinds the DNA.

TFIIA binds to TFIIB.

TFIIB contacts both TATA box-binding factor and the DNA.

DNA bends.

3 points

QUESTION 18

Which of the following is the correct order of binding of general transcription factors to initiate transcription at RNA polymerase II promoters?

TFIID, TFIIH, TFIIB, PolII

TFIID, TFIIB, Pol II, TFIIH

TFIIB, PolII, TFIIH, TFIID

PolII, TFIID, TFIIB, TFIIH

3 points

QUESTION 19

An important early step before transcription initiation that leads to gene expression is

DNA binding by TATA binding protein (TBP).

Rapid packaging of DNA into condensed chromatin assuring the activity of all the genes in eukaryotic cells except those whose transcription is repressed by specific negative regulatory mechanisms.

relief of transcription repression by chromatin remodeling and the removal of neucleosomes to transiently expose promoter DNA.

the coiling of DNA around a set of eight histones in the nucleosome.

3 points

QUESTION 20

An enhancer

is a protein that binds to a promoter and enhances its activity.

is a DNA control element that can be located at a great distance upstream or downstream of a promoter.

acts as a binding site for RNA polymerase.

interacts with repressor proteins to enhance transcriptional repression.

is a protein that binds to RNA polymerase and enhances transcription.

is a DNA element that interacts directly with general transcription factors to enhance or repress transcription.

3 points

QUESTION 21

Are the following components of transcription regulation in eukaryotes cis-acting elements or trans-acting factors?

TATA-box

general transcription factors

enhancer

initiator

mediator

TATA-binding protein

trans-acting factor

cis-acting element

3 points

QUESTION 22

On principle, eukaryotic cells can (and often do) regulate gene expression at any step on the pathway from DNA to protein. Please match six of these steps as marked in Fig 4 with the list below.

mRNA transport and intracellular localization control

posttranslational control

translation control

transcriptional control

mRNA processing control

mRNA degradation control

4 points

QUESTION 23

One major challenge for the eukaryotic transcription machinery not faced by its prokaryotic counterpart is

transcribing complex transcription units into polycistronic mRNA as compared to the simple, typically monocistronic transcription units of prokaryotes.

is unwinding the DNA to allow RNA polyemerase to transcribe the template-strand.

is dealing with the fact that eukaryotic DNA is packaged into neucleosomes and higher-order forms of chromatin structure, while prokaryotic DNA is not.

is the need to engage transcription activators and disengage transcription repressors.

3 points

QUESTION 24

What is the function of TFIIH in the transcription initiation complex?

unwinding the DNA duplex

all are correct

catalyzing the synthesis of RNA

binding to the TATA box

- A. B. C.

A single RNA polymerase transcribes genes that encode mRNAs, tRNAs, and rRNA.