Question 1

If the DNA strand which is complementary to the strand of DNA which is transcribed into RNA has the following base sequence A G C T C A C T G The RNA transcribed would have which of the following sequences?

Accepted Answer

A)   C A G U G A G C U
B)   A G C U C A C U G
C)   A G C T C A C T G
D)   C A G T G A G C U
E)   None of the other answers is correct. B

Question 2

Small nuclear RNAs such as U1, U2 and U5 affect gene expression by

Accepted Answer

A)   diminishing the rate of transcription.
B)   functioning as modified bases within tRNA.
C)   functioning as self-catalytic components of rRNA.
D)   functioning as essential components of the spliceosome.
E)   promoting proper transcription termination. D

Question 3

During RNA synthesis:

Accepted Answer

A)   the DNA template is read 3'_> 5' and RNA is synthesized 5'_> 3'.
B)   the DNA template is read 3'_> 5' and RNA is synthesized 3'_> 5'.
C)   the DNA template is read 5'_> 3' and RNA is synthesized 3'_> 5'.
D)   the DNA template is read 5'_> 5' and RNA is synthesized 5'_> 3'.
E)   none of the above. A

Question 4

Which of the following statements are true only for eukaryotic transcription and processing of mRNA but not for prokaryotic? (1) transcription is regulated by the binding of proteins to specific DNA sequences upstream of the gene.
(2) The RNA is terminated at the 5' end with a cap, consisting of 7-methylguanosine connected by a triphosphate bridge.
(3) RNA polymerase locally melts the DNA strand and copies only the template strand.
(4) Non_coding regions of the RNA transcript are spliced out.
(5) The 3'_terminus of the RNA consists of a long string of A residues (poly A) which are added posttranscriptionally.

Accepted Answer

A)   only 2, 3 and 4 are true
B)   only 3,4 and 5 are true
C)   only 1, 2 and 3 are true
D)   only 2, 4 and 5 are true
E)   only 1, 4 and 5 are true

Question 5

All of the following are known to be typical modifications of RNA after transcription EXCEPT

Accepted Answer

A)   the hydrolytic removal of bases at a few places.
B)   the cleavage of a terminal triphosphate.
C)   hydrolysis to smaller units.
D)   methylation of various bases.
E)   methylation of a hydroxyl group of some ribose units.

Question 6

Which of the following statements about rRNA is correct?

Accepted Answer

A)   rRNA is known to take part in protein synthesis through specific interactions with tRNA.
B)   The cytosol of mammalian cells contains many kinds of 80S ribosomes differing from each other in composition of their RNA.
C)   The bulk of the rRNA is coded for by DNA of nucleoli, an area in which genes or cistrons for rRNA are repeated many times.
D)   rRNA is a small percentage of the total RNA of a cell engaged in protein synthesis.
E)   The major kinds of rRNA of the cytoplasmic ribosomes are all coded for by different unique areas of DNA occurring on different chromosomes.

Question 7

Transcriptionally poised chromatin:

Accepted Answer

A)   Is depleted in methylated CpG dinucleotides.
B)   Is decondensed due to dissociation of histone H1 from the DNA.
C)   Is DNase I sensitive relative to buLIc chromatin.
D)   Is characterized by decreased electrostatic interactions between histones and DNA.
E)   All of the above.

Question 8

Rifampicin inhibits

Accepted Answer

A)   bacterial RNA polymerase.
B)   eukaryotic RNA polymerase II.
C)   both the bacterial and eukaryotic RNA polymerase.
D)   the --> 5' exonuclease activity of DNA polymerase I.

Question 9

The CAPPED 5' end of eukaryotic mRNA

Accepted Answer

A)   consists of poly A sequences.
B)   contains a 5' to 5' link between ribose residues mediated by a triphosphate ester bridge.
C)   is transcribed directly from DNA sequences.
D)   is of NO significance for the activity of mRNA in translation.
E)   is ligated directly adjacent to the AUG codon in mRNA.

Question 10

RNA polymerases in eukaryotic cells

Accepted Answer

A)   are localized in the post-mitochondrial cytoplasmic fraction.
B)   require DNA replication to function.
C)   exist in multiple molecular forms which have different specificities.
D)   require a primer for chain elongation.
E)   polymerize RNA chains in the to 5' direction.

Question 11

Many eukaryotic and some prokaryotic genes have their coding regions interrupted by introns (intervening sequences). These intronic sequences are removed

Accepted Answer

A)   during translation.
B)   from messenger RNA by polyadenylation.
C)   from genomic DNA by nucleases.
D)   from heterogeneous nuclear RNA through a process called splicing.
E)   from transfer RNA by charging which involves amino acids.

Question 12

Transcriptional activator proteins function in the regulation of eukaryotic gene expression by:

Accepted Answer

A)   Mediating the binding of the sigma subunit to RNA polymerase.
B)   Altering the conformation of RNA polymerase.
C)   Binding to specific target sites in chromosomal DNA upstream, within, or downstream of the gene being regulated.
D)   Engaging in protein_protein interactions with core components of the transcription initiation complex.
E)   Both C and D

Question 13

All of the following are true EXCEPT which one?

Accepted Answer

A)   Most eukaryotic RNA never leaves the nucleus.
B)   Essentially all types of eukaryotic RNA undergo post-transcriptional modification.
C)   All forms of RNA are synthesized by some RNA polymerase.
D)   The preferred template of eukaryotic RNA polymerases is double-stranded DNA.
E)   The direction of RNA synthesis is to 5'.

Question 14

Which one of the following statements is true about eukaryotic RNA polymerases?

Accepted Answer

A)   polymerase I is responsible for transcription of ribosomal RNA.
B)   polymerase I is located in the nucleolus.
C)   polymerase III is insensitive to alpha_amanitin.
D)   polymerase II requires sigma factor to initiate RNA synthesis.
E)   polymerase III carries out the splicing of tRNA precursors.

Question 15

Splicing of pre-mRNA introns is accomplished by:

Accepted Answer

A)   hydrolysis of two molecules of ATP.
B)   hydrolysis of two molecules of GTP.
C)   two transesterification reactions.
D)   covalent attachment of guanosine to the 5'_end of the exon.
E)   covalent attachment of the exon to the intron.

Question 16

All of the following statements about the RNA polymerase are true EXCEPT which one?

Accepted Answer

A)   RNA polymerase requires nucleoside triphosphates as substrates.
B)   The 5'-end of the synthesized RNA contains a triphosphate.
C)   The product is covalently linked to the template.
D)   The product is of a specific base sequence dictated by the template.

Question 17

Which of the following is a correct statement about the process of transcription?

Accepted Answer

A)   The process of transcription involves the formation of tRNA, rRNA, as well as mRNA.
B)   transcription starts at a random DNA sequence.
C)   Initiation of transcription is inhibited by actinomycinD.
D)   RNA synthesized is complementary to one of the DNA strands and has the same polarity as the template strand.

Question 18

The following statements are true for all known DNA polymerases. For RNA polymerases, all of the statements are true EXCEPT

Accepted Answer

A)   chain growth is 5' to 3'.
B)   the activated precursors are the triphosphates.
C)   a divalent cation is required.
D)   base pairing instructions are taken from a DNA template.
E)   a primer (pre-existing polynucleotide chain)  is required to initiate synthesis.

Question 19

During mRNA processing, splicing reactions are initiated in the branch site by which reactive group?

Accepted Answer

A)   the 5'-OH of an uridylate residue
B)   the 2'-OH of an adenylate residue
C)   the OH of an adenylate residue
D)   the OH of a guanosine co-factor
E)   the 5'-phosphate of thymidine triphosphate (TTP)

Question 20

In eukaryotes, RNA polymerase II

Accepted Answer

A)   is the most alpha-amanitin resistant polymerase.
B)   is responsible for formation of tRNAs and other small RNAs.
C)   often initiates transcription at complex promoters containing enhancers, silencers and TATA sequences.
D)   terminates RNA synthesis and releases the RNA chain at AATAA sequences specifying end formation and polyadenylation.
E)   normally utilizes bidirectional promoters.

Exam 5: RNA: Transcription and Rna Processing