Question 1

All of the following statements about ribosomes are correct EXCEPT which one?

Accepted Answer

A)   All ribosomes have two subunits, the large subunit approximately twice the size of the smaller subunit.
B)   Eukaryotic cells have 80S ribosomes, and protein synthesis on these ribosomes can be inhibited by cycloheximide.
C)   Prokaryotic cells have 70S ribosomes, and protein synthesis on these ribosomes can be inhibited by chloramphenicol.
D)   Mitochondria have 80S ribosomes, and protein synthesis on these ribosomes can be inhibited by cycloheximide.
E)   The larger subunits of all ribosomes have the enzyme peptidyl transferase which forms peptide bonds.

Question 2

The nucleosome is the basic repeating unit of chromatin. Which of the following statements concerning nucleosomes is incorrect?

Accepted Answer

A)   Nucleosomes have protein cores consisting of an octamer of protein subunits.
B)   A segment of DNA approximately 145 bp long is associated with each nucleosome.
C)   Histone H1 contacts the DNA linker segments as they enter and leave the nucleosome.
D)   The DNA in a nucleosome is packed tightly inside the protein core to conserve space in the nucleus and to protect the DNA from damage.
E)   Some nucleosomes form over specific regions of DNA in a non-random manner.

Question 3

The precursor for an RNA that contains a codon (near its 5' end)  corresponding to an N_terminal amino acid in a protein is

Accepted Answer

A)   messenger RNA.
B)   heterogeneous nuclear RNA.
C)   transfer RNA.
D)   ribosomal RNA.
E)   small nuclear RNA.

Question 4

In what part of the mammalian cell is ribosomal RNA produced?

Accepted Answer

A)   Endoplasmic reticulum
B)   Mitochondrion
C)   Nucleolus
D)   Golgi apparatus

Question 5

All of the following statements are correct with regard to multiple RNA polymerases of eukaryotic cells EXCEPT

Accepted Answer

A)   different polymerases may have certain subunits in common.
B)   polymerases I and II can be distinguished from one another in vitro by differential sensitivity to alpha-amanitin.
C)   polymerase II synthesizes 45S rRNA precursors.
D)   polymerase III synthesizes 5S RNA.
E)   polymerase I is localized in the nucleolus.

Question 6

In a comparison of typical eukaryotic and prokaryotic mRNA, all of the following are true EXCEPT

Accepted Answer

A)   the termini at the 5' end differ.
B)   the termini at the end differ.
C)   both contain regions which are not translated.
D)   both may be translated before transcription is completed.
E)   AUG is an initiation codon for translation in both.

Question 7

All of the following activities are involved in the processing of RNA EXCEPT

Accepted Answer

A)   endonuclease cleavage.
B)   primer excision.
C)   addition of 5' cap.
D)   exonuclease cleavage.
E)   base modification.

Question 8

Which of the following is a characteristic of transcription?

Accepted Answer

A)   A short primer, complementary to the DNA template, is required to initiate transcription.
B)   ATP serves as the energy requirement for each new phosphodiester bond.
C)   The reaction is driven toward product formation by hydrolysis of pyrophosphate.
D)   The coding information is contained within the RNA polymerase.
E)   The reaction is semi-conservative with respect to the DNA template.

Question 9

The two largest rRNA molecules are formed

Accepted Answer

A)   by partial degradation of a single, large RNA molecule.
B)   on two separate genomes.
C)   by condensation of two or more mRNA species.
D)   by translation of mRNA.

Question 10

An intervening sequence is

Accepted Answer

A)   more stable than coding sequences during evolution.
B)   found only in beta and delta genes of globin.
C)   absent or lacking in some eukaryotic genes.
D)   always A-T rich.
E)   always shorter than that of a coding sequence.

Question 11

During splicing of pre-mRNA:

Accepted Answer

A)   the energy requirement for phosphodiester formation is supplied by the spliceosome.
B)   each new phosphodiester bond requires hydrolysis of one molecule of ATP.
C)   each new phosphodiester bond requires hydrolysis of one molecule of GTP.
D)   phosphodiester bonds are hydrolyzed and new bonds are formed subsequently by ligation.
E)   the number of phosphodiester bonds remains constant.

Question 12

Synthesis of mRNA

Accepted Answer

A)   in eukaryotes involves more enzymes than in prokaryotes.
B)   starts at the same initiation codons used during protein synthesis.
C)   in prokaryotes involves a different RNA polymerase than is used for tRNA synthesis.
D)   stops at the same termination codons used during protein synthesis.
E)   Both B and D are true.

Question 13

Which of the following would result in an increase in the extent of heteroduplex formation in general genetic recombination?

Accepted Answer

A)   resolution
B)   isomerization
C)   branch migration
D)   base unstacking
E)   D loop degradation

Question 14

The antibiotic rifampicin (Rifamycin B)  inhibits transcription by:

Accepted Answer

A)   binding the promoter to block association of RNA polymerase with the template.
B)   binding RNA polymerase B_subunit to block transcription initiation.
C)   binding sigma factor, thereby altering promoter specificity.
D)   promoting spontaneous hydrolysis of newly synthesized phosphodiester bonds.
E)   inhibiting translation, which is required for coupled transcription/translation in prokaryotes.

Question 15

Regarding posttranscriptional processing of mRNA molecules in eukaryotic cells, which of the following statements is correct?

Accepted Answer

A)   A poly A sequence is added to the 5' end of the newly formed hnRNA.
B)   Introns are nontranslated regions of hnRNA which are excised during processing.
C)   The capping of hnRNA, unlike other processing events, occurs in the cytoplasm of cells.
D)   Both A and B are correct.
E)   Both B and C are correct.

Question 16

All of the following statements related to RNA polymerase from Escherichia coli are true EXCEPT

Accepted Answer

A)   it contains multiple subunits.
B)   it is able to separate DNA strands.
C)   the sigma subunit is responsible for specific binding to DNA.
D)   the core enzyme is sufficient for elongation.
E)   it contains rho factor as a subunit.

Question 17

Production of a eukaryotic mRNA may involve all of the following EXCEPT

Accepted Answer

A)   removal of introns and splicing.
B)   capping of the 5' terminus.
C)   addition of poly A at the terminus.
D)   removal of intervening sequences by DNA gyrase.

Question 18

All of the following statements concerning mRNA are true EXCEPT which one?

Accepted Answer

A)   RNA polymerase II is responsible for mRNA synthesis.
B)   The initial transcription product is a high molecular weight precursor termed heterogeneous nuclear RNA.
C)   mRNA contains a cap structure at its 5' end but hnRNA does not.
D)   The leader sequence at the 5' end of the mRNA molecule does not code for any amino acids.
E)   Both hnRNA and mRNA contain poly(
A)   at their termini.

Question 19

Capping of prokaryotic monocistronic mRNA's allows correct translation in a eukaryotic translation system. This result is evidence for

Accepted Answer

A)   a role for 7-methyl-GpppNp in the recognition of mRNA by eukaryotic initiation factors and/or ribosomes.
B)   a role for poly A in mRNA selection.
C)   a role for F-met-tRNA in protein recognition.
D)   a malfunctioning prokaryotic RNA-polymerase.
E)   the production of monocistronic mRNA's in eukaryotes.

Question 20

RNA splicing involves

Accepted Answer

A)   the removal of exons.
B)   the assembly of ribosomes.
C)   transcription initiation factors.
D)   the removal of introns.
E)   DNA rearrangements.

Exam 5: RNA: Transcription and Rna Processing

All of the following activities are involved in the processing of RNA EXCEPT

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During splicing of pre-mRNA:

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Which of the following would result in an increase in the extent of heteroduplex formation in general genetic recombination?

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The two largest rRNA molecules are formed

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The precursor for an RNA that contains a codon (near its 5' end) corresponding to an N_terminal amino acid in a protein is

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RNA splicing involves

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Regarding posttranscriptional processing of mRNA molecules in eukaryotic cells, which of the following statements is correct?

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Which of the following is a characteristic of transcription?

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The nucleosome is the basic repeating unit of chromatin. Which of the following statements concerning nucleosomes is incorrect?

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In a comparison of typical eukaryotic and prokaryotic mRNA, all of the following are true EXCEPT

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All of the following statements are correct with regard to multiple RNA polymerases of eukaryotic cells EXCEPT

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All of the following statements related to RNA polymerase from Escherichia coli are true EXCEPT

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An intervening sequence is

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Production of a eukaryotic mRNA may involve all of the following EXCEPT

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Capping of prokaryotic monocistronic mRNA's allows correct translation in a eukaryotic translation system. This result is evidence for

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All of the following statements concerning mRNA are true EXCEPT which one?

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All of the following statements about ribosomes are correct EXCEPT which one?

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The antibiotic rifampicin (Rifamycin B) inhibits transcription by:

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In what part of the mammalian cell is ribosomal RNA produced?

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Synthesis of mRNA

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