Question 1

Which of the following does not influence the timing of expression of an operon?

Accepted Answer

A)  Repressors 
B)  Co-repressors 
C)  Presence of substrates of the operon which need to be degraded 
D)  Inducers 
E)  All of these influence the timing of expression 
A)  Repressors 
B)  Co-repressors 
C)  Presence of substrates of the operon which need to be degraded 
D)  Inducers 
E)  All of these influence the timing of expression A

Question 2

Proteins that recognize DNA with specific base sequences are

Accepted Answer

A)  more likely to bind to the major groove. 
B)  more likely to bind to the minor groove. 
C)  equally likely to bind to the major or minor grooves. 
D)  never occur. 
A)  more likely to bind to the major groove. 
B)  more likely to bind to the minor groove. 
C)  equally likely to bind to the major or minor grooves. 
D)  never occur. A

Question 3

Transcription in eukaryotes differs from RNA synthesis in prokaryotes

Accepted Answer

A)  by requiring a primer. 
B)  by simplifying the process with multifunctional enzymes. 
C)  in using more complex s factors. 
D)  by having multiple RNA polymerases rather than one. 
A)  by requiring a primer. 
B)  by simplifying the process with multifunctional enzymes. 
C)  in using more complex s factors. 
D)  by having multiple RNA polymerases rather than one. D

Question 4

As in prokaryotes,the regulatory regions for eukaryotic genes:

Accepted Answer

A)  may be close to the genes they control 
B)  may be upstream of the genes they control 
C)  may be downstream of the genes they control 
D)  All of these are true 
A)  may be close to the genes they control 
B)  may be upstream of the genes they control 
C)  may be downstream of the genes they control 
D)  All of these are true

Question 5

Initiation of RNA biosynthesis involves

Accepted Answer

A)  recognition of the promoter region by the a subunit of RNA polymerase 
B)  conversion of the closed-promoter complex to the open-promoter complex 
C)  binding of one of the a subunits of RNA polymerase to each strand of DNA 
D)  incorporation of four pyrimidine nucleotides in succession 
A)  recognition of the promoter region by the a subunit of RNA polymerase 
B)  conversion of the closed-promoter complex to the open-promoter complex 
C)  binding of one of the a subunits of RNA polymerase to each strand of DNA 
D)  incorporation of four pyrimidine nucleotides in succession

Question 6

At what point does the sigma (s) subunit of RNA polymerase released from the core enzyme?

Accepted Answer

A)  Prior to the incorporation of any nucleotides into an RNA strand. 
B)  After transcription begins and about 10 nucleotides have been added to the RNA chain. 
C)  Just prior to chain termination. 
D)  Never; it is an intrinsic part of the core enzyme. 
A)  Prior to the incorporation of any nucleotides into an RNA strand. 
B)  After transcription begins and about 10 nucleotides have been added to the RNA chain. 
C)  Just prior to chain termination. 
D)  Never; it is an intrinsic part of the core enzyme.

Question 7

Which ends of prokaryotic mRNA are protected from degradation?

Accepted Answer

A)  5' end only 
B)  3' end only 
C)  Both ends 
D)  Neither end 
E)  The RNA is circular and has no ends. 
A)  5' end only 
B)  3' end only 
C)  Both ends 
D)  Neither end 
E)  The RNA is circular and has no ends.

Question 8

Non-coding RNAs are known to:

Accepted Answer

A)  bind to mRNA targeting them for destruction 
B)  bind to mRNA preventing their translation 
C)  promote RNA silencing 
D)  all of these 
A)  bind to mRNA targeting them for destruction 
B)  bind to mRNA preventing their translation 
C)  promote RNA silencing 
D)  all of these

Question 9

What provides the energy for the conversion from the open complex to chain elongation?

Accepted Answer

A)  ATP hydrolysis distinct from any incorporation into the chain. 
B)  Nucleotide hydrolysis associated with incorporation into the chain. 
C)  Torsional stress built into the separating DNA strands. 
D)  Binding of rho (r) factor to the holoenzyme. 
A)  ATP hydrolysis distinct from any incorporation into the chain. 
B)  Nucleotide hydrolysis associated with incorporation into the chain. 
C)  Torsional stress built into the separating DNA strands. 
D)  Binding of rho (r) factor to the holoenzyme.

Question 10

Control of transcription in prokaryotes does not involve

Accepted Answer

A)  enhancers. 
B)  silencers. 
C)  leucine zipper proteins. 
D)  alternative s factors. 
A)  enhancers. 
B)  silencers. 
C)  leucine zipper proteins. 
D)  alternative s factors.

Question 11

Which of the following is not a key step in the activation of mRNA synthesis in eukaryotes?

Accepted Answer

A)  Binding of TBP to the DNA. 
B)  Binding of other transcription factors. 
C)  Binding of RNA Pol I. 
D)  Phosphorylation of the RNA Pol. 
E)  All of these are necessary to initiate RNA synthesis in eukaryotes. 
A)  Binding of TBP to the DNA. 
B)  Binding of other transcription factors. 
C)  Binding of RNA Pol I. 
D)  Phosphorylation of the RNA Pol. 
E)  All of these are necessary to initiate RNA synthesis in eukaryotes.

Question 12

A mutation in the lac A gene would result in

Accepted Answer

A)  continuous production of the proteins encoded by the three structural genes 
B)  continuous production of the lac repressor 
C)  normal operation of the lac operon, but with an alteration in the proteins encoded by the lac A gene 
D)  no transcription from the lac operon 
A)  continuous production of the proteins encoded by the three structural genes 
B)  continuous production of the lac repressor 
C)  normal operation of the lac operon, but with an alteration in the proteins encoded by the lac A gene 
D)  no transcription from the lac operon

Question 13

RNA transcribed from the coding strand instead of the template strand

Accepted Answer

A)  is called antisense RNA. 
B)  produces histones. 
C)  is tRNA. 
D)  never occurs. 
A)  is called antisense RNA. 
B)  produces histones. 
C)  is tRNA. 
D)  never occurs.

Question 14

One rather unusual transcription factor in eukaryotes halts RNA synthesis to allow for repair of damaged DNA.

Accepted Answer

A) True 
 B)False

Question 15

Initiation of transcription in eukaryotes is primarily controlled

Accepted Answer

A)  by two transcription factors 
B)  by keeping the TATA-binding protein physically separated from other transcription factors 
C)  by the order of binding of TFIIA and TFIIB 
D)  in the formation of the preinitiation complex 
A)  by two transcription factors 
B)  by keeping the TATA-binding protein physically separated from other transcription factors 
C)  by the order of binding of TFIIA and TFIIB 
D)  in the formation of the preinitiation complex

Question 16

Ribozymes

Accepted Answer

A)  are more efficient catalysts than protein-based enzymes. 
B)  are involved in protein synthesis. 
C)  always use the same mechanism of catalysis. 
D)  probably evolved later than protein-based enzymes. 
A)  are more efficient catalysts than protein-based enzymes. 
B)  are involved in protein synthesis. 
C)  always use the same mechanism of catalysis. 
D)  probably evolved later than protein-based enzymes.

Question 17

In eukaryotes,which of the following types of RNA undergo some base modification after polymerization of the monomers?

Accepted Answer

A) mRNA 
B) tRNA 
C) rRNA 
D) mRNA and tRNA 
E) mRNA and rRNA
F)all of these 
A) mRNA 
B) tRNA 
C) rRNA 
D) mRNA and tRNA 
E) mRNA and rRNA
F)all of these

Question 18

Which of the following best describes leucine zipper motifs?

Accepted Answer

A)  They allow protein-protein interactions via hydrophobic bonds. 
B)  They allow protein-protein interactions via hydrogen bonds. 
C)  They allow protein-protein interactions via electrostatic interactions. 
D)  They allow protein-DNA interactions by fitting into the major groove of DNA. 
A)  They allow protein-protein interactions via hydrophobic bonds. 
B)  They allow protein-protein interactions via hydrogen bonds. 
C)  They allow protein-protein interactions via electrostatic interactions. 
D)  They allow protein-DNA interactions by fitting into the major groove of DNA.

Question 19

Which of the following correctly describes a difference between RNA & DNA polymerases?

Accepted Answer

A)  RNA polymerases usually do not need a template, while DNA polymerases do. 
B)  DNA polymerases usually require a primer (i.e., they can only continue a strand, not start one), while most RNA polymerases do not. 
C)  RNA polymerases usually synthesize introns, while DNA polymerases synthesize cistrons. 
D)  RNA polymerases polymerize 5' 3', while DNA polymerases polymerize 3' 5'. 
A)  RNA polymerases usually do not need a template, while DNA polymerases do. 
B)  DNA polymerases usually require a primer (i.e., they can only continue a strand, not start one), while most RNA polymerases do not. 
C)  RNA polymerases usually synthesize introns, while DNA polymerases synthesize cistrons. 
D)  RNA polymerases polymerize 5' 3', while DNA polymerases polymerize 3' 5'.

Question 20

Which of the following is true concerning the first nucleotide incorporated into an RNA chain?

Accepted Answer

A)  The first nucleotide incorporated into the RNA chain retains its 5'-triphosphate 
B)  The first nucleotide is always GMP 
C)  The first nucleotide is always cleaved off post-transcriptionally 
D)  The first nucleotide is always modified after transcription 
A)  The first nucleotide incorporated into the RNA chain retains its 5'-triphosphate 
B)  The first nucleotide is always GMP 
C)  The first nucleotide is always cleaved off post-transcriptionally 
D)  The first nucleotide is always modified after transcription

Exam 11: Transcription of the Genetic Code: Biosynthesis of Rna

Which of the following does not influence the timing of expression of an operon?

Proteins that recognize DNA with specific base sequences are

Transcription in eukaryotes differs from RNA synthesis in prokaryotes

As in prokaryotes,the regulatory regions for eukaryotic genes:

Initiation of RNA biosynthesis involves

At what point does the sigma (s) subunit of RNA polymerase released from the core enzyme?

Which ends of prokaryotic mRNA are protected from degradation?

Non-coding RNAs are known to:

What provides the energy for the conversion from the open complex to chain elongation?

Control of transcription in prokaryotes does not involve

Which of the following is not a key step in the activation of mRNA synthesis in eukaryotes?

A mutation in the lac A gene would result in

RNA transcribed from the coding strand instead of the template strand

One rather unusual transcription factor in eukaryotes halts RNA synthesis to allow for repair of damaged DNA.

Initiation of transcription in eukaryotes is primarily controlled

Ribozymes

In eukaryotes,which of the following types of RNA undergo some base modification after polymerization of the monomers?

Which of the following best describes leucine zipper motifs?

Which of the following correctly describes a difference between RNA & DNA polymerases?

Which of the following is true concerning the first nucleotide incorporated into an RNA chain?

Biochemistry and the Organization of Cells

Water: The Solvent for Biochemical Reactions

Amino Acids and Peptides

The Three-Dimensional Structure of Proteins

Protein Purification and Characterization Techniques

The Behavior of Proteins: Enzymes

The Behavior of Proteins: Enzymes, Mechanisms, and Control

Lipids and Proteins Are Associated in Biological Membranes

Nucleic Acids: How Structure Conveys Information

Biosynthesis of Nucleic Acids: Replication

Protein Synthesis: Translation of the Genetic Message

Nucleic Acid Biotechnology Techniques

Viruses, Cancer, and Immunology

The Importance of Energy Changes and Electron Transfer in Metabolism

Carbohydrates

Glycolysis

Storage Mechanisms and Control in Carbohydrate Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Lipid Metabolism

Photosynthesis

The Metabolism of Nitrogen

Integration of Metabolism: Cellular Signaling

Filters