Question 1

Which statement is CORRECT with respect to $\rho$(rho)-dependent termination of RNA synthesis?

Accepted Answer

A)  Self-complementary GC sequences act as signals for transcriptional termination. 
B)  Formation of a hairpin structure disrupts DNA duplex formation and facilitates dissociation of the transcript. 
C)  ATP is hydrolyzed as part of the termination process. 
D)  Transcripts are terminated at specific residues in the sequence. 
E)  Transcripts terminate immediately at rut sites. 
A)  Self-complementary GC sequences act as signals for transcriptional termination. 
B)  Formation of a hairpin structure disrupts DNA duplex formation and facilitates dissociation of the transcript. 
C)  ATP is hydrolyzed as part of the termination process. 
D)  Transcripts are terminated at specific residues in the sequence. 
E)  Transcripts terminate immediately at rut sites.

Question 2

After binding by E. coli RNA polymerase, the CORRECT order of events for transcription initiation is:

Accepted Answer

A)  closed complex formation, open complex formation, promoter clearance, start of RNA synthesis. 
B)  closed complex formation, open complex formation, start of RNA synthesis, promoter clearance. 
C)  open complex formation, closed complex formation, start of RNA synthesis, promoter clearance. 
D)  start of RNA synthesis, closed complex formation, open complex formation, promoter clearance. 
E)  start of RNA synthesis, open complex formation, closed complex formation, promoter clearance. 
A)  closed complex formation, open complex formation, promoter clearance, start of RNA synthesis. 
B)  closed complex formation, open complex formation, start of RNA synthesis, promoter clearance. 
C)  open complex formation, closed complex formation, start of RNA synthesis, promoter clearance. 
D)  start of RNA synthesis, closed complex formation, open complex formation, promoter clearance. 
E)  start of RNA synthesis, open complex formation, closed complex formation, promoter clearance.

Question 3

Synthesis and maturation of tRNA does NOT require which process?

Accepted Answer

A)  transcription of a gene 
B)  RNaseD cleavage 
C)  RNaseP cleavage 
D)  addition of CCA to the 5' end of the molecule 
E)  methylation of specific bases 
A)  transcription of a gene 
B)  RNaseD cleavage 
C)  RNaseP cleavage 
D)  addition of CCA to the 5' end of the molecule 
E)  methylation of specific bases

Question 4

Which statement about $\rho$-independent termination of RNA transcription in E. coli is TRUE?

Accepted Answer

A)  The RNA transcript contains self-complementary sequences. 
B)  There are three conserved A's in the template strand near the end of the transcript. 
C)  There is a CA-rich sequence near the end of the transcript. 
D)  The RNA transcript contains self-complementary sequences, and there are three conserved A's in the template strand near the end of the transcript. 
E)  The RNA transcript contains self-complementary sequences, and there is a CA-rich sequence near the end of the transcript. 
A)  The RNA transcript contains self-complementary sequences. 
B)  There are three conserved A's in the template strand near the end of the transcript. 
C)  There is a CA-rich sequence near the end of the transcript. 
D)  The RNA transcript contains self-complementary sequences, and there are three conserved A's in the template strand near the end of the transcript. 
E)  The RNA transcript contains self-complementary sequences, and there is a CA-rich sequence near the end of the transcript.

Question 5

Which groups act as nucleophiles in the splicing of group I introns?

Accepted Answer

A)  2' OH groups only 
B)  3' OH groups only 
C)  5´ OH groups only 
D)  both 2' and 5'OH groups 
E)  both 3'and 5' OH groups 
A)  2' OH groups only 
B)  3' OH groups only 
C)  5´ OH groups only 
D)  both 2' and 5'OH groups 
E)  both 3'and 5' OH groups

Question 6

Which statement about E. coli RNA polymerase (core enzyme) is FALSE?

Accepted Answer

A)  It can start new chains de novo or elongate old ones. 
B)  It has no catalytic activity unless the sigma factor is bound. 
C)  It uses nucleoside 5'-triphosphates as substrates. 
D)  Its activity is blocked by rifampicin. 
E)  Its RNA product will hybridize with the DNA template. 
A)  It can start new chains de novo or elongate old ones. 
B)  It has no catalytic activity unless the sigma factor is bound. 
C)  It uses nucleoside 5'-triphosphates as substrates. 
D)  Its activity is blocked by rifampicin. 
E)  Its RNA product will hybridize with the DNA template.

Question 7

Rifampicin blocks RNA polymerase; why would this be lethal to a cell that was sensitive to this drug?

Accepted Answer

Rifampicin is an antibiotic that specifi

Question 8

Describe all of the known catalytic activities of reverse transcriptase.

Accepted Answer

Reverse transcriptase is an enzyme that

Question 9

Compared with DNA polymerase, reverse transcriptase:

Accepted Answer

A)  does not require a primer to initiate synthesis. 
B)  introduces no errors into genetic material because it synthesizes RNA, not DNA. 
C)  makes fewer errors in synthesizing a complementary polynucleotide. 
D)  makes more errors because it lacks the 3' $\rightarrow$ 5' proofreading exonuclease activity. 
E)  synthesizes complementary strands in the opposite direction-from 3' $\rightarrow$  5'. 
A)  does not require a primer to initiate synthesis. 
B)  introduces no errors into genetic material because it synthesizes RNA, not DNA. 
C)  makes fewer errors in synthesizing a complementary polynucleotide. 
D)  makes more errors because it lacks the 3' $\rightarrow$ 5' proofreading exonuclease activity. 
E)  synthesizes complementary strands in the opposite direction-from 3' $\rightarrow$  5'.

Question 10

Which statement is TRUE regarding topoisomerases during synthesis of nucleic acids by E. coli RNA polymerase?

Accepted Answer

A)  DNA gyrase is required to relieve supercoils on the DNA exit side of the polymerase. 
B)  Since no strand cleavage occurs, supercoiling is not a factor in the action of RNA polymerase. 
C)  Positive supercoils are generated ahead of the transcription bubble. 
D)  Both the DNA and the RNA product will be supercoiled. 
E)  None of the statements is true. 
A)  DNA gyrase is required to relieve supercoils on the DNA exit side of the polymerase. 
B)  Since no strand cleavage occurs, supercoiling is not a factor in the action of RNA polymerase. 
C)  Positive supercoils are generated ahead of the transcription bubble. 
D)  Both the DNA and the RNA product will be supercoiled. 
E)  None of the statements is true.

Question 11

What do retrovirus reverse transcriptases use to initiate DNA synthesis?

Accepted Answer

A)  They can synthesize DNA without a primer. 
B)  They require the action of cellular primase. 
C)  They contain a primase activity. 
D)  They use a tRNA molecule as a primer. 
E)  None of these is used by reverse transcriptases in initiation of DNA synthesis. 
A)  They can synthesize DNA without a primer. 
B)  They require the action of cellular primase. 
C)  They contain a primase activity. 
D)  They use a tRNA molecule as a primer. 
E)  None of these is used by reverse transcriptases in initiation of DNA synthesis.

Question 12

Why did the "RNA World" hypothesis have to await the discovery of ribozymes in order to become a widely attractive scenario?

Accepted Answer

The "RNA World" hypothesis posits that e

Question 13

AZT is one drug used as an HIV inhibitor. How does its structure differ from thymidine?

Accepted Answer

A)  The aromatic ring in AZT is not methylated at the 5 position. 
B)  An azido group is present at C-2' in AZT. 
C)  An azido group is present at C-3' in AZT. 
D)  The 5' OH is methylated in AZT. 
E)  The aromatic ring is amidated at the 4 position. 
A)  The aromatic ring in AZT is not methylated at the 5 position. 
B)  An azido group is present at C-2' in AZT. 
C)  An azido group is present at C-3' in AZT. 
D)  The 5' OH is methylated in AZT. 
E)  The aromatic ring is amidated at the 4 position.

Question 14

Which step is NOT a part of the synthesis of a 5' mRNA cap?

Accepted Answer

A)  conversion of a 5'triphosphate into a 5F1' diphosphate 
B)  formation of a 5' to 5'phosphodiester bond 
C)  methylation of 2' OH groups 
D)  transfer of a GMP group onto a nucleic acid 
E)  All of these steps are part of 5' cap synthesis. 
A)  conversion of a 5'triphosphate into a 5F1' diphosphate 
B)  formation of a 5' to 5'phosphodiester bond 
C)  methylation of 2' OH groups 
D)  transfer of a GMP group onto a nucleic acid 
E)  All of these steps are part of 5' cap synthesis.

Question 15

Which process is NOT part of the processing of the 30S pre-rRNA transcript?

Accepted Answer

A)  addition of a poly(
A)  tail 
B)  methylation of bases 
C)  conversion of uridine to pseudoiuridine 
D)  conversion of uridine to dihydrouridine 
E)  hydrolysis by RNase P 
A)  addition of a poly(
A)  tail 
B)  methylation of bases 
C)  conversion of uridine to pseudoiuridine 
D)  conversion of uridine to dihydrouridine 
E)  hydrolysis by RNase P

Question 16

In eukaryotes, RNA polymerase II:

Accepted Answer

A)  is a multisubunit protein with subunits that are homologous to E. coli RNAP. 
B)  is associated with transcription of mRNA and rRNA. 
C)  is found in chloroplasts and mitochondria. 
D)  includes a small protein subunit that is phosphorylated during elongation. 
E)  All of the answers are correct. 
A)  is a multisubunit protein with subunits that are homologous to E. coli RNAP. 
B)  is associated with transcription of mRNA and rRNA. 
C)  is found in chloroplasts and mitochondria. 
D)  includes a small protein subunit that is phosphorylated during elongation. 
E)  All of the answers are correct.

Question 17

Which activity is NOT associated with retrovirus reverse transcriptases?

Accepted Answer

A)  RNA-dependent DNA synthesis 
B)  synthesis of RNA primers 
C)  RNA degradation 
D)  DNA-dependent DNA synthesis 
E)  All of these are associated with reverse transcriptase. 
A)  RNA-dependent DNA synthesis 
B)  synthesis of RNA primers 
C)  RNA degradation 
D)  DNA-dependent DNA synthesis 
E)  All of these are associated with reverse transcriptase.

Question 18

"Footprinting," or DNase protection, is a technique used to identify:

Accepted Answer

A)  a region of DNA that has been damaged by mutation. 
B)  E. coli cells that contain a desired, cloned piece of DNA. 
C)  the position of a particular gene of a chromosome. 
D)  the position of internally double-stranded regions in a single-stranded DNA molecule. 
E)  the specific binding site of a repressor, polymerase, or other protein on the DNA. 
A)  a region of DNA that has been damaged by mutation. 
B)  E. coli cells that contain a desired, cloned piece of DNA. 
C)  the position of a particular gene of a chromosome. 
D)  the position of internally double-stranded regions in a single-stranded DNA molecule. 
E)  the specific binding site of a repressor, polymerase, or other protein on the DNA.

Question 19

In the synthesis of cDNA libraries for eukaryotic genes, reverse transcriptase can be used with a primer containing poly(T). Why is this NOT useful for prokaryotic systems?

Accepted Answer

In the synthesis of cDNA libraries for e

Question 20

Describe the sequence of events in the initiation of transcription by E. coli RNA polymerase.

Accepted Answer

The initiation of transcription by E. co

Exam 26: RNA Metabolism

Which statement is CORRECT with respect to ρ\rhoρ (rho)-dependent termination of RNA synthesis?

After binding by E. coli RNA polymerase, the CORRECT order of events for transcription initiation is:

Synthesis and maturation of tRNA does NOT require which process?

Which statement about ρ\rhoρ -independent termination of RNA transcription in E. coli is TRUE?

Which groups act as nucleophiles in the splicing of group I introns?

Which statement about E. coli RNA polymerase (core enzyme) is FALSE?

Rifampicin blocks RNA polymerase; why would this be lethal to a cell that was sensitive to this drug?

Describe all of the known catalytic activities of reverse transcriptase.

Compared with DNA polymerase, reverse transcriptase:

Which statement is TRUE regarding topoisomerases during synthesis of nucleic acids by E. coli RNA polymerase?

What do retrovirus reverse transcriptases use to initiate DNA synthesis?

Why did the "RNA World" hypothesis have to await the discovery of ribozymes in order to become a widely attractive scenario?

AZT is one drug used as an HIV inhibitor. How does its structure differ from thymidine?

Which step is NOT a part of the synthesis of a 5' mRNA cap?

Which process is NOT part of the processing of the 30S pre-rRNA transcript?

In eukaryotes, RNA polymerase II:

Which activity is NOT associated with retrovirus reverse transcriptases?

"Footprinting," or DNase protection, is a technique used to identify:

In the synthesis of cDNA libraries for eukaryotic genes, reverse transcriptase can be used with a primer containing poly(T). Why is this NOT useful for prokaryotic systems?

Describe the sequence of events in the initiation of transcription by E. coli RNA polymerase.

The Foundations of Biochemistry

Water

Amino Acids, Peptides, and Proteins

The Three-Dimensional Structure of Proteins

Protein Function

Enzymes

Carbohydrates and Glycobiology

Nucleotides and Nucleic Acids

DNA-Based Information Technologies

Lipids

Biological Membranes and Transport

Biosignaling

Bioenergetics and Biochemical Reaction Types

Glycolysis, Gluconeogenesis, and the Pentose Phosphate Pathway

Principles of Metabolic Regulation

The Citric Acid Cycle

Fatty Acid Catabolism

Amino Acid Oxidation and the Production of Urea

Oxidative Phosphorylation and Photophosphorylation

Carbohydrate Biosynthesis in Plants and Bacteria

Lipid Biosynthesis

Biosynthesis of Amino Acids, Nucleotides, and Related Molecules

Hormonal Regulation and Integration of Mammalian Metabolism

Genes and Chromosomes

DNA Metabolism

Protein Metabolism

Regulation of Gene Expression

Filters

Which statement is CORRECT with respect to $\rho$ (rho)-dependent termination of RNA synthesis?

Which statement about $\rho$ -independent termination of RNA transcription in E. coli is TRUE?