Question 1

How does the concentration of ribonucleotide triphosphates play a role in the regulation of initiation?

Accepted Answer

Binding of the first nucleotide to RNA polymerase requires a higher concentration of ribonucleotide triphosphates compared to subsequent nucleotides. The half-saturation concentration for the first nucleotide is ~100μM while for subsequent nucleotides it is only ~10μM. This allows for efficient initiation and regulation of transcription by controlling the rate of binding of the first nucleotide.

Question 2

What type of enzyme activity is associated with the termination factor $\rho$?

Accepted Answer

The termination factor F1F1F1S1ρF1F1F10 is associated with helicase activity, which is crucial for unwinding the DNA double helix during replication and transcription processes.

Question 3

Rapid transcription of ribosomal RNA is thought to occur as a result of what unique feature in the DNA that encodes these genes?

Accepted Answer

E

Question 4

The E. coli core polymerase is missing the ____ subunit and binds to DNA with _______ specificity than the holoenzyme.

Accepted Answer

The E. coli core polymerase lacks the $\sigma$ subunit, which is responsible for promoter recognition, resulting in less specificity in binding to DNA compared to the holoenzyme that includes the $\sigma$ subunit.

Question 5

What is required for conversion from the closed-promoter complex to open-promoter complex?

Accepted Answer

The conversion from the closed-promoter complex to open-promoter complex requires DNA bending to expose the core promoter region, which leads to the recruitment of RNA polymerase and the formation of the open-promoter complex. ATP binding, ATP hydrolysis, GTP binding or GTP hydrolysis are not directly involved in this process.

Question 6

In eukaryotic cells, RNA polymerase ____ transcribes most of the ribosomal RNA, RNA polymerase ____ transcribes the major structural genes and RNA polymerase ____ transcribes tRNAs.

Accepted Answer

RNA polymerase I transcribes most of the ribosomal RNA (rRNA) including 18S, 5.8S, and 28S rRNA. 
RNA polymerase II transcribes the major structural genes including protein-coding genes, as well as miRNA genes and some non-coding RNA genes.
RNA polymerase III transcribes tRNA genes, 5S rRNA genes, and some small non-coding RNA genes.

Question 7

Rifampicin is known to inhibit RNA synthesis in E. coli. Once the first ten nucleotides have been incorporated, rifampicin does not inhibit RNA synthesis. Which of the following best explains how rifampicin functions?

Accepted Answer

Rifampicin can only bind to RNA polymerase when the polymerase is not bound to DNA. Once the polymerase has incorporated the first ten nucleotides, rifampicin no longer inhibits RNA synthesis.

Question 8

E. coli cells achieve a great deal of gene regulatory expression through the  $\sigma$subunit of RNA polymerase. Which  $\sigma$ subunit is present most often since it promotes the production of most of the proteins required under normal conditions within the cell?

Accepted Answer

The question seems to be incorrectly formatted with symbols and numbers that don't correspond to known subunits of RNA polymerase in E. coli. However, the correct answer choice is likely intended to refer to the sigma factor (σ) that is most commonly associated with the RNA polymerase in E. coli under normal conditions, which is σ^70 (sigma 70). This is the primary sigma factor used during exponential growth to recognize the promoters of genes required for most basic functions.

Question 9

What is the mechanism by which enhancers, despite the fact that they are often several kilobase pairs away from the promoter, activate transcription?

Accepted Answer

Enhancers can activate transcription by looping the DNA to bring distal enhancer elements in close proximity to the promoter region, allowing for the transcription factors and RNA polymerase to interact and initiate transcription. This looping mechanism enables the enhancer elements to have an effect on the transcriptional activity of the promoter, despite their distance.

Question 10

The concept of the operon was proposed based on the ability of E. coli to metabolize the disaccharide ________ only when present in large excess over glucose.

Accepted Answer

E. coli can metabolize lactose only when it is present in large excess over glucose. The discovery led to the proposal of the operon concept, which involves the coordinated control of gene expression in bacterial cells. The lactose operon is a classic example of an inducible operon in which the presence of lactose induces the expression of the genes involved in lactose metabolism.

Question 11

Which of the following is the first event in the post-translational processing of an E. coli tRNA?

Accepted Answer

Endonuclease cleavage of about 170 bases from the 3' end of the tRNA is the first event in the post-translational processing of an E. coli tRNA. This cleavage creates the proper 3'CCA end of the molecule which is essential for aminoacylation.

Question 12

Which subunit of E. coli RNA polymerase is responsible for DNA binding?

Accepted Answer

The answer of Which subunit of E. coli RNA polymerase...

Question 13

The E. coli promoter region contains a -10 consensus sequence of _________ on the sense strand.

Accepted Answer

The -10 consensus sequence of the E. coli promoter region on the sense strand is TATAAT, which is crucial for the binding of RNA polymerase to initiate transcription.

Question 14

Phosphorylation of the Rpb1 subunit of pol II causes what to occur?

Accepted Answer

Phosphorylation of the Rpb1 subunit of pol II causes dissociation from the promoter, allowing the transcription to proceed.

Question 15

During factor-independent termination, RNA polymerase pauses upon encountering a _____________ and is then displaced downstream upon encountering a ___________.

Accepted Answer

During factor-independent termination, RNA polymerase pauses upon encountering a G-C rich segment due to its stable structure and is then displaced downstream upon encountering a string of 4-8 A residues, as the RNA-DNA hybrid formed is weak and allows the polymerase to disengage.

Question 16

As RNA polymerase moves along the DNA, it creates a single stranded region of about 18 base pairs that is called a ________________.

Accepted Answer

The single stranded region created by RNA polymerase during transcription is called a transcription bubble. This bubble forms because RNA polymerase separates the DNA double helix into two strands, and then reads one of the strands as a template for RNA synthesis. The bubble is about 18 base pairs wide and moves along the DNA as transcription proceeds.

Question 17

In vivo, which of the following transcription initiation factors is required for binding to a TATA box?

Accepted Answer

TFIID is a transcription initiation factor that recognizes and binds to the TATA box within the promoter region of a gene. TFIIE, TFIIF, and TFIIH are also transcription initiation factors that function in the preinitiation complex, but they are not specifically required for binding to the TATA box. TAFs (TBP-associated factors) are proteins that interact with TFIID to regulate its activity, but they themselves do not directly bind to the TATA box.

Question 18

Transcription of the 5S rRNA gene occurs by ________ covering the entire gene so that pol III can ____________.

Accepted Answer

Transcription of the 5S rRNA gene occurs with TFIIIC covering the entire gene so that pol III can transcribe the gene several times before dissociating. This is different from other genes where TFIIB covers the gene and transcribes both strands of DNA before dissociating.

Question 19

Which of the following is the most common promoter element for pol II?

Accepted Answer

The TATA box (TATAAAA) is the most common promoter element for pol II, found in the majority of protein-coding genes. The other elements listed are also promoter elements but are less commonly found compared to the TATA box.

Question 20

Which subunit of E. coli RNA polymerase is responsible for the RNA polymerization reaction?

Accepted Answer

The β subunit of E. coli RNA polymerase is responsible for the RNA polymerization reaction.

Quiz 27: Information Readout: Transcription and Post-Transcriptional Processing

How does the concentration of ribonucleotide triphosphates play a role in the regulation of initiation?

What type of enzyme activity is associated with the termination factor $\rho$ ?

Rapid transcription of ribosomal RNA is thought to occur as a result of what unique feature in the DNA that encodes these genes?

The E. coli core polymerase is missing the subunit and binds to DNA with ___ specificity than the holoenzyme.

What is required for conversion from the closed-promoter complex to open-promoter complex?

In eukaryotic cells, RNA polymerase transcribes most of the ribosomal RNA, RNA polymerase transcribes the major structural genes and RNA polymerase transcribes tRNAs.

Rifampicin is known to inhibit RNA synthesis in E. coli. Once the first ten nucleotides have been incorporated, rifampicin does not inhibit RNA synthesis. Which of the following best explains how rifampicin functions?

E. coli cells achieve a great deal of gene regulatory expression through the $\sigma$ subunit of RNA polymerase. Which $\sigma$ subunit is present most often since it promotes the production of most of the proteins required under normal conditions within the cell?

What is the mechanism by which enhancers, despite the fact that they are often several kilobase pairs away from the promoter, activate transcription?

The concept of the operon was proposed based on the ability of E. coli to metabolize the disaccharide ________ only when present in large excess over glucose.

Which of the following is the first event in the post-translational processing of an E. coli tRNA?

Which subunit of E. coli RNA polymerase is responsible for DNA binding?

The E. coli promoter region contains a -10 consensus sequence of _________ on the sense strand.

Phosphorylation of the Rpb1 subunit of pol II causes what to occur?

During factor-independent termination, RNA polymerase pauses upon encountering a ___ and is then displaced downstream upon encountering a _.

As RNA polymerase moves along the DNA, it creates a single stranded region of about 18 base pairs that is called a ________________.

In vivo, which of the following transcription initiation factors is required for binding to a TATA box?

Transcription of the 5S rRNA gene occurs by covering the entire gene so that pol III can ____.

Which of the following is the most common promoter element for pol II?

Which subunit of E. coli RNA polymerase is responsible for the RNA polymerization reaction?

Quiz 27: Information Readout: Transcription and Post-Transcriptional Processing

How does the concentration of ribonucleotide triphosphates play a role in the regulation of initiation?

What type of enzyme activity is associated with the termination factor ρ\rhoρ ?

Rapid transcription of ribosomal RNA is thought to occur as a result of what unique feature in the DNA that encodes these genes?

The E. coli core polymerase is missing the ____ subunit and binds to DNA with _______ specificity than the holoenzyme.

What is required for conversion from the closed-promoter complex to open-promoter complex?

In eukaryotic cells, RNA polymerase ____ transcribes most of the ribosomal RNA, RNA polymerase ____ transcribes the major structural genes and RNA polymerase ____ transcribes tRNAs.

Rifampicin is known to inhibit RNA synthesis in E. coli. Once the first ten nucleotides have been incorporated, rifampicin does not inhibit RNA synthesis. Which of the following best explains how rifampicin functions?

E. coli cells achieve a great deal of gene regulatory expression through the σ\sigmaσ subunit of RNA polymerase. Which σ\sigmaσ subunit is present most often since it promotes the production of most of the proteins required under normal conditions within the cell?

What is the mechanism by which enhancers, despite the fact that they are often several kilobase pairs away from the promoter, activate transcription?

The concept of the operon was proposed based on the ability of E. coli to metabolize the disaccharide ________ only when present in large excess over glucose.

Which of the following is the first event in the post-translational processing of an E. coli tRNA?

Which subunit of E. coli RNA polymerase is responsible for DNA binding?

The E. coli promoter region contains a -10 consensus sequence of _________ on the sense strand.

Phosphorylation of the Rpb1 subunit of pol II causes what to occur?

During factor-independent termination, RNA polymerase pauses upon encountering a _____________ and is then displaced downstream upon encountering a ___________.

As RNA polymerase moves along the DNA, it creates a single stranded region of about 18 base pairs that is called a ________________.

In vivo, which of the following transcription initiation factors is required for binding to a TATA box?

Transcription of the 5S rRNA gene occurs by ________ covering the entire gene so that pol III can ____________.

Which of the following is the most common promoter element for pol II?

Which subunit of E. coli RNA polymerase is responsible for the RNA polymerization reaction?

What type of enzyme activity is associated with the termination factor $\rho$ ?

The E. coli core polymerase is missing the subunit and binds to DNA with ___ specificity than the holoenzyme.

In eukaryotic cells, RNA polymerase transcribes most of the ribosomal RNA, RNA polymerase transcribes the major structural genes and RNA polymerase transcribes tRNAs.

E. coli cells achieve a great deal of gene regulatory expression through the $\sigma$ subunit of RNA polymerase. Which $\sigma$ subunit is present most often since it promotes the production of most of the proteins required under normal conditions within the cell?

During factor-independent termination, RNA polymerase pauses upon encountering a ___ and is then displaced downstream upon encountering a _.

Transcription of the 5S rRNA gene occurs by covering the entire gene so that pol III can ____.