Lecture 11 – Bacterial transcription
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Questions and Answers

What is the primary role of transcription in gene expression?

  • To convert DNA sequences into RNA. (correct)
  • To modify proteins after translation.
  • To replicate DNA.
  • To translate RNA into proteins.

Which RNA molecule serves as the template for protein synthesis?

  • tRNA
  • mRNA (correct)
  • snRNA
  • rRNA

In bacterial transcription, which strand of DNA serves as the template strand?

  • `Coding strand
  • Sense strand
  • Antisense strand (correct)
  • Non-template strand

During transcription, which nucleotide replaces thymine in RNA?

Signup and view all the answers

What is the consequence of cytosine deamination in DNA?

<p>It becomes uracil, potentially leading to mutations. (A)</p> Signup and view all the answers

What is the function of the σ subunit in bacterial RNA polymerase?

<p>To facilitate the binding of RNA polymerase to promoter regions. (C)</p> Signup and view all the answers

What defines a polycistronic operon in bacterial transcription?

<p>Multiple genes transcribed as a single mRNA molecule. (B)</p> Signup and view all the answers

Which element of the bacterial promoter is typically recognized by RNA polymerase?

<p>Promoter regions (D)</p> Signup and view all the answers

In DNA footprinting, what does the “footprint” represent?

<p>The region of DNA that is protected from nuclease digestion. (B)</p> Signup and view all the answers

Which sequences are characteristic of a strong bacterial promoter?

<p>-10 and -35 sequences that closely match consensus sequences. (A)</p> Signup and view all the answers

What is the initial step in the transcription process?

<p>Elongation of the RNA strand. (B)</p> Signup and view all the answers

During the elongation phase of transcription, what happens to the RNA:DNA hybrid?

<p>It remains stable for a short length of the transcript. (C)</p> Signup and view all the answers

Which mechanism is involved in rho-independent transcription termination?

<p>Hairpin loop formation followed by poly-U stretch. (B)</p> Signup and view all the answers

What is the significance of the ω subunit in bacterial RNA polymerase?

<p>It enhances the stability and assembly of the enzyme. (B)</p> Signup and view all the answers

What distinguishes RNA polymerase from DNA polymerase?

<p>RNA polymerase synthesizes RNA without a primer. (B)</p> Signup and view all the answers

What is a common feature of bacterial transcription units?

<p>They may contain multiple genes organized in operons. (C)</p> Signup and view all the answers

Which of the following is true regarding the termination of transcription in bacteria?

<p>It always involves ribosome activity. (D)</p> Signup and view all the answers

What is the typical rate of RNA elongation by bacterial RNA polymerase?

<p>Approximately 50 nucleotides/sec (B)</p> Signup and view all the answers

Which of the following statements about σ factors is correct?

<p>Different σ factors recognize different promoter sequences. (B)</p> Signup and view all the answers

What triggers the transition from the closed promoter complex to the open promoter complex?

<p>Unwinding of the -10 region of DNA (C)</p> Signup and view all the answers

How does the presence of a hairpin structure in RNA contribute to transcription termination?

<p>It destabilizes the RNA polymerase-DNA complex. (B)</p> Signup and view all the answers

What is the role of topoisomerase during transcription?

<p>To relieve the supercoiling of DNA. (B)</p> Signup and view all the answers

Which of the following is true regarding the -35 and -10 consensus sequences?

<p>They are conserved elements that help RNA polymerase bind effectively. (B)</p> Signup and view all the answers

What is the primary function of ribosomal RNA (rRNA)?

<p>To form the structural and functional components of ribosomes. (C)</p> Signup and view all the answers

Which type of RNA is specifically involved in bringing amino acids to the ribosome during translation?

<p>tRNA (C)</p> Signup and view all the answers

What happens to the RNA polymerase once transcription is terminated?

<p>It dissociates from the DNA and newly synthesized RNA. (B)</p> Signup and view all the answers

What is the effect of having a strong promoter sequence in bacterial transcription?

<p>It increases the efficiency of RNA polymerase binding and transcription initiation. (B)</p> Signup and view all the answers

What is the typical structure of bacterial RNA polymerase?

<p>A multi-subunit complex. (B)</p> Signup and view all the answers

What is the significance of the +1 position in a bacterial promoter?

<p>It indicates the start of transcription. (A)</p> Signup and view all the answers

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