BIOL/MCBL 121 Introductory Microbiology Lecture 5 Quiz

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What is the function of RNA polymerase?

Generating RNA from a DNA template (correct)
Catalyzing the formation of ribosomes
Initiating translation of mRNA into protein
Synthesizing DNA from an RNA template

What is the role of sigma factor in RNA synthesis by RNA polymerase?

Stimulating elongation of RNA synthesis
Guiding the core enzyme to initiate transcription by recognizing promoters (correct)
Regulating the binding of nucleotides to the RNA strand
Assisting in termination of RNA synthesis

What is the general role of transcriptional regulators in gene expression?

Promoting the formation of open reading frames
Facilitating translation of mRNA into proteins
Sensing environmental/internal changes and altering gene expression (correct)
Directly synthesizing RNA from DNA templates

What distinguishes Rho-dependent transcriptional termination from Rho-independent transcriptional termination?

Requirement for a specific termination signal (C) Signup and view all the answers

In prokaryotic translation, what is the role of the Shine-Dalgarno sequence?

Initiating translation by recruiting ribosomes to the mRNA (D) Signup and view all the answers

What is the main function of open reading frames?

Coding for proteins or polypeptides (D) Signup and view all the answers

How do regulatory proteins contribute to gene expression?

By sensing and responding to cellular and environmental changes (D) Signup and view all the answers

What are the components of RNA polymerase?

Core enzyme and sigma factor (D) Signup and view all the answers

What is the main function of Pribnow Box in gene expression?

Recognizing promoters to guide RNA polymerase for transcription initiation (A) Signup and view all the answers

What distinguishes repressors from activators in gene regulation?

Repressors prevent transcription of target genes, while activators stimulate transcription of target genes (B) Signup and view all the answers

Which type of RNA regulates the stability or translation of specific mRNAs into proteins?

small RNAs (sRNA) (D) Signup and view all the answers

What is the function of a sigma factor in the initiation of transcription?

Binds DNA and recruits the core enzyme (D) Signup and view all the answers

What is the role of Rho in Rho-dependent termination during transcription?

Unwinds the RNA/DNA duplex and causes RNA polymerase to fall off of DNA (C) Signup and view all the answers

What is the function of tRNA in translation?

Binds individual amino acids and base pairs to codons in mRNA (C) Signup and view all the answers

What is the open reading frame (ORF) within mRNA?

A region between the transcriptional start and translational start (A) Signup and view all the answers

What is the role of ribosomal large (50s) subunit in translation?

Forms the catalytic center of the ribosome (B) Signup and view all the answers

What is the function of shine-dalgarno sequence on mRNA in prokaryotic translation?

Allows binding to 30s subunit of ribosome (C) Signup and view all the answers

What is the main difference between prokaryotic and eukaryotic translation?

Different ribosome structure (A) Signup and view all the answers

"Housekeeping" sigma factor is generally required for growth or maintenance of cellular functions. Which sigma factor can be seen as an alternative to "housekeeping" sigma factor?

Multiple σ factors in one cell to turn on the transcription of different sets of genes responding to different conditions: σ70 (B) Signup and view all the answers