Eukaryotic Gene Transcription

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Questions and Answers

Which RNA polymerase synthesizes precursor of mature rRNA in eukaryotes?

RNA Pol I (correct)

RNA Pol IV

RNA Pol II

RNA Pol III

Which histone modification decreases histone interaction with DNA in eukaryotes?

Phosphorylation

Ubiquitination

Acetylation (correct)

Methylation

Which transcription factor recognizes and binds the TATA-box in eukaryotes?

TFIIH

TFIIF

TFIIB

TFIID (correct)

Which consensus sequence within 200 nt of the core promoter is considered a proximal regulatory element in eukaryotes?

CAAT box Signup and view all the answers

Which of the following is true about promoter regions in DNA?

Promoter regions affect the rate of transcription initiation. Signup and view all the answers

What is the function of enhancers in transcription initiation?

Enhancers affect the rate of transcription initiation. Signup and view all the answers

What is the difference between exons and introns in eukaryotic genes?

Exons are removed during splicing, while introns are transcribed into mRNA. Signup and view all the answers

Which enzyme is responsible for transcribing RNA in prokaryotes?

RNA polymerase I Signup and view all the answers

Which of the following is a major difference between prokaryotic and eukaryotic mRNAs?

Prokaryotic mRNAs have introns, while eukaryotic mRNAs do not. Signup and view all the answers

What is the role of transcription factors in eukaryotes?

Transcription factors regulate the rate of transcription. Signup and view all the answers

Which enzyme synthesizes tRNA, 5S rRNA, and some snRNA and snoRNA in eukaryotes?

RNA polymerase III Signup and view all the answers

What is the role of enhancers in eukaryotes?

Enhancer sequence bends or loops DNA for STF to interact with other TF bound to promoter and RNA pol II to stimulate transcription Signup and view all the answers

Which of the following is responsible for adding a 5'-cap to pre-mRNA in eukaryotes?

S-Adenosylmethionine Signup and view all the answers

What is the function of small nuclear ribonucleoprotein particles (snRNPs) in eukaryotic mRNA splicing?

snRNPs facilitate removal of introns by forming base pairs with consensus sequences at each end of the intron Signup and view all the answers

Which type of RNA is responsible for forming peptide bonds in protein synthesis?

rRNA Signup and view all the answers

What is the function of the sigma factor in prokaryotic transcription?

Recognizes the promoter region Signup and view all the answers

Which termination signal in prokaryotic transcription involves the formation of a GC-rich hairpin loop structure?

Rho-independent termination Signup and view all the answers

What is the role of the rho protein in rho-dependent termination in prokaryotic transcription?

Separates the RNA-DNA hybrid helix Signup and view all the answers

Which type of RNA is responsible for carrying the genetic information from DNA to the ribosomes in protein synthesis?

mRNA Signup and view all the answers

Which enzyme is responsible for transcribing DNA into RNA during prokaryotic transcription?

RNA polymerase Signup and view all the answers

What is the function of small interfering RNAs (siRNAs) in gene regulation?

Inhibit gene expression Signup and view all the answers

Which of the following is true about promoter-proximal elements and enhancers in transcription initiation?

Promoter-proximal elements and enhancers are specific sequences in DNA that determine where on the DNA template RNA polymerase binds to initiate transcription. Signup and view all the answers

What is the function of exons in eukaryotic genes?

Exons specify the coding region of proteins. Signup and view all the answers

What is the role of introns in eukaryotic genes?

Introns have no coding function. Signup and view all the answers

Which of the following is true about transfer RNA (tRNA)?

tRNA contains a single-strand of ribonucleotides Signup and view all the answers

Which of the following is true about messenger RNA (mRNA)?

mRNA carries genetic information from DNA to the site of protein synthesis Signup and view all the answers

Which of the following is true about prokaryotic gene transcription?

Only one strand of DNA serves as the template for transcription Signup and view all the answers

Which of the following is true about transcription termination in prokaryotes?

Rho-independent termination involves the formation of a GC-rich hairpin loop structure Signup and view all the answers

Which RNA polymerase is responsible for synthesizing nuclear precursors of mRNA in eukaryotes?

RNA Pol II Signup and view all the answers

Which histone modification promotes interaction between histone and DNA in eukaryotes?

Acetylation Signup and view all the answers

Which general transcription factor recruits RNA Pol II to the promoter in eukaryotes?

TFIIF Signup and view all the answers

Which consensus sequence located +1 of the transcription start site (TSS) in eukaryotes is known as the initiator?

Inr Signup and view all the answers

Which of the following is true about the posttranscriptional modifications of rRNA in eukaryotes?

rRNA is generated from a single pre-rRNA transcript Signup and view all the answers

Which of the following is true about the posttranscriptional modifications of tRNA in eukaryotes?

tRNA is generated from a long pre-tRNA transcript Signup and view all the answers

Which of the following is true about the posttranscriptional modifications of eukaryotic mRNA?

Pre-mRNA undergoes extensive modifications Signup and view all the answers

Which of the following is true about the addition of a 5'-cap to eukaryotic mRNA?

The 5'-cap stabilizes mRNA for initiation of translation Signup and view all the answers

Study Notes

RNA Polymerases in Eukaryotes

RNA Polymerase I synthesizes precursor of mature rRNA.
RNA Polymerase II transcribes nuclear precursors of mRNA.
RNA Polymerase III synthesizes tRNA, 5S rRNA, and some snRNA and snoRNA.

Histone Modifications

Acetylation of histones decreases their interaction with DNA, promoting transcriptional activation.
Methylation of histones can promote or inhibit DNA interactions depending on the context.

Transcription Factors and Promoter Elements

TATA-binding protein (TBP) recognizes and binds the TATA-box in eukaryotes.
Proximal regulatory elements are consensus sequences within 200 nucleotides of the core promoter, crucial for transcription regulation.

Enhancers and Promoter Regions

Enhancers are DNA elements that enhance transcription initiation by recruiting transcription factors.
Promoter regions are essential for initiating transcription; they primarily recruit RNA polymerase and transcription factors.

Exons vs. Introns

Exons are coding sequences within genes that are expressed in the final mRNA product.
Introns are non-coding sequences that are spliced out during mRNA processing.

RNA in Prokaryotes

RNA polymerase is the enzyme that synthesizes RNA from DNA in prokaryotes.
Transcription factors play critical roles in regulating gene expression by facilitating or inhibiting RNA polymerase binding.

mRNA Characteristics

Eukaryotic mRNAs undergo extensive post-transcriptional modifications, including capping, polyadenylation, and splicing.
Prokaryotic mRNAs are typically polycistronic and do not undergo such modifications.

Peptide Bond Formation and Genetic Information Transfer

Ribosomal RNA (rRNA) is responsible for forming peptide bonds during protein synthesis.
Messenger RNA (mRNA) carries genetic information from DNA to ribosomes for translation.

RNA Processing

Small nuclear ribonucleoprotein particles (snRNPs) facilitatespliceosome function during mRNA splicing.
Small interfering RNAs (siRNAs) play a role in gene regulation by targeting mRNA for degradation.

Rho-Dependent and Rho-Independent Termination

Rho protein is essential for rho-dependent transcription termination in prokaryotes, facilitating disengagement of RNA polymerase.
Rho-independent termination involves the formation of a GC-rich hairpin loop structure in the RNA.

Posttranscriptional Modifications

Eukaryotic rRNA undergoes modifications including methylation and pseudouridination during processing.
tRNA undergoes trimming and the addition of CCA at the 3' end, crucial for its function.

5'-Cap Addition

The addition of a 5'-cap to pre-mRNA enhances stability, facilitates nuclear export, and is critical for translation initiation.

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Description

Test your knowledge on eukaryotic gene transcription and the role of nuclear RNA pols. Explore the complexities of transcription in eukaryotes, including compartmentalization, different types of RNA pols for synthesizing rRNA, tRNA, and mRNA, the importance of transcription factors, and the unique promoter regions and chromatin involved in gene transcription.