RNA Synthesis

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Questions and Answers

Which type of RNA is involved in regulating mRNA expression?

mRNA

small RNA (correct)

tRNA

rRNA

What is the function of RNA polymerase enzymes in prokaryotes?

Synthesize rRNA

Synthesize mRNA (correct)

Regulate mRNA expression

Synthesize tRNA

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

Presence of poly(A) tail

Presence of exons

Presence of introns (correct)

Presence of 5' cap

What is the role of transcription factors in eukaryotes?

Regulate mRNA expression Signup and view all the answers

What is the effect of enzymes on chromatin structure in eukaryotes?

Promote gene expression Signup and view all the answers

What are the major steps in eukaryotic transcription of an RNA molecule?

Promoter recognition, DNA unwinding, RNA synthesis Signup and view all the answers

Which type of RNA polymerase is responsible for synthesizing the precursor of mature rRNA in eukaryotes?

RNA Pol I Signup and view all the answers

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

RNA Pol II Signup and view all the answers

Which of the following is NOT a core promoter element for RNA Pol II in eukaryotes?

CAAT box Signup and view all the answers

Which of the following is NOT a function of general transcription factors (GTFs) in eukaryotes?

Initiate transcription Signup and view all the answers

Which type of regulatory element is located within 200 nt of the core promoter in eukaryotes?

Proximal regulatory element Signup and view all the answers

Which of the following is NOT a binding domain of specific transcription factors (STFs) in eukaryotes?

RNA-binding domain Signup and view all the answers

Which DNA sequences determine where on the DNA template RNA polymerase binds to initiate transcription?

Promoter regions Signup and view all the answers

What is the function of promoter-proximal elements and enhancers in transcription initiation?

They affect the rate of transcription initiation Signup and view all the answers

What is the function of exons in eukaryotic genes?

They specify the coding region of proteins Signup and view all the answers

What is the function of introns in eukaryotic genes?

They have no coding function Signup and view all the answers

What is the process called that removes introns from the primary transcript of eukaryotic genes?

Splicing Signup and view all the answers

What is the final product of the modification of the primary transcript of eukaryotic genes?

Mature mRNA Signup and view all the answers

Which enzyme is responsible for transcribing genes into a single-stranded RNA?

RNA polymerase Signup and view all the answers

What is the function of the 5'-cap in eukaryotic mRNA?

Stabilizes mRNA for initiation of translation Signup and view all the answers

Which RNA polymerase is responsible for synthesizing tRNA, 5S rRNA, and some snRNA and snoRNA?

RNA polymerase III Signup and view all the answers

What is the role of small nuclear RNA (snRNA) in mRNA splicing?

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

What is the purpose of posttranscriptional modifications of RNA?

To add unique identities to different RNA species Signup and view all the answers

Which of the following is true about eukaryotic mRNA splicing?

The number of introns varies among different mRNA transcripts Signup and view all the answers

Which of the following types of RNA is responsible for forming peptide bonds during protein synthesis?

rRNA Signup and view all the answers

Which of the following is NOT a characteristic of mRNA in eukaryotes?

Has a monocistronic structure Signup and view all the answers

Which of the following is NOT a phase of transcription in E. coli?

Translation Signup and view all the answers

Which of the following is NOT a component of the prokaryotic RNA polymerase holoenzyme?

Omega (Ω) Signup and view all the answers

Which of the following sequences is NOT part of the promoter region in prokaryotic transcription?

-10 sequence: 5'-TATAAT-3' Signup and view all the answers

Which of the following termination mechanisms in prokaryotic transcription requires a protein?

Rho-dependent termination Signup and view all the answers

Study Notes

RNA and Transcription

MicroRNA (miRNA) is involved in regulating mRNA expression
RNA polymerase enzymes in prokaryotes synthesize RNA molecules from DNA templates

Prokaryotic vs. Eukaryotic mRNA

A major difference between prokaryotic and eukaryotic mRNAs is that eukaryotic mRNAs have a more complex structure, with introns and exons, and undergo post-transcriptional modifications

Transcription Factors in Eukaryotes

Transcription factors in eukaryotes bind to specific DNA sequences to regulate gene expression
They recruit RNA polymerase and other transcription machinery to initiate transcription

Chromatin Structure in Eukaryotes

Enzymes can modify chromatin structure in eukaryotes to make genes accessible or inaccessible for transcription

Eukaryotic Transcription

The major steps in eukaryotic transcription of an RNA molecule are: initiation, elongation, and termination
RNA polymerase I is responsible for synthesizing the precursor of mature rRNA in eukaryotes
RNA polymerase II is responsible for synthesizing the nuclear precursors of mRNA in eukaryotes

Core Promoter Elements

The TATA box is a core promoter element for RNA Pol II in eukaryotes

Regulatory Elements in Eukaryotes

Proximal promoter elements are located within 200 nt of the core promoter in eukaryotes
Enhancers are distant regulatory elements that can loop back to the promoter to activate transcription

Transcription Initiation

The promoter sequence determines where RNA polymerase binds to initiate transcription
Promoter-proximal elements and enhancers function in transcription initiation

Eukaryotic Genes

Exons are coding regions in eukaryotic genes that are expressed in the final mRNA
Introns are non-coding regions in eukaryotic genes that are removed during RNA splicing
Splicing removes introns from the primary transcript of eukaryotic genes
The final product of the modification of the primary transcript of eukaryotic genes is a mature mRNA

RNA Polymerase

RNA polymerase is the enzyme responsible for transcribing genes into a single-stranded RNA

mRNA Modifications

The 5'-cap in eukaryotic mRNA is a modified nucleotide that protects the mRNA from degradation
RNA polymerase III is responsible for synthesizing tRNA, 5S rRNA, and some snRNA and snoRNA

mRNA Splicing

Small nuclear RNA (snRNA) plays a role in mRNA splicing
Posttranscriptional modifications of RNA occur after transcription and include splicing, capping, and polyadenylation

Protein Synthesis

tRNA is responsible for forming peptide bonds during protein synthesis

mRNA Characteristics

Eukaryotic mRNA is typically monocistronic, meaning it codes for a single protein

Prokaryotic Transcription

The phases of transcription in E. coli are: initiation, elongation, and termination
The sigma factor is a component of the prokaryotic RNA polymerase holoenzyme
The Pribnow box is a sequence part of the promoter region in prokaryotic transcription
The rho-dependent mechanism is a termination mechanism in prokaryotic transcription that requires a protein

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Description

Test your knowledge on nuclear RNA polymerases in eukaryotic gene transcription! Learn about the complex process, compartmentalization, different RNA polymerases for different types of RNA synthesis, transcription factors, promoter regions, and more.