RNA Types and Transcription Processes

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Questions and Answers

Which RNA type is primarily responsible for carrying genetic information?

tRNA

rRNA

mRNA (correct)

snRNA

What is the role of rho protein during prokaryotic transcription termination?

To form the GC hairpin loop

To synthesize rRNA during elongation

To initiate RNA synthesis at the promoter

To bind to the rut site and cause termination (correct)

What triggers the initiation of eukaryotic transcription?

Binding of RNA polymerase II directly to the gene

The presence of exons in the mRNA

Splicing of hnRNA

Transcription factors binding to the TATA box (correct)

During the elongation phase of transcription, what is primarily synthesized?

hnRNA Signup and view all the answers

Which of the following describes the process of splicing?

Joining exons together while removing introns Signup and view all the answers

Which RNA polymerase is responsible for synthesizing mRNA in eukaryotic cells?

RNA Polymerase II Signup and view all the answers

What is the function of the 5' cap added during hnRNA processing?

To protect the RNA from degradation and aid in recognition by ribosomes Signup and view all the answers

What sequence signals the end of transcription in eukaryotes?

AAUAAA polyadenylation signal Signup and view all the answers

In prokaryotic transcription, what occurs at the Pribnow box?

Binding of RNA polymerase holoenzyme Signup and view all the answers

Which of the following sequences is typically associated with Rho-dependent termination in prokaryotic transcription?

rut site Signup and view all the answers

What is the primary function of snRNA in the context of eukaryotic transcription?

Catalyze splicing Signup and view all the answers

What occurs during the elongation phase of prokaryotic transcription?

Synthesis of RNA from rNTPs Signup and view all the answers

After hnRNA undergoes splicing, what is the final product?

Mature mRNA Signup and view all the answers

Which of the following best describes the role of RNA polymerase I in eukaryotic cells?

Synthesizes rRNA Signup and view all the answers

Which RNA type is involved in translating the genetic code into amino acids during protein synthesis?

tRNA Signup and view all the answers

What mechanism is primarily responsible for the cleavage of RNA downstream of the polyadenylation signal in eukaryotic transcription termination?

Endonucleolytic cleavage Signup and view all the answers

In eukaryotic transcription initiation, which complex binds to the TATA box?

TFIID with TBP Signup and view all the answers

What structural formation occurs during eukaryotic splicing as introns are removed?

Lariat structure Signup and view all the answers

What is the primary product formed during the elongation phase of eukaryotic transcription?

hnRNA Signup and view all the answers

Which RNA polymerase in eukaryotes is responsible for the synthesis of tRNA?

RNA Polymerase III Signup and view all the answers

What structural feature is formed during splicing when introns are removed?

Lariat structure Signup and view all the answers

In prokaryotic transcription, what is the role of the sigma factor in the initiation process?

It assists RNA polymerase in binding to the promoter. Signup and view all the answers

What is the primary function of the poly-A tail added during hnRNA processing?

To provide stability and facilitate export from the nucleus. Signup and view all the answers

Which of the following statements regarding eukaryotic transcription factors is true?

They assist in the binding of RNA polymerase to the promoter region. Signup and view all the answers

Which process occurs during rho-dependent termination in prokaryotic transcription?

Binding of the Rho protein to the rut site. Signup and view all the answers

What is the primary role of snRNPs in eukaryotic transcription?

To catalyze the splicing of pre-mRNA. Signup and view all the answers

What function does rRNA serve within a cell?

Forms the structural and functional components of ribosomes Signup and view all the answers

Which of the following correctly describes the termination process during prokaryotic transcription?

Termination can occur through both Rho-independent and Rho-dependent mechanisms Signup and view all the answers

What is the primary role of the polyadenylation signal in eukaryotic transcription?

To ensure proper termination of transcription Signup and view all the answers

During splicing of hnRNA, what occurs after the formation of a lariat structure?

Introns are excised and exons are joined together Signup and view all the answers

Which factor is primarily responsible for recruiting RNA polymerase II during eukaryotic transcription initiation?

TFIID with TBP Signup and view all the answers

What role does the 5' cap play in the processing of hnRNA?

Stabilizes the mRNA and assists in ribosome recognition Signup and view all the answers

In eukaryotic cells, which RNA polymerase is responsible for synthesizing rRNA?

RNA Polymerase I Signup and view all the answers

What is a distinguishing feature of Rho-independent transcription termination in prokaryotes?

Involves a GC-rich hairpin loop followed by a U-rich sequence Signup and view all the answers

What is the significance of hnRNA (pre-mRNA) in eukaryotic cells?

It contains both introns and exons before processing into mature mRNA Signup and view all the answers

Study Notes

RNA Types

mRNA: Carries genetic information
tRNA: Transfers amino acids during translation
rRNA: Forms ribosomes
snRNA: Involved in splicing

Prokaryotic Transcription

Initiation: RNA polymerase holoenzyme (core enzyme + sigma factor) binds the Pribnow box in the promoter region.
Elongation: Core RNA polymerase synthesizes RNA by adding rNMPs.
Termination:
- Rho-Independent: GC hairpin loop and U-rich sequence cause detachment of RNA polymerase.
- Rho-Dependent: Rho protein binds to the rut site, stopping transcription.

Eukaryotic Transcription

Initiation: Transcription factors like TFIID with TBP bind promoter elements (TATA box), recruiting RNA Polymerase II.
Elongation: Produces hnRNA (pre-mRNA) that includes introns.
Termination: Polyadenylation signal (AAUAAA) sequence signals the end of transcription; cleavage occurs downstream.

RNA Polymerases in Eukaryotes

Polymerase I: Synthesizes rRNA
Polymerase II: Synthesizes mRNA
Polymerase III: Synthesizes tRNA and 5S rRNA

hnRNA Processing to Form Mature mRNA

Capping: 5' cap added for stability and ribosome recognition.
Polyadenylation: Poly-A tail added to 3' end for stability.
Splicing: Introns are removed, and exons are joined by snRNPs, forming a lariat structure.

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Description

This quiz covers the various types of RNA and their functions, as well as the detailed processes of prokaryotic and eukaryotic transcription. You will learn about the roles of mRNA, tRNA, rRNA, and how transcription is initiated, elongated, and terminated in both cell types.