Molecular Biology RNA Transcription Quiz

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Questions and Answers

Which RNA Polymerase is responsible for transcribing mRNA and microRNA?

RNA Pol III

RNA Pol II (correct)

RNA Pol IV

RNA Pol I

What is the primary function of the TATA Binding Protein (TBP)?

To bind the TATA box and recruit transcription factors (correct)

To add a methyl group to RNA

To phosphorylate RNA Polymerase II

To unwind DNA during transcription

Which process involves the addition of a guanosine monophosphate to the RNA strand?

Promoter Recognition

Splicing

5’ Capping (correct)

Polyadenylation

Which factor plays a role in both helicase and kinase activities during transcription initiation?

TFIIH Signup and view all the answers

What role do Poly-A binding proteins serve during RNA processing?

They protect the RNA from degradation. Signup and view all the answers

During transcription elongation, what is the importance of CTD phosphorylation?

It provides binding sites for processing enzymes. Signup and view all the answers

What does the Cleavage and Polyadenylation Specificity Factor bind to during RNA processing?

AAUAAA sequence Signup and view all the answers

Which RNA Polymerase is involved in ribosome synthesis by transcribing rRNA genes?

RNA Pol I Signup and view all the answers

What role does telomerase play in the elongation process of telomeres?

It extends the telomeres by adding DNA sequences to the 3' overhang. Signup and view all the answers

Which process occurs in eukaryotic cells but not in prokaryotic cells?

RNA processing with 5’ capping and polyadenylation Signup and view all the answers

Which type of RNA is involved in regulating mRNA stability and translation?

miRNA Signup and view all the answers

What feature distinguishes RNA from DNA regarding its stability?

RNA is less stable because it is single-stranded. Signup and view all the answers

What is the function of telomere binding proteins like TRF1 and TRF2?

To stabilize telomeres and protect chromosome ends. Signup and view all the answers

Which of the following is true about the 3' overhang of telomeres?

It is protected by the T-loop structure formed by telomerase. Signup and view all the answers

What process is described by the elongation phase in the context of telomere maintenance?

The extension of telomeres by adding repeats to the 3' end of DNA. Signup and view all the answers

What does the start codon AUG signify in the context of protein synthesis?

The first amino acid in a protein sequence Signup and view all the answers

Which type of RNA is most abundant and plays a structural role in ribosomes?

rRNA Signup and view all the answers

What is the primary role of the 5' splice donor sequence in intron splicing?

To provide a recognition site for the spliceosome components. Signup and view all the answers

Which component is responsible for phosphorylating RNA polymerase II during the initiation stage of transcription?

TFIIH Signup and view all the answers

What role does the guanosine cofactor play in the self-splicing of introns?

It provides reactive hydroxyl groups for transesterification. Signup and view all the answers

In what stage of transcription does the RNA polymerase II pause to enable a quick stress response?

Pausing Signup and view all the answers

Which type of alternative splicing is most commonly observed?

Exon skipping. Signup and view all the answers

How does miRNA function differently from siRNA in gene regulation?

miRNA inhibits translation rather than degrading mRNA. Signup and view all the answers

What is the outcome of the second step in the two-step transesterification splicing mechanism?

Exon 1 and exon 2 are joined together. Signup and view all the answers

Which element facilitates the processing of RNA through co-transcriptional modifications?

RNA polymerase II phosphorylated CTD Signup and view all the answers

What is the primary mechanism by which Dicer processes hairpin RNA into miRNA?

It cleaves the hairpin structure into fragments. Signup and view all the answers

How do introns contribute to gene regulation?

By folding into double-stranded RNA that can silence genes. Signup and view all the answers

Which enzyme's primary function is to remove the poly-A tail from mRNA during decay?

Deadenylase. Signup and view all the answers

What is the first step in the siRNA pathway after Dicer processes dsRNA?

Single-stranded RNA is created by helicase. Signup and view all the answers

Which exonuclease is involved in the torpedo model of transcription termination?

Xrn2 Signup and view all the answers

Which of the following is NOT a component of the spliceosome assembly?

Xrn2 exonuclease Signup and view all the answers

Which mechanism interferes with translation initiation by blocking ribosome assembly at the 5' end?

Cap Binding Block. Signup and view all the answers

Which of the following distinguishing features characterizes siRNA in relation to miRNA?

Has perfect complementarity with its target. Signup and view all the answers

What is the role of Inosine in the wobble hypothesis?

It can pair with Adenine, Cytosine, or Uracil. Signup and view all the answers

Which of the following statements is true concerning prokaryotic ribosomes?

The small subunit is composed of 16S rRNA and 21 proteins. Signup and view all the answers

During the initiation of translation in eukaryotes, what is the function of the Cap Binding Complex?

It binds to the mRNA cap and helps locate the first AUG codon. Signup and view all the answers

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

It positions the AUG codon in the P site of the ribosome. Signup and view all the answers

Which ribosomal site is primarily responsible for holding the growing polypeptide chain during translation?

P site Signup and view all the answers

What catalytic activity does the peptidyl transferase perform?

It catalyzes the formation of peptide bonds. Signup and view all the answers

Which RNA polymerase is responsible for synthesizing 5S rRNA?

RNA polymerase III Signup and view all the answers

What happens to deacylated tRNA after it leaves the P site?

It is released from the E site. Signup and view all the answers

What is the first step in producing cDNA from eukaryotic mRNA?

Extract mRNA from eukaryotic cells. Signup and view all the answers

Which enzyme is used to create sticky ends by digesting the cDNA?

EcoRI Signup and view all the answers

During the process of producing recombinant DNA, what method is used for delivering Fosmids into bacterial cells?

Transduction Signup and view all the answers

Which technique is specifically used to confirm the presence of a DNA insert in a plasmid?

Agarose gel electrophoresis after digestion Signup and view all the answers

What role does T5 exonuclease play in the Gibson Assembly method?

Chews back DNA ends to create overlaps. Signup and view all the answers

What is a characteristic feature of dideoxynucleotide triphosphates (ddNTPs)?

Lacks a hydroxyl group at the 3' position. Signup and view all the answers

What is the purpose of the His-tag in protein purification?

To allow binding to Ni2+ beads. Signup and view all the answers

Which method allows the cloning of multiple DNA fragments in one reaction without using restriction enzymes?

Gibson Assembly Signup and view all the answers

Study Notes

Key Experiments Leading to DNA as Genetic Material

Frederick Griffith (1928): Transformation in Streptococcus pneumoniae bacteria
Avery, MacLeod, and McCarty (1944): DNA was the transforming agent
Hershey and Chase (1952): DNA entered E. coli cells; 32P labels DNA, 35S labels protein

Experimental Evidence for Semiconservative Replication

Meselson and Stahl (1958) used cesium chloride centrifugation and different nitrogen isotopes (N15 and N14) to label DNA
First generation: Intermediate density (one heavy strand, one light strand)
Second generation: A mix of light and intermediate density

Semiconservative DNA Replication - Arthur Kornberg

Kornberg used the wrong polymerase (DNA pol I), which was too slow and short.
DNA Polymerases in E. coli:
- DNA polymerase I (Pol I): Major repair enzyme, 3' to 5' and 5' to 3' exonucleases
- DNA polymerase II (Pol II): Replication restarts after damage
- DNA polymerase III (Pol III): Main replication enzyme, synthesizes long DNA strands, 3' to 5' exonuclease activity
- DNA polymerase IV and V: Error-prone repair mechanisms

Replicating the Bacterial Chromosome

John Cairns used 3H-thymidine incorporation to study DNA synthesis
One round of replication: chromosome is a double-stranded circular DNA molecule
Second round of replication: DNA polymerase synthesizes DNA in two directions simultaneously

Steps in DNA Replication (Lagging Strand)

Primase synthesizes RNA primer (5' to 3')
DNA polymerase III elongates leading strand continuously
DNA synthesized in Okazaki fragments, starting with RNA primers
DNA polymerase I cleaves RNA primers, fills gaps and synthesizes DNA (5' to 3')
DNA ligase seals gaps between Okazaki fragments

Replication Bubble in Prokaryotes (E. coli)

OriC: Origin of replication in E. coli (circular genome)
Replication in both directions from origin, forming two replication forks
Primosome: primase and helicase
Replisome: Multi-protein complex that carries out DNA synthesis

DNA Replication in Eukaryotes

Multiple Origins of Replication
S Phase
DNA wrapped around histones and needs to be unwound
Telomerase
- Telomeres: protective repeated DNA sequences at ends of chromosomes
- RNA of telomerase: template for extending 3' overhang of telomeres
- T-loop: 3' overhang of telomeres, stabilizing chromosomes

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Description

Test your knowledge on the intricacies of RNA transcription and processing with this quiz! Delve into topics such as RNA polymerases, transcription factors, and the roles of various proteins during RNA maturation. Perfect for students studying molecular biology and genetics.