Transcription is the process of creating an RNA copy of a gene sequence from DNA.
What is the significance of transcription in gene expression?
It is the first step in gene expression, transferring information from DNA to RNA.
What types of RNA are produced during transcription?
mRNA, tRNA, and rRNA.
What is the role of RNA polymerase in transcription?
RNA polymerase catalyzes the formation of RNA from the DNA template.
What is the function of the promoter in transcription?
The promoter is a DNA sequence where RNA polymerase binds to start transcription.
What is the terminator in the context of transcription?
The terminator is a sequence that signals the end of transcription.
What are the building blocks of RNA?
The building blocks of RNA are nucleotides: A, U, G, and C.
How does the DNA template strand differ from the coding strand?
The template strand is used for RNA synthesis, while the coding strand has the same sequence as the RNA (except for T being replaced by U).
How many types of RNA polymerase are present in prokaryotes?
There is only one type of RNA polymerase in prokaryotes.
What are the three types of RNA polymerase found in eukaryotes?
RNA polymerase I, II, and III.
What is the role of transcription factors in eukaryotic transcription?
Transcription factors help initiate and regulate transcription by binding to specific DNA sequences and interacting with RNA polymerase.
What is the significance of enhancers and silencers in eukaryotic transcription?
Enhancers increase transcription rates, while silencers decrease transcription rates.
How does transcription differ between prokaryotes and eukaryotes in terms of location?
In prokaryotes, transcription occurs in the cytoplasm, while in eukaryotes, it occurs in the nucleus.
What is the termination stage of transcription?
The termination stage occurs when RNA polymerase reaches a termination signal, releasing the newly synthesized RNA.
What happens during the elongation stage of transcription?
RNA polymerase moves along the template DNA strand, adding complementary RNA nucleotides to the growing RNA chain.
What occurs during the initiation stage of transcription?
RNA polymerase binds to the promoter region of the DNA and unwinds the DNA double helix.
What are the three main stages of transcription?
The three main stages are initiation, elongation, and termination.
What is a key difference in the complexity of initiation between prokaryotic and eukaryotic transcription?
Prokaryotic transcription initiation is simpler and requires fewer factors compared to eukaryotic transcription, which is more complex and requires many transcription factors.
What is the role of post-transcriptional modifications in eukaryotes?
Post-transcriptional modifications are essential for producing mature, functional RNA molecules.
What is 5' capping in post-transcriptional modifications?
5' capping is the addition of a 7-methylguanosine cap to the 5' end of the RNA, protecting it from degradation and aiding in ribosome binding.
What is splicing in the context of post-transcriptional modifications?
Splicing is the removal of introns and joining of exons in the RNA transcript.
What is 3' polyadenylation?
3' polyadenylation is the addition of a poly-A tail to the 3' end of the RNA, enhancing RNA stability and aiding in export from the nucleus.
What is RNA editing?
RNA editing is the alteration of the RNA sequence after transcription, which can change the amino acid sequence of the resulting protein.
Why are post-transcriptional modifications important for protein diversity?
They allow for alternative splicing, which can produce different protein isoforms from the same gene.
What is the relationship between transcription and DNA repair?
Transcription-coupled repair (TCR) is a specialized form of nucleotide excision repair that occurs when RNA polymerase II encounters DNA damage during transcription.
What proteins are involved in transcription-coupled repair (TCR)?
CSA and CSB proteins help recruit repair factors during TCR.
What happens when RNA polymerase II encounters DNA damage during transcription?
RNA polymerase II stalls at the site of DNA damage, triggering the recruitment of repair factors.
What is the significance of transcription-coupled repair (TCR)?
TCR prioritizes the repair of the template strand of actively transcribed genes.