RNA Synthesis and Processing

These flashcards cover key concepts related to RNA synthesis, its regulation, and processing in both prokaryotic and eukaryotic organisms, as detailed in the lecture notes.

What does RNA polymerase do during transcription?

It directs the synthesis of RNA using a DNA template.

Which nucleotides are found in RNA?

Nucleotides contain ribose, not deoxyribose.

What are promoters in transcription?

Specific DNA sequences in the 5′ region upstream of the initial transcription point.

What is the role of the σ subunit in transcription?

It is responsible for promoter recognition and initiation of transcription.

What happens at the transcription start site?

The DNA double helix is unwound to make the template strand accessible for RNA polymerase.

What are consensus sequences?

DNA sequences homologous in different genes of the same organism.

What is the function of the rho (ρ) factor in termination?

It is involved in rho-dependent termination, helping to terminate transcription.

How does transcription differ in eukaryotes compared to prokaryotes?

Transcription occurs within the nucleus in eukaryotes and requires mRNA processing before translation.

What three forms of RNA polymerase do eukaryotes possess?

RNA Pol I, RNA Pol II, RNA Pol III.

What is a TATA box?

A core-promoter element that binds the TATA-binding protein to determine the transcription start site.

What is the role of enhancers and silencers in gene transcription?

Enhancers increase transcription levels, while silencers decrease them.

What modifications are made to eukaryotic mRNAs after transcription?

Addition of a 5′ cap, addition of a 3′ tail, and excision of introns.

What are introns and exons?

Introns are regions not expressed in the final mRNA product, while exons are retained and expressed.

What is splicing?

The process of removing introns and joining exons in the formation of mature mRNA.

What is the spliceosome?

A complex that splices out introns from pre-mRNA and ligates exons together.