RNA Transcription

Flashcards about RNA Transcription.

What is RNA transcription?

The conversion of a part of the DNA into RNA molecules, preformed by RNA polymerases.

What are RNA polymerases?

Enzymes that create phosphodiester bridges between RNA nucleotides, elongating the RNA strand from its 5' to its 3' end.

What is the sense (coding) strand?

The DNA strand not involved in the transcription process.

What is the antisense (noncoding) strand?

The DNA strand serving as the template for RNA polymerase.

What are promoter sites?

Specific sequences on the DNA strands that are recognized by the RNA polymerase complex as the beginning point for translation.

What is the rho (ρ) factor?

A helicase that unwinds DNA:RNA hybrids and dissociates the complex during transcription termination.

What dictates intrinsic termination in transcription?

Specific sites in the DNA strand containing GC rich elements that lead to spontaneous formation of stem-loop structures, terminating transcription.

What overcomes Nucleosome gene expression repression?

Enzymes that covalently modify histone proteins and alter their interaction with DNA and Chromatin remodeling complexes.

What does RNA polymerase I synthesize?

Synthesizes ribosomal RNA.

What does RNA polymerase II synthesize?

Synthesizes most non-coding RNA genes and all mRNA.

What does RNA polymerase III synthesize?

Synthesizes tRNA, some ribosomal RNA, and smaller RNA molecules.

What are core promoters?

50-100 bp region within which the transcription start site (TSS) lies; locations where RNA polymerase complex is assembled.

What possesses a GGGCCG or GC box promoter sequence?

Housekeeping genes found in all tissues.

What are enhancers and silencers as regulatory elements?

More distantly located on the DNA strand and recognized by specific DNA-binding proteins.

What is capping in post-transcription modifications?

Addition of modified G-base at 5' end.

What protects RNA transcripts from degradation in the cytosol?

Addition of poly A-tail at 3' end.

What are exons?

Coding regions.

What are introns?

Non-coding regions.

What is the splicing process?

Removal of intron segments from RNA transcript and ligating the neighboring exons back together.

What is RNA editing?

Deamination of bases in transcripts A to I (inosine) or C to U.