Transcription - Genetics

rRNA

Ribosomal RNA, a structural component of the ribosome, accounting for less than 5% of cellular RNAs.

mRNA

Messenger RNA, which carries genetic information from DNA to the ribosome for protein synthesis.

tRNA

Transfer RNA, which translates the genetic code from mRNA into amino acid sequences during translation.

DNA Coding Strand

The strand of DNA that has the same sequence as mRNA, except with thymine instead of uracil.

Prokaryotic Promoter

Located upstream of the gene, recognized by RNA polymerase and sigma factors.

Eukaryotic Promoter

The region where RNA polymerase binds to transcribe the gene into mRNA, involving transcription factors.

Alternative Splicing

A process in eukaryotes where a single gene can produce multiple protein variants by splicing out different combinations of exons.

Operons

Clusters of genes in prokaryotes that are transcribed together into a single mRNA molecule, allowing for coordinated regulation.

Pre-mRNA

The initial form of mRNA that contains both exons and introns.

Mature mRNA

The final form of mRNA that contains only exons, with introns spliced out, including a 5' cap and poly-A tail.

Exons

Coding regions in mRNA that remain after splicing and are translated into protein.

Introns

Non-coding regions in pre-mRNA that are removed during splicing, potentially having regulatory functions.

5' UTR

Untranslated region that regulates translation initiation and may affect mRNA stability and localization.

3' UTR

Untranslated region involved in mRNA stability, localization, and translation efficiency.

5' Cap

A structure that protects mRNA from degradation and is required for translation initiation.

Poly-A tail

A sequence that stabilizes mRNA and promotes its export from the nucleus.

Splicing

The process of removing introns from pre-mRNA and joining exons to form mature mRNA.

Transcription

The synthesis of RNA from a DNA template, catalyzed by RNA polymerase.

Translation

The synthesis of proteins from mRNA at the ribosome.

Rho-dependent termination

A mechanism where the Rho protein catches up with RNA polymerase to stop transcription.

Rho-independent termination

A mechanism where the RNA forms a hairpin loop causing RNA polymerase to dissociate.

RNA polymerase II

The enzyme in eukaryotes responsible for synthesizing mRNA.

TATA box

A promoter region recognized by TATA-binding protein to initiate transcription.

Polysomes

Clusters of ribosomes that translate a single mRNA molecule; found in both prokaryotes and eukaryotes.

Genomic information flow

The concept that genetic information flows from DNA to RNA and then to protein.

Sigma factors

Proteins that bind to promoters in prokaryotes to recruit RNA polymerase.

Transcription factors

Proteins that help initiate transcription by binding to the promoter in eukaryotes.

Operon function

Allows efficient regulation of genes working together in metabolic pathways.

Retroviruses

Viral exceptions to the flow of information, reversing transcribing RNA into DNA using reverse transcriptase.

Bacterial RNA polymerase structure

Composed of a core enzyme and a sigma factor directing it to the promoter.

Differences between RNA and DNA polymerases

RNA polymerase synthesizes RNA without needing a primer while DNA polymerase requires one.

Transcription initiation differences

Eukaryotic transcription involves transcription factors and a TATA box; prokaryotic uses sigma factors.