Gene Expression: Transcription

These flashcards cover key vocabulary related to gene expression and the processes of transcription and RNA processing.

Gene Expression

The process by which DNA directs the synthesis of proteins or RNA.

Transcription Unit

The stretch of DNA that is transcribed into RNA

Downstream

The direction transcription is moving

Upstream

The opposite direction transcription is moving

Transcription

The synthesis of RNA using a DNA template.

RNA Polymerase

Enzyme that links ribonucleotides to form an RNA chain during transcription.

Transcription Factors

Eukaryotic proteins that bind to DNA before RNA polymerase

Transcription initiation complex

A complex formed between RNA polymerase and the transcription factors

Initiation: Start point

The site where transcription actually begins

Initiation: TATA box

The specific sequence in eukaryotic promoters- TATAAAA- to which transcription factors bind to establish the transcription initiation complex

Termination Bacteria: Terminator Sequence

The sequence on DNA which tells RNA polymerase to stop and is then transcribed into RNA forming a loop causing RNA polymerase to fall off

Termination eukaryotes: Polyadenylation signal

Created when RNA polymerase passes through a specific sequence of DNA (AAUAAA) creating this signal that allow proteins associated to cut mRNA free from RNA polymerase

Pre- mRNA/primary transcript

RNA that must be modified before it leaves the nucleus as mature mRNA

Central Dogma

The flow of genetic information from DNA to RNA to protein.

Template Strand

The DNA strand that is used as a template for synthesizing mRNA.

mRNA (Messenger RNA)

The RNA copy of a gene that carries genetic information from the nucleus to the cytoplasm.

Introns

Noncoding regions of RNA that are removed during RNA processing.

Exons

Coding regions of RNA that are expressed and retained after splicing.

Poly-A Tail

A stretch of adenine nucleotides added to the 3' end of pre-mRNA, protecting it from degradation and exporting it from the nucleus

Untranslated regions (UTRs) *Exons*

The regions of RNA that are not translated

Spliceosome

A large complex of proteins/RNA that splices mRNA by interacting with the ends of an RNA intron, releasing the intron, and joining the two adjacent exons

Alternative RNA splicing

Creates different mRNA molecules from the same primary transcript (multiple proteins can be produced from the same gene; can produce proteins with different functions by adding or removing specific domains)

Alternative splicing: Domains

Discrete structural and functional regions of a protein (different exons can code for different domains)

Alternative RNA Splicing

A process that produces different mRNA molecules from the same primary transcript by including or excluding certain exons.

Promoter

Where RNA polymerase attaches and begins transcription

5’ cap

A modified guanine nucleotide placed on the 5’ end of pre-mRNA