Gene Expression: Transcription

These flashcards cover key vocabulary terms related to gene expression and transcription to aid in exam preparation.

Transcription

The process of copying a segment of DNA into RNA, specifically messenger RNA (mRNA), through initiation, elongation, and termination.

Promoter

A DNA sequence where RNA polymerase binds to initiate transcription.

Coding Strand

The strand of DNA that has the same sequence as the mRNA (except for T replaced by U).

Template Strand

The strand of DNA that is used as a guide to synthesize the RNA transcript.

Sigma Factor

A protein involved in the initiation of transcription in prokaryotes that binds to the promoter and recruits RNA polymerase.

Elongation

The stage of transcription where RNA polymerase synthesizes the RNA transcript by adding nucleotides.

Termination

The end of transcription when RNA polymerase detaches from the DNA and the RNA transcript is released.

Spliceosome

A complex of RNA and proteins that removes introns from a pre-mRNA transcript.

Introns

Non-coding sections of a gene that are removed during RNA processing.

Exons

Coding sections of a gene that remain in the final mRNA after processing.

Alternative Splicing

A process by which different combinations of exons are joined to produce multiple mature mRNA variants from a single gene.

Rho-dependent Termination

A mechanism of transcription termination in prokaryotes that requires the rho protein to release the mRNA.

Rho-independent Termination

A mechanism of transcription termination in prokaryotes that occurs through the formation of a hairpin structure in the RNA.

5’ cap

A modified guanine nucleotide added to the 5’ end of eukaryotic mRNA that is important for mRNA stability and recognition by the ribosome.

Poly(A) tail

A stretch of adenine nucleotides added to the 3’ end of eukaryotic mRNA that increases the stability of the RNA transcript.

Polycistronic mRNA

A type of mRNA in prokaryotes that can code for multiple proteins due to multiple coding sequences.

Housekeeping Genes

Genes that are constantly expressed to maintain basic cellular functions.

Eukaryotic RNA Polymerases

Three types of RNA polymerases in eukaryotes, each responsible for synthesizing different types of RNA.

mRNA

Messenger RNA; the RNA that conveys genetic information from DNA to the ribosome for protein synthesis.

snRNA

Small nuclear RNA, involved in the splicing of pre-mRNA.

miRNA

MicroRNA, a small RNA molecule that functions in RNA silencing and regulating gene expression.