Genetics: Transcription and RNA Processing

Vocabulary flashcards covering the key terms, mechanisms, and structures involved in transcription and RNA processing.

Barbara McClintock

A researcher at Cornell University who studied transposable elements, also known as jumping genes.

Transposons

Genes that move around to different chromosomal locations; also known as transposable elements or jumping genes.

Gene

A sequence of DNA that codes for a particular trait.

Transcription

The process occurring in the nucleus where a DNA sequence is copied letter by letter into an intermediate messenger RNA molecule.

RNA (Ribonucleic Acid)

A nucleic acid molecule that is typically single-stranded, contains a ribose sugar, is relatively short, and uses uracil in place of thymine.

Uracil

The nitrogenous base in RNA that replaces thymine, pairing with adenine during transcription.

Exon

A coding region of DNA that codes for a functional product or gene.

Intron

Non-coding spacer sequences located between genes; short for interfering sequences.

Promoter

A region located directly before a gene that functions like a boot record, signaling to the cell whether the gene should be turned on or kept off.

Sigma Subunit

A molecule that slides along DNA to recognize promoter sequences of genes that need to be turned on, serving as a flag to recruit RNA polymerase.

RNA Polymerase

An enzyme that reads DNA and synthesizes an RNA transcript in the $5$ to $3$ direction.

Heteronuclear RNA (hnRNA)

Premature messenger RNA produced immediately following transcription in the nucleus before processing occurs.

Exonucleases

Enzymes located in the cytoplasm whose sole function is to degrade and chop up DNA and RNA molecules from their ends.

7-mG Cap

A protective chemical cap added to the $5'$ end of hnRNA during processing to prevent degradation by cytoplasmic exonucleases.

Poly-A Tail

A sequence of multiple adenine residues added to the cleaved $3'$ end of hnRNA during processing for protection and export preparation.