Transcription

Transcription is the synthesis of RNA from a DNA template by RNA polymerase. It copies selected genetic information into RNA without changing the DNA sequence.

RNA polymerase: An enzyme that synthesizes RNA by joining ribonucleotides according to a nucleic-acid template. It reads the DNA template and catalyzes each RNA-chain extension.
DNA: A molecule that stores hereditary information in a sequence of nucleotides. Its nucleotide sequence supplies the information copied during transcription.
DNA replication: The process by which a DNA molecule is copied to produce DNA molecules. Unlike transcription, it copies DNA into DNA and usually duplicates entire genomes.
Messenger RNA: An RNA molecule that carries coding information used by ribosomes to synthesize a protein. Transcription of protein-coding genes produces the precursor to this RNA.
Promoter: A DNA sequence that helps initiate transcription by recruiting RNA polymerase and associated factors. Promoter recognition determines where transcription begins.
RNA: A nucleic acid usually composed of single-stranded chains of ribonucleotides. It is the product whose sequence is built from the DNA template.
Translation: The synthesis of a polypeptide using the codon sequence of an RNA molecule. It uses an RNA product to build protein rather than copying DNA into RNA.
Ribosomal RNA: RNA molecules that form structural and catalytic components of ribosomes. Transcription supplies the abundant RNA that builds ribosomes.
Transcription initiation: The stage in which RNA polymerase and required factors assemble at a gene and begin RNA synthesis. This is the first stage after polymerase is positioned at a promoter.
Nucleotide: A molecular unit consisting of a sugar, a phosphate group, and a nitrogenous base. RNA polymerase joins ribonucleotides to construct the transcript.

Linked from 31 pages