RNApolimeráz

RNApolimeráz is the enzyme responsible for synthesizing RNA from a DNA template in a process called transcription. This fundamental process is crucial for gene expression in all known organisms, from bacteria to eukaryotes. RNApolimeráz reads the DNA sequence and builds a complementary RNA strand, carrying the genetic information from DNA to be used in protein synthesis or other cellular functions.

There are different types of RNApolimeráz in eukaryotes, each specializing in transcribing specific classes of RNA. For example, RNApolimeráz I transcribes ribosomal RNA (rRNA), RNApolimeráz II transcribes messenger RNA (mRNA) and some small nuclear RNAs (snRNAs), and RNApolimeráz III transcribes transfer RNA (tRNA) and other small RNAs. In prokaryotes, a single RNApolimeráz typically transcribes all types of RNA.

The mechanism of transcription involves RNApolimeráz binding to a promoter region on the DNA, unwinding the DNA double helix, and then adding RNA nucleotides one by one to the growing RNA chain using the DNA as a template. This process continues until a terminator signal is encountered, at which point the RNApolimeráz detaches from the DNA and releases the newly synthesized RNA molecule. The fidelity of transcription is maintained by the enzyme's ability to select the correct nucleotides based on base pairing rules.