logo
AAT Bioquest

How many types of RNA are formed during transcription?

Posted February 14, 2023


Answer

The three types of RNA that are formed during transcription are messenger RNA, ribosomal RNA, and transfer RNA. mRNA is transcribed from DNA and has the necessary genetic material to produce proteins. Prokaryotic mRNA can synthesize proteins immediately without additional steps. In contrast, in eukaryotes, a newly transcribed RNA strand is known as a pre-mRNA and must mature to form an mRNA. Pre-mRNA strands have noncoding and coding regions, where introns are spliced and exons are attached together during pre-mRNA processing. The 5’ cap joins the 5’ end of the RNA transcript while the 3’ end is polyadenylated. The 5’ cap is responsible for protecting the mRNA from degradation and the 3’ poly (A) tail assists with the ability and transport of mRNA.

tRNAs are molecules that translate mRNA into proteins. They are made of a cloverleaf structure that has a 3’ acceptor site, 5’ terminal phosphate, T arm, D arm, and an anticodon arm. The function of tRNA is to transport amino acids on the 3’ acceptor site to a ribosome complex with the assistance of aminoacyl-tRNA synthetase. When an amino acid binds to the tRNA, it is known as an aminoacyl-tRNA. Each type of amino acid on a tRNA molecule is specific to the mRNA codon. The anticodon arm of the tRNA molecule is the area of the anticodon. 

rRNAs are responsible for creating ribosomes that are vital in protein synthesis. All ribosomes have one small and one large subunit. In eukaryotic cells, the small 40S and large 60S subunits form an 80S ribosome. In prokaryotic cells, the large 50S and small 30S subunits form a 70S ribosome. Ribosomes contain an exit (E),acceptor (A), and peptidyl (P) sites to bind aminoacyl-tRNAs and connect amino acids together to generate polypeptides. 

Additional resources

From DNA to RNA

DNA and RNA Quantitation

Portelite™ Fluorimetric RNA Quantitation Kit*Optimized for Cytocite™ and Qubit™ Fluorometers*