Page "Complementary DNA" Paragraph 2

According to the central dogma of molecular biology, when synthesizing a protein, a gene's DNA is transcribed into mRNA which is then translated into protein.

One difference between eukaryotic and prokaryotic genes is that eukaryotic genes can contain introns ( intervening DNA sequences ) which are not coding sequences, in contrast with exons, which are DNA coding sequences.

During transcription, all intron RNA is cut from the RNA primary transcript and the remaining pieces of the RNA primary transcript are spliced back together to become mRNA.

The mRNA code is then translated into an amino acid chain ( sequence ) that comprises the newly made protein.

Prokaryotic genes have no introns, thus their RNA is not subject to cutting and splicing.