Bacteria are simple genetic units with all of the following properties, EXCEPT:

Prokaryotes can't have introns, because they have transcription coupled to translation.  They don't have time/space for that, since intron splicing will stop the coupling. Eukaryotes evolved the nucleus, where splicing can be done. The parts of the gene sequence that are expressed in the protein are called exons, because they are expressed, while the parts of the gene sequence that are not expressed in the protein are called introns, because they come in between the exons.