Transcription and translation in bacteria occurs in the cytoplasm of the cell. Whereas in eukaryotes, transcription occurs in the nucleus and translation occurs in the cytoplasm.
Complexities in Transcription in Eukaryotes
(i) The structural genes are monocistronic and split in eukaryotes.
(ii) The genes of eukaryotic organisms having coding or expressed sequences are called exons that form the part of mRNA and non-coding sequence are called introns, that do not form part of the mRNA and are removed during RNA splicing.
(iii) In eukaryotes, apart from the RNA polymerase found in the organelles, three types of RNA polymerases are found in the nucleus.
(iv) RNA polymerase I transcribes rRNAs (28S, 18S, and 5.8S).
(v) RNA polymerase II transcribes the precursor of mRNA (called as heterogeneous nuclear RNA (hnRNA).
(vi) RNA polymerase III helps in transcription of tRNA, 5S rRNA, and snRNAs (small nuclear RNAs).
(vii) The primary transcripts contain both the coding region exon and non-coding region intron in RNA and are non-functional called hnRNA.
(viii) The hnRNA undergoes two additional processes called capping and tailing.
(ix) In capping, an unusual nucleotide is added to the 5'-end of hnRNA methyl guanosine triphosphate.
(x) In tailing, adenylate residues (about 200–300) are added at 3'-end in a template independent manner.
(xi) Now the hnRNA undergoes a process where the introns are removed and exons are joined to form mRNA called splicing.
Translation in both eukaryotes and prokaryotes is similar
