Question

What is transcription? Explain the process of transcription in bacteria by labelled diagram.

Answer 1

The process of transcription is the formation of the mRNA from the DNA with the help of the enzyme RNA polymerase.

Transcription in prokaryotes is carried out in three stages.

Initiation: In this step, RNA polymerase enzyme along with initiation factor (sigma) binds with DNA sequence at promotor and starts transcription.

Elongation: In this step RNA polymerase enzyme nucleoside triphosphate act as a substrate and polymerizes the nucleotides of templates as a complementary strand.

Termination: In this step terminator factor (rho) replaces the initiation factor at the termination point of DNA sequence.At this stage detachment of RNA and RNA polymerase enzyme with rho factor takes place.

In eukaryotes, transcription occurs in nucleus whereas in prokaryotes it occurs in the cytoplasm. In eukaryotes, RNA processing is required as its structural gene is monocistronic whereas in prokaryotes it does not require because its structural gene is polycistronic.