Transcription in Prokaryotes PPT: Mechanism And Process
What is Transcription in Prokaryotes:
Prokaryotic transcription, also described as bacterial transcription, is the process of copying a fragment of bacterial DNA into a freshly produced strand of mRNA, which is then translated into proteins by the enzyme RNA polymerase and other transcription factors. Bacterial transcription takes place in the cell’s cytoplasm
Mechanism of Transcription in Prokaryotes:
In prokaryotes, transcription needs a partial unwinding of the DNA double helix in the RNA production region which is referred to as a transcription bubble. For each gene, transcription begins with the identical DNA strand, known as the template strand. This procedure is completed into three stages:
- Initiation: Near the initiation site, the double helix DNA strand is unwounded and becomes single-stranded. The RNA polymerase enzyme attaches to the promoter sequence (TATA box) and initiates single-stranded DNA transcription. Sigma factors are responsible for the RNA polymerase enzyme’s binding to the Sigma factors are responsible for the RNA polymerase enzyme’s binding to the Sigma factors are responsible for the RNA polymerase enzyme’s binding to the promoter.
- Elongation: The sigma factor is removed from the promoter after the synthesis of more than 10 base pairs of long RNA. The RNA polymerase enzyme then moves in a continuous 5′ – 3′ path while generating RNA.
- Termination – This is the final stage of the transcribing process. There are two types of mechanisms in it.
-Transcription termination that is not dependent on Rho: transcription is stopped by a specific sequence in terminator DNA. Invert repeats in the terminator DNA cause complementary pairing as the hairpin structure’s transcript RNA. The RNA polymerase separates from the DNA template as a result of this.
-Rho-dependent transcription termination: Rho protein stops transcription. After the translation is finished, it binds to RNA, but transcription continues. This factor induces the RNA polymerase to separate from the DNA.