Question

What are the initiation events associated with Replication and Transcription (in the prokaryotic models):

Replication:

Transcription:

Answer 1

Initiation events of replication in prokaryotes :-

The replication of DNA begins at special sites called origins of replication (ori) , short streches of DNA having a specific sequences of nucleotides which contains multiple binding sites for the initiator protein.
Prokaryotes (bacteria) have circular DNA and in that there is generally one origin of replication is present.

The parental strands seperate at the origin ,forming a replication bubble with two forks.

Helicases unwinds the parental double helix , molecules of Single staranded binding (SSB) proteins stabilize the unwound template strands.

Initiation events of transcription in prokaryotes :-

Prokaryotes use the same RNA polymerase to transcribe all of their genes.

Transcription in prokaryotes requires the DNA double helix to partially unwind in the region of mRNA synthesis. The region of unwinding is called a transcription bubble.

RNA polymerase initiates transcription at specific DNA sequences called promoter.

In prokaryotes the RNA polymerase itself specifically recognizes and binds to the promoter.

After RNA Polymerase binds to the promoter , the DNA strands unwind and the polymerase initiates RNA synthesis at the start point on the template strand.