Question

Describe the process of Transcription ofRNA. What is the difference between replication and duplication?

Answer 1

Transcription is the copying of genetic information from a DNA into RNA. Transcription occurs in three stages: initiation, chain elongation, and termination.
1. Initiation:
RNA polymerase binds to DNA at a specific sequence of nucleotides called the promoter.
The promoter contains an initiation site where transcription of the gene begins.
RNA polymerase than unwinds DNA at the beginning of the gene.

2.Elongation:
Only one of the unmounted DNA strands acts as a template for the RNA synthesis.
RNA polymerase can only add nucleotides to the 3' end of the strand so like DNA, RNA must be synthesized in the 5' to 3' direction.
Free ribonucleotide triphosphates from the cytoplasm are paired up with their complementary base on the exposed DNA template.
RNA polymerase joins the ribonucleoside triphosphates to form an mRNA strand.
As RNA polymerase advances, the process continues.
The DNA that has been transcribed, re-winds to form a double helix.
3.Termination:
RNA polymerase continues to elongate until it reaches the terminator, a specific sequence of nucleotides that signals the end of transcription.
Transcription stops and mRNA polymerase and the new mRNA transcript are released from DNA.
The DNA double helix reforms.
The termination sequence usually consists of a series of adjacent adenines preceded by a nucleotide palindrome.
This gives an RNA molecule that assumes a stem-and loop configuration.
This configuration stops RNA polymerase from transcribing any further.

Replication is the process of duplicating or producing an exact copy of a polynucleotide strand such as DNA.
Duplication is the act or process of duplicating or repeating a region in the genetic material or chromosome.