Transcription of a gene (Part 1)

An enzyme, RNA polymerase, uses one strand of DNA as a template to synthesize a pre-mRNA molecule.


Newly forming RNA transcript Gene region l—’% 5’ Promoter region ; RNA polymerase, the enzyme DNA template DNA template that catalyzes transcription winding up unwinding (a) RNA polymerase binds to a promoter in the DNA, (b) The polymerase begins to move along the DNA and unwind it. along with regulatory proteins (initiation). The binding As it does. it links RNA nucleotides into a strand of RNA in the order positions the polymerase near a gene in the DNA. specified by the base sequence of the DNA (elongation). Only one strand of DNA provides a template for The DNA double helix rewinds after the polymerase passes. The transcription of mRNA. structure of the "opened" DNA molecule at the transcription site is called a transcription bubble, after its appearance. GCengege Lsem'ng. All fights Reserved.