Transcription

DNA –transcription -> RNA

Types of RNA

a) m-RNA : contain and carry genetic information coded in DNA to the cytoplasm and finally attach to ribosome.

b) r-RNA : Role in protein synthesis

c) t-RNA : carry amino acids to the site of protein synthesis.

Process of transcription

a. Initiation:

• It involves binding of RNA polymerase to promoter region of DNA.

b. Elongation:

• Once the promoter region has been recognized by the holoenzyme, it results to local unwinding of DNA helix.
• After binding, RNA polymerase begins to synthesize DNA sequence and σ sub units is released.

c. Termination:

• The elongation of RNA chain continues until a termination signal is reached.
• The RNA polymerase stops synthesis and the nascent RNA is separated from the DNA template.