The process by which messenger RNA or mRNA is synthesized from a DNA template is called transcription. Transcription occurs in three steps -- initiation, elongation and termination. Messenger RNA carries genetic material from DNA in the nucleus to the cytoplasm where protein synthesis occurs in organelles called ribosomes.
For transcription to occur, part of the double-stranded helical DNA has to be unwound. An enzyme called RNA polymerase starts separating the strands in a process called initiation.
The mRNA strand is built in the elongation step of transcription. Nucleotides that complement one of the DNA strands are linked together to make a chain.
Once RNA polymerase reaches a DNA code called the termination sequence, it releases and transcription is complete. This step is called termination.
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