transcription

• step one: the DNA helix unwinds to expose the bases to act as a template
• transcription -> where one gene on the DNA is copied into mRNA
• step two: only one chain of the DNA acts as a template
• step three: like with the DNA replication, this unwinding and unzipping is catalysed by DNA helicase
• step four: DNA helicase breaks the hydrogen bonds between bases
• step five: free mRNA nucleotides in the nucleus align opposite to the exposed complementary DNA bases
• step six: the enzyme RNA polymerase bonds the RNA nucleotides together to create a new RNA polymer chain - one entire gene is copied
• step 7: once copied the mRNA is modified and leaves the nucleus through nuclear pores
• following transcription, pre-mRNA has to be modified to become mRNA that is ready to leave the nucleus and take part in translation.
• in the process of pre-mRNA becoming mRNA the introns are spliced out by a protein called a spliceosome, leaving behind just exons