Transcription and Splicing

Cards (14)

What does the protein manufactured depend upon?
The DNA in the cell's nucleus.
What are proteins created on?
Ribosomes.
What are the two stages of protein synthesis?
Transcription and translation.
What is transcription? 
Where a gene on the DNA is copied into mRNA.
Where does transcription occur?
In the nucleus.
Why does transcription occur?
So DNA doesn't leave the nucleus and get damaged.
What is the first step of transcription?
The DNA helix unwinds to expose the nucleotide bases on the 2 strands.
What happens to one strand from the unwinded helix in transcription and why?
It acts as a template to make mRNA as it is single-stranded.
What is the unwinding of the DNA helix catalysed by?
DNA helicase.
What does the DNA helicase do in transcription?
It breaks the hydrogen bonds between bases.
What happens after DNA helicase breaks the hydrogen bonds in transcription?
Free mRNA nucleotides in the nucleus align opposite exposed complimentary bases.
What is the last step of transcription?
RNA polymerase bonds together the mRNA nucleotides to create a pre mRNA polymer chain.
What happens to the pre mRNA chain once it is copied?
It's modified and then leaves the nucleus.
How is pre-mRNA modified into mRNA?
Its introns are spliced out by a protein called spliceosome.