Transcription Flashcards
Transcription in euk
DNA ->
DNA-> hnRNA
-takes place in the nucleus
Transcription in prok
Dna->
DNA -> mRNA
-takes place in the cytoplasm
What is a gene
DNA sequence that codes for a protein
What do we want to transcribe in transcription?
A gene
How many strands do we copy into RNA?
- only one strand
- –the “template strand” or “anti-sense”
- in replication you copy both strands
What is the difference between the comlementary DNA strand and the new RNA strand?
-Uracil instead of thymine
Promoter
-attracts RNA pol to come and bind to the gene
Start site
Where tracription begins
-the beginning of the gene after the promoter
What pulls the strands apart
RNA pol
What do you do once you make the strand of RNA?
- depends if you are a prok or euk
- prok: coupled to translation because both take place in the cytoplasm
mRNA
tRNA
rRNa
- mRNA is the only one that codes for proteins
- tRNA and rRNA are involved in translation of the mRNA
- in prok all three are made by the same pol
- in euk there are three dif pol that make them separate
RNA POL I
RNA POL II
RNA POL III
I- makes rRNA
II- makes mRNA
III-makes trRNA
Promoters in prok vs euk
-prok: there is a “-35” element and a
“-10” element called the pribnow box rich in A and T
-euk: tata box at “-25” rich in A and T
Euk splicing
- Only in euk
- exons code for part of the protein
- introns need to be cut out and the exons are spliced together
- you attach a 5’ cap at one end of splicing and a polyAtail
- it is then shipped out of the nucleus and makes it to the ribosomemfor translation
Where does transcription begin?
- begins at the start site
- binding begins at the promoter region
Replication starts at the origin of replication
