mRNA Processing - Introns Flashcards
Does bacteria require several steps of proceesing in its mRNA?
No, this only occurs in eukaryotes.
Where does the mRNA processing occur?
In the nulceus’ cytoplasm
5’ cap?
Helps to stabilize and prevent degradation
Poly(A) Tail
Role in stopping gene transcription
How does the cell determine where introns and exons are found to be spliced?
Boundaries specified by recogintion sequences
-The GU-AG rule
What is characteristic of the base sequence at the start and end of intron sequences.
Start with GU
End with AG
Lariat structure?
Structure formed in pre-mRNA when introns are removed.
Are lariats debranched?
Yes, after the 3’ boundary has been cleaved.
Ligation of exons occur.
What is the spliceosome?
Large complex of proteins and RNA that is used as the splicing machinery
What is a snurp?
RNA molecule in conjunction with proteins that perform the splicing in pre-mRNA.
Proteins in the snRNPs are
splicing factors.
Help to make lariat loop in introns.
Purpose of snRNA?
To bind temporarily to the introns.
What happens after U4 is released?
The lariat loop is spliced
Why do eukaryotes have gene introns?
We don’t know why
