Protein Synthesis - RNA Processing Flashcards
What is the second stage of Protein Synthesis called?
RNA Processing
In what organisms does RNA processing happen?
Eukaryotic celled organisms
Prokaryotes cannot perform RNA processing
Why does mRNA need to be protected before leaving nucleus?
It will otherwise be degraded by enzymes in the cytoplasm
What is the mRNA strand called before it undergoes RNA Processing
pre-mRNA
What is done to the 5’ end of mRNA to protect it?
A 5’ Methyl Guanosine Cap is added in fornt of the start codon
It is a modified guanosine triphosphate molecule
What are benefits of a 5’ methyl guanosine cap?
- Helps mRNA bind to ribosome
- Protects form enzyme attack
What is done to the 3’ end of mRNA to protect it
A 3’ Poly Adenine Tail is added after the stop codon
Repeated Adenine nucleotides added (creates stability)
What else is done to shorten and protect the mRNA strand?
Introns in the mRNA are removed, and remianing exons join back together
Exons are expressed so they stay
What is purpose having introns that don’t code in genes?
To help reduce risk of mutations having an impact on final production of protein
Introns are removed by what enzyme?
Splicosome
What type of mRNA is produced after Introns are removed?
Mature mRNA
What other process can sometimes occur while Introns are being removed?
Alternative Splicing
What occurs in Alternative splicing?
Some exons can be removed and/or some exons can be shuffled around in a new order
What is the purpose of Alternative Splicing?
To allow the same gene to create different mRNA sequences and therefore produce different proteins.
Which exons are unlikely to be removed/shufled in alternative splicing?
The first or last exons as they carry the start and stop codon
