RNA processing Flashcards
1
Q
Role of mRNA
A
- combines with ribosomes to direct protein synthesis, and carries genetic information from DNA to ribosomes
2
Q
Primary transcription in prokaryotes
A
- Primary transcript is mRNA
- Translation starts before transcription starts
- molecules of RNA code for different proteins, polycistronic RNA
3
Q
Primary transcription in eukaryotes
A
- transcription takes place in the nucleus
- translation takes place in the cytoplasm
-RNA processing occurs
4
Q
RNA processing
A
- a process where the primary transcript gets converted into mRNA and then gets translated by the ribosome.
5
Q
Three chemical modifications during RNA processing
A
- The 5’ end of the primary transcript is modified by adding a special nucleotide called a 5’ cap.
- Polyadenylation, the addition of a string of nucleotides, the creation of a ponytail. ( on the end of mRNA stabilizes the molecule and helps export mRNA to the cytoplasm)
- The removal of the non-coding regions of mRNA. Through RNA splicing
6
Q
What is a 5’ cap? what does it do?
A
- The 5’ helps add stabilizes mRNA
- located at the end of the mRNA
7
Q
Steps of RNA splicing:
A
- the spliceosomes move introns closer to the 5’splice site.
- The proximity of the intron causes the RNA to split and form a loop and a tail (latriat)
- The lariat breaks down into induvial nucleotides
8
Q
Exons vs Introns
A
Exons: Protein coding regions
Introns: Non protein coding
9
Q
Ribosomal rRNA
A
Makes the most ribosomes crucial for translation. They are concentrated in the nucleus
10
Q
Transfer tRNA
A
carries individual amino acids used for translation
11
Q
MicroRNA (miRNA) and small interfering RNA (siRNA)
A
small regulatory molecules that can inhibit or destruct a transcript
12
Q
Alternative splicing
A
allows for different polypeptides to be made from a single gene.
