Types I and II Self-Splicing (Autocatalytic) Introns in mRNA

The video tutorial explains RNA processing, focusing on mRNA splicing. It introduces the addition of the 5' cap for stability and ribosome recognition. The tutorial covers self-splicing RNAs, detailing Group 1 and Group 2 introns. Group 1 introns require a guanosine cofactor, while Group 2 introns form a lariat structure through internal nucleophilic attack. The video concludes with a comparison of these mechanisms, emphasizing the role of secondary structure in splicing.

What is the primary function of the 5' 7-methylguanosine cap in mRNA processing?

• To degrade mRNA

• To stabilize the 5' region and aid in ribosome recognition

• To splice introns

• To add a poly-A tail

What distinguishes self-splicing RNAs from other types of RNA splicing?

• They do not require proteins

• They involve DNA instead of RNA

• They occur only in prokaryotes

• They require a spliceosome

In Group 1 intron splicing, what role does the guanosine cofactor play?

• It degrades the intron

• It stabilizes the exon

• It initiates the transesterification process

• It acts as a leaving group

What is the final product of Group 1 intron splicing?

• A double-stranded RNA

• A lariat structure

• A linear intron

• A circular intron

How do Group 2 introns differ from Group 1 introns in their splicing mechanism?

• They do not splice at all

• They require a guanosine cofactor

• They form a linear intron

• They use an internal 2' hydroxyl group for splicing

What structure is formed as a result of Group 2 intron splicing?

• A linear chain

• A lariat structure

• A double helix

• A protein complex

What is the main reason for the formation of a lariat structure in Group 2 intron splicing?

• The degradation of the exon

• The presence of a spliceosome

• The use of a free guanosine cofactor

• The nucleophilic attack from within the intron