Final answer:
Splicing involves the removal of introns from pre-mRNA transcripts. There are different types of splicing, including spliceosomes and group II introns. Spliceosomes are protein complexes composed of proteins and small nuclear RNAs (snRNAs), while group II introns are self-splicing RNA molecules.
Step-by-step explanation:
Splicing is the process of removing introns from pre-mRNA transcripts. There are different types of splicing, including splicing mediated by spliceosomes and group II introns. Spliceosomes are protein complexes composed of proteins and small nuclear RNAs (snRNAs), while group II introns are self-splicing RNA molecules.
Both types of splicing involve the recognition of sequences at the 5' and 3' ends of the intron. Spliceosomes bind to these sequences, bringing them together to form a spliceosome complex. This complex catalyzes the removal of the intron and the ligation of the flanking exons to produce the mature mRNA.
In comparison, group II introns are self-splicing and do not require spliceosomes. They form a lariat structure, where the intron sequence is brought close to the branch site, allowing the intron to be cleaved and ligated together.