RNA splicing is a process that occurs during the maturation of pre-mRNA molecules into mature mRNA molecules. This process involves the removal of introns non-coding regions and the joining of exons coding regions to produce a continuous coding sequence. The chemical modifications that occur during RNA splicing include the following:1. 5' splice site cleavage: At the 5' end of the intron, a specific sequence called the 5' splice site is recognized by the spliceosome, a large ribonucleoprotein complex. The spliceosome cleaves the phosphodiester bond between the 5' splice site and the upstream exon, releasing the 5' end of the intron.2. Lariat formation: The 2' hydroxyl group of a conserved adenosine residue within the intron attacks the 5' splice site, forming a 2',5'-phosphodiester bond and creating a lariat-shaped intron structure.3. 3' splice site cleavage: The spliceosome recognizes the 3' splice site at the end of the intron and cleaves the phosphodiester bond between the 3' splice site and the downstream exon, releasing the 3' end of the intron.4. Exon ligation: The free 3' hydroxyl group of the upstream exon attacks the 5' phosphate group of the downstream exon, forming a new phosphodiester bond and joining the two exons together.These chemical modifications have several impacts on the function and stability of the resulting mRNA molecule:1. Increased coding potential: By removing non-coding introns and joining coding exons, RNA splicing generates a continuous coding sequence that can be translated into a functional protein.2. Alternative splicing: The process of RNA splicing can generate multiple mRNA isoforms from a single pre-mRNA molecule by selectively including or excluding specific exons. This increases the diversity of proteins that can be produced from a single gene, allowing for the generation of protein isoforms with distinct functions or tissue-specific expression patterns.3. mRNA stability: Proper splicing is crucial for mRNA stability, as unspliced or improperly spliced mRNA molecules are often targeted for degradation by cellular quality control mechanisms. This ensures that only correctly processed mRNA molecules are translated into functional proteins.4. Nuclear export: The splicing process is coupled with other mRNA processing events, such as the addition of a 5' cap and a 3' poly A tail. These modifications are important for mRNA stability and efficient nuclear export, allowing the mature mRNA molecule to be transported from the nucleus to the cytoplasm for translation.