This document discusses RNA processing in eukaryotes. It explains that there are three main steps in RNA processing: RNA capping, polyadenylation, and splicing of introns. RNA capping involves adding a 5' cap to protect the RNA from degradation. Polyadenylation involves adding a poly-A tail to the 3' end. Splicing of introns involves removing introns and joining exons to produce a mature mRNA that can be translated into a protein. Small nuclear RNAs (snRNAs) help form spliceosomes, molecular machines that catalyze splicing. Alternative splicing can result in different mRNAs and protein isoforms from the same gene.