In higher Eukaryotes, upon transcription of a gene, a complex set of reactions take place to remove fragments of a sequence (introns) from transcribed RNA. A large macro-molecular machine (the spliceosome) recognizes the ends of introns, brings ends into close proximity and catalyzes the splicing reaction. The selection of the location of the ends of introns (splice sites) determines the final message produced at the end of the process. In some cases, an alternative set of splice sites are chosen, and as a consequence different message is produced. This phenomenon is known as alternative splicing. It is now realized that nearly every Human gene undergoes alternative splicing, producing large variability in types and number of transcripts produced. In this thesis, we examine the functional and structural consequences of alternative splicing on proteins, we look into the mechanism of formation of complex splicing patterns, and examine the role of noise in the process.