BIOL 1020 Lecture 31: Lecture 31

• School: University of Manitoba
• Department: Biological Sciences
• Course: BIOL 1020
• Professor: Joy Stacey

Document Summary

Enzymes in the eukaryotic nucleus modify pre-mrna before the genetic messages are dispatched to the cytoplasm. Some interior parts of the molecule are cut out, and the other parts spliced together. Most eukaryotic genes and their rna transcripts have long noncoding stretches of nucleotides that lie between coding regions. These noncoding regions are intervening sequences or introns. The other regions are called exon because they are eventually expressed, usually translated into amino acid sequences. Rna splicing removes introns and joins exons, creating an mrna molecule with a continuous coding sequence. Functioning mrna leaves the nucleus into the cytoplasm to be translated into polypeptide. Some genes can encode more than one kind of polypeptide, depending on which segments are treated as exon during rna splicing. Enzyme for digesting mother"s milk- depending on lifespan wouldn"t need exon 1". A cell translates mrna message into protein with the help of transfer rna (trna) made by transcription of dna.