BIOC 2580 Study Guide - Final Guide: Embryophyte, Archaea, Alternative Splicing

• School: University of Guelph
• Department: Biochemistry
• Course: BIOC 2580
• Professor: Shannon De Roo

Document Summary

One extra base can cause a whole frame shift. 90% of nucleotides that are transcribed are removed as introns within the nucleus. Exons are highly conserved, introns are not really. In nucleus, pre-mrna forms ribonucleoprotein particles that maintain the pre-mrna in an untangled and accessible conformation. There is a specific consensus sequence at both the 5" and 3" end of introns to signify where it will occur. 5" splice site consensus: ag (exon): guaagu (intron). The first gu in the intron are considered invariant. 3" splice site consensus: py py py py py py py-cag (intron): g--(exon) Long region of pyrimidines followed by cag (ag is considered invariant) A branch site that is also considered invariant is about 20-50 bases before the 3" splice site. Complex of proteins which all must bind to the consensus sequences at 5" and 3" sides of an intron to form a spliceosome.