Video Link: https://www.youtube.com/watch?v=8xsHESlnQsQ

03-08-2011 14:15 Lecture by Kevin Ahern of Oregon State University discussing Biochemistry Basics in BB 451. See the full course at oregonstate.edu This course can be taken for credit (wherever you live) via OSU's ecampus. For details, see ecampus.oregonstate.edu Download Metabolic Melodies at http://www.davincipress.com Related courses include BB 350 - oregonstate.edu BB 450 - oregonstate.edu BB 100 - oregonstate.edu Transcription (continued) 1. A third modification to eukaryotic mRNAs that occurs is called editing. In editing, a base is chemically changed or added to an existing mRNA. Trypanosomes are unusual in inserting the base 'U' in multiple places in many mRNAs. Doing so is essential to getting the code right for making many of their proteins. 2. A more common editing modification that occurs in human cells is that involved with the Apo B-100 / Apo B-48 protein. Both proteins are coded by the same gene. (Note that I got the two proteins backwards in the lecture. What follows is correct) This lipoprotein is found in chylomicrons (Apo B-48) and liver cells (Apo B-100). Liver cells lack an RNA editing enzyme that intestinal cells have. The editing enzyme converts a C in a CAA sequence in the coding region of the gene to a U, making the stop codon UAA. 3. Splicing is the fourth modification that happens to eukaryotic mRNAs. Splicing also occurs to tRNAs and rRNAs in eukaryotes. Splicing involves removal of internal sequences from RNA followed by joining of ends. The removed sequences are ...

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Bite-Sized Biochemistry #47 - Transcription III / Translation I - Video