Lecture 49 - Dr Joanna Long MBI LG-126 [email protected]

Info icon This preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Dr. Joanna Long MBI LG-126 [email protected] Office hours: 2-4 pm on Thursdays or by appointment Lectures 49-54 (Lectures 47-48 after 54) Today’s lecture: Transcription (pp. 980-1020) Preprinted lecture notes 66-69, 98-104 Download (suggested) from http://biochem.med.ufl.edu/coursetemp.php?cid=44 or http://www.mbi.ufl.edu/facilities/msg/bch4024-notes.html Flow of genetic information --- the “Central Dogma” DNA RNA Protein Replication Transcription Translation messenger RNA (mRNA) transfer RNA (tRNA) ribosomal RNA (rRNA)
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
2 RNA transcription is actively regulated ¾ Not all DNA is transcribed in a given cell (less than 50% even in prokaryotes) ¾ For example, E. coli only produces the enzymes needed for lactose utilization when lactose is in the growth media ¾ François Jacob and Jacques Monod noted mutants of E. coli which had errors in regulating the production of β - galactosidase and proposed a macromolecular repressor regulated the level of enzyme production ¾ They hypothesized the repressor binds to a specific operator sequence in DNA (1961) ¾ This is now known as the operon model Transient messenger RNA (only observed with more sensitive radiolabeling) Stable ribosomal RNA (seen by UV at A 260 ) has three characteristic molecular weights K. Asano, J. Mol. Biol . 14:71-84 (1965) Differentiating RNA
Image of page 2
3 Messenger RNA --- information link between DNA / ribosomes ¾ Heterogeneous in size like the proteins transcribed from mRNA ¾ Rate of synthesis: ~ 50 nucleotides/sec/molecule (DNA replication is up to 1000 nucleotides /sec/molecule) ¾ Fidelity: error rate of about 10 -5 (DNA is 10 -9 - 10 -10 ) ¾ Degradation (t 1/2 ) is fast compared to other RNAs and DNA Prokaryotes: 3-4 minutes (allows rapid adaptation) Eukaryotes: hours-days ¾ Only one strand of DNA is transcribed for a particular gene— ”sense strand” ¾
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern