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Introns and Splicing

Discussion in 'Pre-Medical - MD' started by vixen, Nov 10, 2001.

  1. vixen

    vixen I like members 10+ Year Member

    Oct 17, 2000
    upstate ny
    I have been studying for my biochem all day and there is something that I have been trying to understand...but I don't seem to get it!! Can someone try and explain Introns and Splicing to me? In my Stryer book, they use the example of beta-globin of the hemoglobin gene...does anyone know how to explain the splicing, introns, exons and how this stuff happens...continuous genes and discontinous genes? Thanks :(
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  3. Scooby Doo

    Scooby Doo IEatShavedPussyCats 10+ Year Member

    Jul 9, 2001
    I can give you a basics of it...but I don't know all the details you probably want. This will probably be too basic for ya...

    So we have DNA.

    DNA is transcribed to RNA that includes all introns and exons.
    This mess of RNA is then cut up by ??? and the introns go bye-bye. All that remains are the exons which is what the meat and potatoes of your DNA really is. This RNA (which only contains exons) is then transLATED into protein via tRNA's and all that fun stuff. Let's see an example:

    Here's a random sequence of DNA (using fake bases)


    So take all the "Q's" as intronic sequence. (The main thing the intron is important for is signaling where the splicing can occur but that is too much in detail for this explanation.)
    So when you transCRIBE the basic DNA into RNA, we get the same sequence (except for switching T's to U's).

    So our RNA sequence is the same.
    Now we splice out the introns and we get:


    This can then be transLATED into protein and make an enzyme to detoxify the alcohol we drink.

    HOWEVER, humans have the wonderful ability to mix and match. Sooo, we could also get out:


    So just from that one sequence we found that there are many types of proteins that can be made! This is why the human genome is not much longer than say that of fly or something. Everything is condensed.

    Since you said you are taking biochem I am sure you already knew all this and I probably just wasted my time :(
    You probably want exacts....and I just can't remember it b/c my brain doesn't function anymore.
  4. Amy

    Amy Animal Lover Physician 10+ Year Member

    Feb 1, 2001
    Draper, UT
    Exactly how much detail are you looking for? I have a degree in molecular genetics, so I can probably help you out, but I'm not sure what you're looking for. Scooby did a good job explaining the basics. Remember also that the RNA forms a lariat structure in order to splice the introns.... the 2 ends of the intron come together and get spliced out, and then the 2 exons ligate together. Good luck with biochem...
  5. vixen

    vixen I like members 10+ Year Member

    Oct 17, 2000
    upstate ny
    Oh you guys are [email protected] awesome...thanks so much scooby for the basics...this book is so descriptive, I can't understand it if I don't understand the basics...this is what I I can plug in the details from here...thanks guys! :) :)
  6. slptodoc

    slptodoc Senior Member 10+ Year Member

    Oct 6, 2000
    Hey there,
    There's a GREAT book that you might find very helpful, it's called "Clinical Biochemistry Made Ridiculously Simple" by Stephen Goldberg, M.D.
    (around $22.oo)

    You can get it through:
    MedMaster, Inc.
    p.o. box 640028
    Miami, Fla 33164

    There is a whole series of these books. I found out how valuable they were when I was taking my neuro classes in grad school!

    I think you can get these over the net as well.

    Hope this helps!

    Good luck!
    L :D

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