trombone model?


10+ Year Member
Jul 6, 2006
  1. Medical Student
    I'm not sure this is actually important to know for the MCAT because it might be a little too much detail for DNA replication, but, in all the books that I've read specifically made for the MCAT, none of them talk about the trombone model for dna replication. Most of them show one pol working upward on the leading strand and the other pol working downward in a ratcheting fashion on the lagging strand. But I was taught the trombone model in bio class in which the two pols are connected at the fork and the lagging strand is looped around to reverse the polarity and then the lagging strand itself is ratcheted through the replisome. Again, maybe this is too detailed for the MCAT itself but I haven't seen this model in any of the books that I've seen and it sort of bothers me.


    Bonne Vivant Med Student
    10+ Year Member
    5+ Year Member
    Feb 2, 2006
    1. Medical Student
      My school's normal year of bio has genetics and mol bio as the second semester...

      from the MCAT material that I've gone over... they don't seem to care so much about it... I think that if you know what a polymerase does (and at the basic level of synthesizing a new strand) that seems to be enough for the material that I've been going over.

      It doesn't seem like they would ask about the specific orientation of the lagging strand (especially since many of the details are still theories... although I also learned that model). Besides, that would waste a question that they could ask about hormones of the menstrual cycle-- they are so obsessed with that!
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