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DNA- double helix question?

The question is:

"If the DNA double helix is this:Strand 1 – 5’ A – A – T – T – C – G – C – T – A – G – C – 3’ Strand 2 - 3’ T – T – A – A – G – G – C – T – T – C – G – 5’ (anti-parallel)Describe the concern here and what will be done to correct the problem."

I know the problem is that the G, C, and T on strand 1 are the same on strand 2 when really under the G should be C, under C should be G, and under T should be A. But why? and how would it be fixed? I know there is an enzyme that checks for mistakes but not sure how it actually gets fixed.

1 Answer

  • 1 month ago
    Favorite Answer

    So, basically there is a 3-base mismatch between the two strands. Cells have a mismatch repair system that should be described in your text or notes. This involves proteins that detect this kind of error. Then, one of the strands is cut (cells can generally tell which strand is the older one, and that one is assumed to be correct), and the mismatched bases are removed and then replaced and ligated back. 

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