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Anonymous asked in Science & MathematicsBiology · 1 month ago

Which one is the correct electrophoresis pattern?

A sample of DNA (1000 copies of the same strand) is cut with the restriction enzyme EcoR1 into four different sized fragments (A-D), as shown in the diagram. A solution of the four fragments is placed in a well in an agarose gel and separated by electrophoresis (see stained gel below).

Could you also possible tell me the answer for question 6? I believe that there would be more bands of DNA

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2 Answers

  • 1 month ago

    Lane 3 shows the correct order of the bands. The larger fragments migrate more slowly in the gel, and the smaller ones migrate more rapidly.

    6. There would not be more bands. The bands formed would just be darker or slightly broader.

    7. There would be 11 bands. Since 3 cuts gives 4 bands, 10 cuts would give 11 bands.

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  • Ashley
    Lv 6
    1 month ago

    The gel would not have more bands.

    The bands are created based on the *size* of each fragment—smaller fragments travel further than longer fragments. The enzyme is cutting our strand of DNA into four fragments, at the same bases, every time. 1,000 times, 5,000 times—doesn’t matter. We’re still left with the same sized fragments. Therefore, we will still have the same number of bands, since the bands aren’t formed based on the number of copies we have, they’re formed by the size of our fragments. Does that make sense? 

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