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    HBS 131 ResponseSheet

    Uploaded by

    Delilah Yacoub

    Copyright:

    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd

    HBS 131 ResponseSheet

    Uploaded by

    Delilah Yacoub
    113 views3 pages

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    HBS_131_ResponseSheet (2)

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    113 views3 pages

    HBS 131 ResponseSheet

    Uploaded by

    Delilah Yacoub

    Copyright:

    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
    of 3

    PLTW Biomedical Science Human Body Systems

    Activity 1.3.1 Student Response Sheet


    Part A – Restriction Enzymes
    Restriction enzymes are a tool that allows us to pinpoint human identity down to single differences in our DNA. Work
    through the following simulation so you can see these molecular scissors in action.

    Find out more about restriction enzymes by viewing the animation listed below.
     Dolan DNA Learning Center: Restriction Enzymes http://www.dnalc.org/ddnalc/resources/restriction.html

    1. Each enzyme recognizes a very specific sequence in the DNA. For example, the enzyme PstI recognizes the
    sequence:

    CTGCAG
    GACGTC

    The enzyme scans DNA for this sequence and makes a cut as indicated by the arrows.

    Visit the list of restriction enzymes found at the bottom of the page on
    http://en.wikipedia.org/wiki/Restriction_enzymes. Find the unique sequence (restriction site) that is recognized by
    EcoRI and by HindIII. Write the double-stranded sequence below and draw an arrow between the base pairs to
    indicate where the enzyme would make its cut.

    EcoRI: HindIII:

    2. What do you notice about each restriction site? What does the word palindrome mean?

    3. Using the information above, digest the DNA samples for Person 1 and Person 2 using EcoRI. Scan the strand for
    the restriction site and draw an arrow any place this enzyme would make a cut. Beneath each strand indicate the
    number of fragments that would be created and the size of each fragment. The size of a fragment is determined by
    counting the number of bases on the top strand of each fragment and is recorded in bases. Some of the pieces will
    have bases overhanging the edge (sticky ends). For example, for a piece that looks like

    the size of the fragment would be listed as 9 base pairs (9 bp).

    Person 1:

    GGAATTAAGCTTATTGAATTCTTATAGAATTCGGGGCCCAAGCTTATGAATTCAATT

    © 2021 Project Lead The Way, Inc. 1


    PLTW Biomedical Science Human Body Systems

    CCTTAATTCGAATAACTTAAGAATATCTTAAGCCCCGGGTTCGAATACTTAAGTTAA

    Number of restriction fragments (pieces of DNA after digestion): _________

    Size of restriction fragments (count the number of bases on the top strand of each fragment) - listed from largest
    to smallest.

    ___________________________________________________________________________________________

    Person 2:

    CCATATAGAATTCAAGCTTAAGAATTCGGGGGAACGTTGAATTCAATTAATTGGG
    GGTATATCTTAAGTTCGAATT CTTAAGCCCCC TTGCAACTTAAGTTAATTAACCC

    Number of restriction fragments (pieces of DNA after digestion): _________

    Size of restriction fragments (count the number of bases on the top strand of each fragment) - listed from largest
    to smallest.

    ___________________________________________________________________________________________

    © 2021 Project Lead The Way, Inc. 2


    PLTW Biomedical Science Human Body Systems

    Part B – Gel Electrophoresis of Restriction Enzymes


    After you have reviewed the principles of electrophoresis, use what you know to complete the following:

    1. “Run” your restriction fragments from both Person 1 and Person 2 on the gel drawn below. Use the DNA marker
    lane to help you draw in the bands you would see in each lane of the gel.

    2. Place a large “+” on the end of the gel diagram where the positive electrode would go. Place a large “─” on the end
    of the gel diagram where the negative electrode would go. Using what you know about the structure of DNA,
    explain why this placement is crucial to separating the fragments.

    3. Use an asterisk (*) to indicate the smallest fragment shown on the gel.

    4. Compare the DNA fingerprint of Person 1 and Person 2. Explain how this fingerprint would have looked different
    if you had digested the DNA of each person with HindIII instead of EcoRI.

    Think about these principles as you analyze your actual gel results from the missing person experiment. Remember
    that in the actual lab you digested each sample with two different restriction enzymes in separate reactions.

    © 2021 Project Lead The Way, Inc. 3

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