9th Biology DNA Model Project

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9th Biology DNA Model Project Powered By Docstoc
					                                   Biology – DNA Structural Model

Students (working alone or with a partner) are to build a structural model of DNA using materials from
home (no purchased DNA kits are to be used). Students should use their imagination and find materials
they already have at home to put together their models, minimizing purchased materials as much as

The following requirements need to be fulfilled:

      The model needs to be at least one 360o turn which includes 10 complementary-paired
      The “backbone” or sides of the DNA molecule should be composed of alternating deoxyribose
       (5-carbon sugar) and phosphate group molecules covalently bonded together
      Each nucleotide needs to consist of deoxyribose, a phosphate, and a nitrogenous base
      All nitrogenous bases should be covalently bonded to the deoxyribose molecule
      Complementary base-pairing rules need to be followed: A-T; C-G
      Bases which are purines need to be composed of 2 rings
      Bases which are pyrimidines need to be composed of 1 ring
      Complementary base pairs should be bonded together in the center of the molecule with
       Hydrogen bonds: 3 hydrogen bonds between C-G; 2 hydrogen bonds between A-T
      The model should be capable of standing up; it should resemble a spiral staircase and the sides of
       the molecule should not make contact at any point with each other
      A chart needs to be made which includes a diagram of the model and an explanation of what
       materials were used to represent each part of the DNA molecule

The model is worth 90 points and is due on or before Monday, February 27, 2012

       Chart – 20 pts.
           Name(s) must clearly appear on the front of the chart
           A drawing of the model should be on the front of the chart
           A Key should be included that explains what parts were used and what parts of the
                DNA molecule each represents.

       Model – 70 pts
          Nucleotides contain: Deoxyribose (5 pts.)
                                Phosphate group (5 pts.)
                                Nitrogen base (5 pts.)
                                Sugar/phosphate alternate down sides of molecule (5 pts.)
                                Nitrogen base attached to sugar (5 pts.)
          Base-pairing rules: Adenine paired with thymine (5 pts.)
                                Cytosine paired with guanine (5 pts.)
                                Purines have 2 rings (5 pts.)
                                Pyramidines have 1 ring (5 pts.)
                                2 hydrogen bonds between A-T (5 pts.)
                                3 hydrogen bonds between C-G (5 pts.)
          Form of molecule: Resembles a spiral staircase and can stand up (5 pts.)
                                Each full twist contains 10 paired nucleotides (5 pts.)
                                Model is at least one full 360o twist in length (5 pts.)

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