Summer Research Program for Science Teachers

Rosa Jimenez

Washington Irving H.S.

2000

 

Teaching the Chemical and Structural Properties of DNA

OBJECTIVE: To teach students the chemical and structural properties of DNA, and how DNA is the basis for heredity. [9-12 Content Standard C- The molecular basis of heredity]

 

MOTIVATION: Have students work in pairs to answer the following questions:

        What do you know now about DNA?

        If you know anything about DNA, where did you learn about it?

        Where is DNA found in the cell and what is its role? [9-12 Content Standard C- The cell]

        What physical similarities, if any, do you see between you and your parents, your grandparents, your brothers and sisters or any other close relative? Why do you think this usually happens?

 

DEVELOPMENT: As the students answer these questions out loud to the class, I will write the factual comments that they know on the board and incorporate into their previous knowledge the following concepts that describe DNA:

        History (Watson and Crick)

        The three subunits that make up a nucleotide (a sugar , a phosphate and a base)

        Hydrogen bonding

        Base pairing (A-T, G-C)

        DNA twisted ladder

        DNA semi-conservative replication to show heredity.

 

SUMMARY: Have the students develop a small concept map showing the relationship between the different components of DNA. Further, try to label the parts of DNA in the attached figures (1, 2, 3, and 4).

 

HOMEWORK: Ask the students to create their own DNA model, which would clearly show the structure of DNA. Materials needed: crayons, regular typing paper, glue and scissors.

 

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