Genetics & Evolution Box

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Link to lessons that are part of the Genetics & Evolution Box.

5. Secret Codes - Background

Teacher Background
The genetic code is a set of rules that guide how the sequence of DNA nucleotides is read by a cells machinery and turned into a sequence of amino acids that make up a protein. Incredibly, nearly all living things use the same genetic code!

To understand how DNA provides the instructions for making proteins, one first needs to understand a little about what a protein is. A protein, like DNA, is a polymer (a long molecule that is a chain of smaller repeating subunits). The subunits in proteins are called amino acids. There are 20 different amino acids that can be linked together in an infinite array of sequences of different lengths. These chains of amino acids form the proteins that do all the work in our bodies – building cells, generating energy, transporting materials, and more. For this activity, it is important to note that each amino acids has been assigned a single letter abbreviation which allows students to create protein “words” and “messages” with different sequences of amino acids.

5. Secret Codes - Logistics

Time
45-55 minutes

Grouping
Individual

Materials

  • Copies of Secret Codes handout
  • Optional: internet access and a computer projection system to show students 2 web-based videos of transcription and translation from DNA Interactive.

Setting

5. Secret Codes

Example secret DNA code Kids love secret codes and secret messages. In this activity, kids first discover how codes work by reading and writing secret messages written in Morse code. Next, ...

4. DNA Models - Sources and Standards

Sources
This activity was adapted from a DNA model designed by Lori Lambertson of the Exploratorium Teacher Institute.

For additional background materials, see:

  • Wikipedia article on DNA.
  • Read a copy of Watson and Cricks original 1953 article.
  • For the best online DNA resource I’ve seen, go to DNA Interactive. You will find interviews with scientists, gorgeous computer animations, lesson plans and fabulous web activities.
  • The classic book, The Double Helix: a personal account of the discovery of the structure of DNA by James Watson.
  • An alternative view of the role played by Rosalind Franklin, Rosalind Franklin and DNA by Anne Sayre.

4. DNA Models - Assessment

Assessment

  1. Have students draw, label and color pictures of DNA.
  2. Have students build other 3D models of DNA using different materials (beads, candy connected with toothpicks, Styrofoam peanuts, etc.). See the DNA Jewelry Project for one idea or leave the project open ended and have students select their own materials and design.

4. DNA Models - Lesson Plan

Lesson Plan

  1. Tell students that today they will be assembling a DNA puzzle. Show students each of the pieces and tell them what the letters on each represent. If you want, tell students the beginning of the DNA discovery story, especially how Watson and Crick created puzzle pieces to represent the different parts and tried to fit the pieces together in a way that made sense with the data that was known at the time.
  2. Pass out the puzzle pieces and instruct students to build a DNA molecule.

4. DNA Models - Getting Ready

Getting Ready

  1. Make photocopies of puzzle pieces, each on a different colored paper.
  2. Have students cut out 1 or 2 sheets per person, possibly as homework the night before the activity.

4. DNA Models - Background

Teacher Background
Although DNA was isolated in the 1800s, it was not until the 1900s that scientists believed DNA might store genetic information. By 1929, the 3 major components – the sugar deoxyribose, a phosphate group, and a nucleic acid – had been identified. Furthermore, it was known that the phosphate groups linked the molecule together in a long polymer, however it was assumed that the chains were short and that the bases repeated in the same fixed order.

4. DNA Models - Logistics

Time
30 minutes to cut DNA model pieces (It is possible to assign each student a sheet of puzzle pieces to cut out as homework the night before.)
20 minutes to assemble puzzle
10 minutes to tape puzzle together
10-20 minutes to discuss DNA structure and the discovery of the DNA structure

Grouping
Individual students gradually linking their puzzles together to create a long strand.

4. DNA Models

DNA structure click on the image to see it rotateIn this activity, students “discover” the structure of DNA by playing with puzzle pieces representing the component pieces of the DNA ...