To the teacher: So much of what we do is aimed at the "seasoned" teacher that I decided to do three simple laboratories for the beginning teacher: Building a DNA Molecule, Mitosis in Motion and Mutation Gossip. These labs require minimal equipment. They were written for ninth and tenth grade biology students.
Using the compass, poke holes in the center of each deoxyribose sugar segment on both cords. Be careful not to accidentally poke yourself!
Make a key for the four bases telling the name and color you've chosen for each. Also pick a color for your hydrogen bond:
Divide each toothpick into two unequal parts (l long and l short) with a thin ring of color around the toothpick to represent a hydrogen bond. Then color or paint some of your toothpicks making sure the purine (adenine) is correctly paired with the pyrimidine (thymine). The purine part of the molecule should be LONGER than the pyrimidine part of the molecule and the two should be joined by the hydrogen bond.
Similarly, color or paint the other toothpicks making sure the purine (guanine) is correctly paired with the pyrimidine (cytosine). Again, the purine part of the molecule should be LONGER than the pyrimidine part of the molecule and the two should be joined by the hydrogen bond.
After the cords and toothpicks have dried, use Elmer's glue to hold the toothpick bases in the deoxyribose part of the cord. Dry. Twist and compress the molecule in a small jar so that it simulates the double helix shape of a DNA molecule.
Untwisted DNA Molecule
When you get ready to put the show together (i.e. staple it), prepare the cards as though you were going to shuffle them by hitting the cards on the table to make the edges equal and then bend them slightly to stagger the edges for better flipping. Staple and show.
Arrange the class into one long line. Give the first person in the line a LONG sentence. It can be a tongue twister or any other sentence you think might manage to be "garbled" as it moves its way up the DNA of a chromosome of people. Ask the first person to remember the sentence. Each person must say the sentence to their contiguous gene (neighbor) ONLY ONCE. If the neighbor gene doesn't hear it the first time, they must repeat what they think they heard. After everyone has said the sentence to their neighbor, ask the last person to repeat the sentence out loud. Compare it to the sentence the first person was given by you. Invariably, if you have a large class, the sentence is changed somewhere in its transmission. This represents a "mutation" analogous to the mistakes made when DNA replicates.
There are many variations on this lab such as having two lines to more closely simulate replication where one chromatid has the correct answer and the other plays "Mutation Gossip." The best might be to have each gene in a chromatid tell its corresponding gene in the other chromatid a message and then have the last person in each chromatid relate his or her correct/incorrect message at the end of the replication.
You may consider "planting" students with special messages to simulate certain types of mutations. Feel free to use your imagination to modify and improve this lab.