Modeling Replication and Transcription of DNA
I- Purpose: Construct and analyze a model of DNA, Simulate a process of replication using a model, and Simulate process of transcription using a model.II- Materials:
- Plastic Soda Straws (54)
- 54 pushpins( 12 red, 12 blue, 12 yellow, 12 green, and 6 white)
- 54 paper clips
Part A: Making aModel of DNA
1. Cut the soda straws into 3cm pieces to make 54 segments.
2. Insert a pushpin midway along the length of each straw segment as shown in the figure in page 200. Push a paper clip into oneend of each straw segment until it touches the pin.
3. Keeping the pins in a straight line, insert the paper clip from a blue-pushpin segment into the open end of a red-pushpin segment. Addadditional straw segment to the red-segment end in the following order: green, yellow, blue, yellow, blue, yellow, green, red, red and green. Use the permanent markers to label the blue-segment end “top”.This chain of segment is one-half of your fist model.
4. Assign nucleotides to the corresponding pushpins colors as follows: red=adenine, blue=guanine, yellow=cytosine, and green=thymine.
5.construct the other half of your first model beginning with a yellow segment across from the blue pushpin at the top of your fist model. Keep the pins in a straight line. Link segments together according tothe base pairing rules.
6. When you have completed you model of one DNA segment, make a sketch of the model in your lab report. Use colored pencils or pens to designate the pushpins colors. Includea key that indicates which nucleotides each color represents in your sketch.
Part B: Modeling DNA Replication
7. Place the chains parallel to each other on the table with the top blue pin of thefirst chain facing the top yellow pin of the second chain.
8. Demonstrate replication by simulating a replication fork at the top pair of pins. Add the remaining straw segments to complete a new...
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