Simplified DNA Model Project
Instructions for Creating the Molecules in the DNA Model
- Using one color of paper, cut out 7 circles (phosphate) about 2.5 cm across.
- Using a second color of paper, cut out 7 squares (ribose) about 2.5 cm across.
- Cut out the bases to match the first three bases and the extras. We call these the complementary bases.
You will eventually glue your model on the back of this paper. Hint: arrange the model first on your table - then glue it when you are sure it is correct.
Assembling the strands (phosphate-ribose backbones).
- Make a column of 3 phosphates (circles) and 3 riboses (squares) to form the backbone of one DNA strand. Place the phosphates and riboses about 2.5 cm apart. Follow the phosphate - ribose - phosphate - ribose - phosphate - ribose pattern.
- Draw lines between the phosphates and riboses to represent the bonds between the molecules.
- From the right side of each of the riboses, draw a 2.5 cm line at a 90° angle to the square. One line for each square.
- Make an identical duplicate phosphate-ribose strand. Set it aside.
Add the bases to the leading strand.
- For the first square of the first phosphate-ribose backbone you made, place the first base (from step III above) at the other end of this line. This line represents the bond between the ribose and the base.
- Add the other two bases to the other two riboses. Reading down the strand, the three bases should in the same order as the three bases in step III above.
- This phosphate-ribose backbone with it's bases we will call the leading strand. Label it such.
Add the bases to the lagging strand.
- This second phosphate-ribose backbone with it's bases we call the lagging strand. Label it such when you are done.
- You must place the complementary bases on the lagging strand so these bases line up and match the bases of the leading strand. Remember - confusion means you are thinking.
- When you are happy with your model, glue it to the back of this paper.
- Make a key to your paper pieces using the extra paper pieces. Label each paper shape with the name of the molecule it represents. Be sure to label the strands.