Paper DNA (Double Helix)

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I made one of these for my Biology class. It doesn't take very long and it looks pretty cool in the end. The one I made for school is colored. I've also made another one without using tools. Any way, here's what you need:

1 sheet of 8.5" by 11" paper
A pencil
A ruler

This can actually be done with any size of paper. This works best when the width of the sheet is around 8- 9 inches.

This could be used as a fun, cheap way to teach about DNA. Students would learn about the structure of a DNA strand and about how  the four chemicals (Guanine, Adenine, Thymine, and Cytosine) combine in long complex structures to create the blueprints for what the cell makes.

NOTE: The DNA in the photos twists towards the left. As explained to me DNA actually spirals to the right. This is just a matter of which way you make your folds. Thanks to yardleydobon for pointing this out.

Step 1: Mark It Down the Middle

Mark the paper down the middle. On a standard sheet of paper that's 4 1/4".

Step 2: Marking Out the Sugar- Phosphate Backbone.

Make one line 3/8" from each edge and do the same on either side of the middle line. This creates the Sugar Phosphate Backbone of the DNA.

Step 3: Marking Out Each Nitrogenus Base

Now, use your ruler to make a line every inch down the line. make sure these are even or it won't turn out right.

Then make a line across each rectangle you just made. The lines on each side should point inward like a "V". As you can see, I accidentally did this wrong in the picture.

If you want to color it, this is the step to do it. Just split each rectangle in half and color each according to the Nitrogenus base.

Remember: Adenine -> Thymine and Guanine->Cytosine

To color the back bone, split each section on the sides and middle across the middle and alternate black and white.

Step 4: Fold It in Half

Pretty straightforward.

Step 5: Fold the Backbone

Using the lines on each side, fold one up and the other down.

Step 6: Starting the Nitrogenus Bases.

Using the lines as a guide fold each of the rectangles back. It should now curl up into a little tube on it's own.

Step 7: Flip It Over

You should have no trouble doing this.

Step 8: Fold the Diagonals

Fold back on each diagonal line. Only fold inside of the rectangle. It should now twist into a spiral.

Step 9: Collapse the DNA

Starting at the top gently collapse the entire thing. Try not to crush it! Then pinch it together and make sure all of the folds are creased.

Step 10: Let Go!

Let go of the compressed DNA strand. Congratulations! You just finished! 

Step 11: A Little About DNA

For people who don't know all that much about DNA:

    DNA stands for Deoxyribonucleic Acid. It resides inside the nucleolus, which is in the nucleus of Eukaryotic Cells. In Prokaryotic Cells DNA free floats due to the cell's lack of a membrane. It is the blueprints to the many things a cell creates. Each section of DNA is called a nucleotide. A nucleotide is made of one phosphate molecule, one deoxyribose sugar molecule and one nitrogenus base. There are four types of nitrogenus bases. Thymine, Adenine, Guanine and Cytosine. Thymine only bonds with Adenine. Cytosine only bonds with Guanine. The specific order of Nitrogenus bases determines what the strand creates. The deoxyribose sugar and the phosphate create the sugar-phosphate backbone. The reason DNA twists is because of how the 3 components in a nucleotide bonds. Nothing in nature is usually perfect, and the 3 components must warp to be able to create a bond.