Question

the rungs of the ladder in the double helix are made up of

Answer 1

DNA is basically a long polymer of nucleotides.

Answer 2

It's backbone is made of sugars and phosphate groups joined by ester bonds.
Attached to each sugar is one of four types of molecules called bases, or the rungs.

Answer 3

The 4 bases for DNA are Adenine, Thymine, Guanine, & Cytosine.

Answer 4

Adenine and Thymine is a base pair and form two H-bonds.

Answer 5

Guanine and Cytosine is the other base pair, but forming three H-bonds.

Answer 6

These H-bonds stabilize the two helices.

Answer 7

So basically, each rung is made up of a Nitrogen base which is bonded with the corresponding Nitrogen base by hydrogen.