Hydrogen bonding in DNA

The DNA structure showing the specific bonding of the four bases

Scan the image above for more information

G = Guanine, C = Cytosine, T = Thymine, A =Adenine

Why are the bases not covalently bonded to the bases on the opposite(complementary) strand of DNA? Think of how the DNA molecule must replicate by unfolding.

Click to see an animation of Guanine and Cytosine hydrogen bonding to each other.
The phosphorus- sugar backbone of the DNA molecule covalently bonded. Hydrogen bonding between Guanine and cytosine. Click for a more detailed look Hydrogen bonding between Guanine and cytosine. Click for a more detailed look Hydrogen bonds.Click to see more information. Hydrogen bonds The phosphorus- sugar backbone of the DNA molecule