Relative to the secondary structure of DNA, the purine and pyrimidine bases lie inside the helix, in planes perpendicular to the helical axis; the deoxyribose and phosphate groups form the outside of the helix.

Question

Quizplus · Accepted Answer

In the DNA double helix, the purine (adenine and guanine) and pyrimidine (cytosine and thymine) bases are stacked inside the helix, with their planes perpendicular to the helical axis. This arrangement allows for the bases to pair through hydrogen bonding (A with T, and C with G), stabilizing the structure. The deoxyribose sugar and phosphate backbone form the exterior of the helix, providing structural support and protection for the genetic information encoded in the base sequences.

Relative to the Secondary Structure of DNA, the Purine and Pyrimidine