What components form outside the DNA helix?

The components that form outside the DNA helix are deoxyribose and phosphate groups. In the structure of DNA, the backbone consists of deoxyribose sugars linked by phosphate groups. This structural design plays a crucial role in the stability of the DNA molecule and in protecting the genetic information encoded within the base pairs that lie inside the helix.

Deoxyribose sugar forms part of the nucleotide structure, which is the building block of DNA. Each nucleotide is made up of a phosphate group, a deoxyribose sugar, and a nitrogenous base. The phosphate group connects to the 5' carbon of one deoxyribose and the 3' carbon of another, creating a strong phosphodiester bond that links the nucleotides together in a linear chain.

This arrangement forms the strong, stable outer structure of the DNA molecule, while the nitrogenous bases (adenine, thymine, cytosine, and guanine) align in the center, forming base pairs through hydrogen bonding. This key structural insight highlights the importance of deoxyribose and phosphate groups in maintaining the integrity and function of DNA.