What role do hydrogen bonds play in the DNA structure?

Hydrogen bonds are crucial in maintaining the structure of DNA by holding the two strands together through base pairing. In the double helix formation, specific nitrogenous bases pair with each other: adenine pairs with thymine, and guanine pairs with cytosine. These pairings are stabilized by hydrogen bonds – two between adenine and thymine, and three between guanine and cytosine. This arrangement allows the DNA to maintain a consistent width and contributes to the overall stability of the double helix structure.

The other roles mentioned, such as forming the backbone of DNA or linking nucleotides together, are primarily due to covalent bonds. The DNA backbone is made up of alternating sugar and phosphate groups, bound together by strong covalent bonds. The energy required for DNA replication comes from nucleoside triphosphates, not hydrogen bonds. Consequently, hydrogen bonds are specifically important for the integrity and fidelity of base pairing between the two strands.