Britannica Sources used in this answer

How do hydrogen bonds help hold DNA molecules together?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Bohr model diagram of a hydrogen atom showing a green nucleus labeled H, a single electron orbit, and text with atomic mass 1.008 and electron configuration 1. — atom The Bohr model describes the structure of atoms, in this case hydrogen.

Hydrogen bonds are essential for maintaining the structural integrity of DNA molecules. They function by forming specific interactions between complementary nitrogenous bases located on the two strands of the DNA double helix.12

Specifically, these bonds facilitate the precise pairing of adenine with thymine and guanine with cytosine. This "keying together" of base pairs creates the stable double-helix structure necessary for the accurate transmission of genetic information.12

Because these interactions are weaker than covalent bonds, they can be disrupted by heat in a process known as denaturation or melting, which allows the two strands to separate. This reversibility is vital for biological processes, as the strands can reassociate through renaturation when conditions cool, a property that scientists utilize in various molecular biology techniques.13