Here's a breakdown:

* DNA Structure: DNA is a double helix, with two strands of nucleotides running in opposite directions. Each nucleotide consists of a sugar, a phosphate group, and one of four nitrogenous bases: adenine (A), guanine (G), cytosine (C), and thymine (T).

* Base Pairing: The bases on one strand of DNA form hydrogen bonds with the bases on the other strand. This pairing is specific:

* Adenine (A) always pairs with thymine (T), forming two hydrogen bonds.

* Guanine (G) always pairs with cytosine (C), forming three hydrogen bonds.

* Hydrogen Bonds: These weak bonds are crucial for holding the DNA strands together, giving the DNA molecule its characteristic double helix shape. They also allow for the DNA to easily separate during replication and transcription.

So, to summarize, hydrogen bonds are the glue that keeps the bases in DNA together, enabling the molecule to function correctly.