In a DNA double helix, what type of bonds form between the nitrogenous bases?

In a DNA double helix, hydrogen bonds form between the nitrogenous bases of the two strands. This bonding is crucial for the structure and function of DNA. Each base pairs specifically: adenine bonds with thymine via two hydrogen bonds, and cytosine bonds with guanine through three hydrogen bonds. These hydrogen bonds provide enough strength to hold the two strands of DNA together while still allowing the strands to separate during processes such as DNA replication and transcription.

The nature of hydrogen bonds, being relatively weak compared to covalent or ionic bonds, allows for the dynamic behavior required during cellular processes, where DNA needs to be unwound and then rewound frequently. Therefore, while other types of bonds, such as covalent bonds, are responsible for connecting the backbone of the DNA (the sugar and phosphate groups), it is the hydrogen bonds between the bases that hold the two strands of the double helix together and give DNA its specific base pairing properties. This balance of strength and flexibility is essential for the stability and functionality of genetic material.