* It's shaped like a twisted ladder. The two strands of DNA wind around each other, forming a spiral shape like a twisted ladder.

* The two strands are held together by hydrogen bonds. These bonds form between the nitrogenous bases on the two strands.

* The strands are antiparallel. This means they run in opposite directions (one strand runs 5' to 3', the other runs 3' to 5'). This allows the nitrogenous bases to pair up in the middle of the helix, creating the ladder rungs.

This double helix structure is crucial to DNA's function:

* Stability: The two strands are tightly intertwined, making the molecule stable and less likely to break.

* Replication: The double helix can easily be separated into two strands, allowing each strand to serve as a template for a new strand, ensuring accurate replication.

* Information storage: The sequence of the nitrogenous bases within the helix encodes the genetic information of an organism.

The discovery of the double helix structure was a major breakthrough in biology, and it earned James Watson and Francis Crick the Nobel Prize in 1962.