The structure of DNA can be compared to a ladder. It has an alternating chemical phosphate and sugar backbone, making the 'sides' of the ladder. ... These bases make up the 'rungs' of the ladder, and are attached to the backbone where the deoxyribose (sugar) molecules are located.
All of the parts of the DNA combine to make rungs. Those rungs are attached together with other rings and the DNA is twisted in a dibble helix to get its shape.
