The sides of the DNA ladder are composed of alternating sugar and phosphate molecules. These molecules form the backbone of the DNA structure. The sugar used in DNA is deoxyribose, which is why DNA stands for deoxyribonucleic acid. The phosphate groups link the sugar molecules together, creating a strong and stable structure.
Attached to each sugar molecule is a nitrogenous base. These bases are the rungs of the DNA ladder and include adenine (A), thymine (T), cytosine (C), and guanine (G). The sequence of these bases along the DNA strand encodes genetic information.
In summary, the sides of the DNA ladder are made up of sugar and phosphate molecules, while the rungs are formed by pairs of nitrogenous bases.